diff --git a/CONTEXT.md b/CONTEXT.md
index dfd6ef1..45a41c6 100644
--- a/CONTEXT.md
+++ b/CONTEXT.md
@@ -123,10 +123,18 @@ Data the user explicitly starts recording, such as Wi-Fi packet captures and LoR
 _Avoid_: dump, log
 
 **Storage Warning**:
-The Notification raised once per boot when the SD card passes 80% full. Selecting it opens Storage Clean-up.
+The Notification raised once per boot when the SD card passes 80% full. It points at the Storage App, where Maintenance holds Storage Clean-up.
 
 **Storage Clean-up**:
-The screen where the user deletes old Logs and Captures by category and age, with a preview of the space freed. Notes are never offered for deletion.
+The screen where the user deletes old Logs and Captures by category and age, with a preview of the space freed. Notes are never offered for deletion. It lives in the Storage App, under Maintenance.
+
+**Storage App**:
+The App that browses the SD card: folders and files, a clipboard for one item at a time (copy, cut, paste), rename, delete, new folder, and a viewer for each kind of file the firmware writes. The top-level folders, `/gemini/cache` and files being written are read-only.
+_Avoid_: file manager, Files, explorer
+
+**Maintenance**:
+The part of the Storage App that deletes in bulk: the card's usage, Storage Clean-up and erasing the card. Reached through a warning.
+_Avoid_: Settings > Storage
 
 **Firmware Update**:
 Installing a new firmware image without a USB cable: pushed over Wi-Fi from the developer's PC, or read from the SD card.
diff --git a/README.md b/README.md
index c9ae822..fa7cae7 100644
--- a/README.md
+++ b/README.md
@@ -82,6 +82,31 @@ On a page, `b` bookmarks it, `s` saves it to the SD card to read offline (a non-
 
 The LoRa Scanner (docs/milestones/M3.md) listens with the Cap's radio and **never transmits**. The Sniffer lists what it hears, newest first: time, RSSI, SNR, and for Meshtastic packets the sender and receiver (their last 4 hex digits) and hops. Enter shows a packet's details: the Meshtastic header (which is never encrypted) and a hex dump. `p` picks one of the 7 Meshtastic presets allowed in EU868 (LongFast by default), `c` starts or stops a Capture: a pcap file with LoRaTap headers in `/captures/lora/`, for Wireshark. A Capture keeps recording with the App closed; otherwise the radio sleeps when the App isn't open. Tab switches to **Sweep**: the signal strength across 863–870 MHz in 100 kHz steps, as bars with peak hold and a waterfall, with the Sniffer's frequency marked; the Sniffer is paused meanwhile and picks up where it was. The GNSS receiver on the same Cap raises the radio's noise floor by 8 dB while it runs: Settings > "Pause GNSS for LoRa" (off by default) puts it in standby while the radio listens, except during a Track. The Status Bar shows `L` while the radio listens (bright for a moment on each packet), `SW` while sweeping, and `CAP` while capturing.
 
+## Storage
+
+The Storage App (docs/milestones/F1.md) shows what's on the SD card: each folder's entries with their size and date, folders first. Enter opens a folder, Back goes up; `s` sorts by name, date or size. It works on one item at a time, with a clipboard:
+
+| Key | Does |
+|---|---|
+| `c` / `x` | Copies or cuts the selected file or folder; the footer shows what `v` would paste |
+| `v` | Pastes it into the folder shown. A copy next to its original is named `name (2).txt`; anything in the way is asked about first |
+| `r` | Renames |
+| `d` | Deletes, after saying what's inside: "Delete saved and its 42 files (1.2 MB)?" |
+| `n` | Makes a folder |
+| `i` | Details: type, exact size, date, and why an item is read-only if it is |
+
+A copy runs in the background of the card (about 400 KB a second) in short turns, so Logs and Captures keep being written; it shows its progress, Back cancels it and takes back what was copied, and each file's size is checked afterwards. Three things can't be changed: the top-level folders the firmware keeps its files in (what's inside them can), `/gemini/cache`, and any file being written right now (today's IRC Logs, a Track or a Capture being recorded). The App says why when it refuses. A folder with more than 256 entries shows the first 256 by name and says so.
+
+Enter on a file opens it by type; Tab switches to the same file as a hex dump or as text:
+
+- **Text** (`.txt`, `.log`, `.gmi`, `.csv`, and anything that looks like text): only the screen's worth is read from the card, so a file of any size opens at once. Logs open at the end. Up and Down move a line, Left and Right a page, `t` and `b` go to the top and the end.
+- **Captures** (`.pcap`): the packets as the LoRa Scanner lists them; Enter shows one with its Meshtastic header and bytes.
+- **Tracks** (`.gpx`): the number of points, the start, the duration and the distance.
+- **Update Files** (`.ota`): the version, and whether the file would install: it's checked as an install checks it (signature and contents) without writing anything. Enter then installs it.
+- **Anything else:** a hex dump.
+
+At the top of the card the last row, **Maintenance** (also `m`), holds the card's usage, Storage Clean-up and "Erase SD card", behind a warning: those delete for good. It replaces Settings > Storage.
+
 ## Development aids
 
 `scripts/serial_log.sh [seconds] [command…]` records the serial output, and can send commands to the firmware first. For example, `scripts/serial_log.sh 30 short sleep:12 burst` sets short screen timeouts, waits 12 s, then sends a burst of Toasts.
@@ -98,6 +123,7 @@ The LoRa Scanner (docs/milestones/M3.md) listens with the Cap's radio and **neve
 | `log <text>` | Appends a line to a test IRC Log (`/irc/dev/#test/<date>.log`) |
 | `sd card` | What the SD card says it is: type, size, and its identity register (maker, name, revision, serial, date) |
 | `sd list` | Lists the files of each Storage Clean-up category |
+| `sd fill <folder> <count>` | Debug Builds: makes that many small files in a folder, to test a crowded one |
 | `cat <path>` | Prints the first ~1.2 KB of a file on the SD card |
 | `irc start` | Starts the IRC Service (normally done by opening the IRC App) |
 | `irc stop` | Stops it, as `/quit` does: QUIT if connected, no more retries, and the App stays disconnected until you type |
@@ -111,7 +137,8 @@ The LoRa Scanner (docs/milestones/M3.md) listens with the Cap's radio and **neve
 | `net` | Bytes each network service has read and written since boot |
 | `reboot` / `boot other` | Restart, or restart into the other app slot (a manual Rollback) |
 | `log level <0-5>` | ESP-IDF log level |
-| `ls [folder]` / `rm <path>` | Lists a folder of the SD card, or deletes a file |
+| `ls [folder]` / `du <path>` | Lists a folder of the SD card with sizes and dates, or counts the files and bytes under a path |
+| `cp [-f] <from> <to>` / `mv [-f] <from> <to>` / `rm <path>` / `mkdir <path>` / `cancel` | What the Storage App does, with its rules: copy (folders too), move or rename, delete (a folder with what's in it), new folder. `-f` replaces a file that's in the way; a tab separates paths that hold spaces; `cancel` stops a copy or a delete |
 | `install <path>` | Update from SD with that `.ota` file, as Settings → Firmware does |
 | `lora probe` | Finds the radio: chip, oscillator, antenna switch, DIO1 interrupt, noise floor |
 | `lora status` | Radio settings, who's listening, packet and error counters, noise floor, task stack |
diff --git a/docs/milestones/F1.md b/docs/milestones/F1.md
index ef6a44c..46b6a4c 100644
--- a/docs/milestones/F1.md
+++ b/docs/milestones/F1.md
@@ -1,6 +1,6 @@
 # F1 — Files and Notes
 
-**Status:** in progress (branch `f1`): the Storage App (issue #3) is being built. Notes (#19) and the card as a USB drive (#1) come after.
+**Status:** in progress (branch `f1`): the Storage App (issue #3) is built and checked on the device, not merged yet. Notes (#19) and the card as a USB drive (#1) come after.
 
 **Goal:** get at what's on the SD card from the device itself: browse it, look inside the files the firmware writes, copy, move, rename and delete, and keep notes. A side milestone, like G1 and S1; Files and Notes were M3's original second half (Q30, Q89).
 
@@ -34,7 +34,7 @@ Until now the card could be looked at only through the Debug Console (`ls`, `get
 - A file can be copied, moved, renamed and deleted, and a folder too; a new folder can be made. Each destructive action asks first; a copy shows progress and can be cancelled.
 - The read-only rules of Q130 hold, with a reason given when something is refused.
 - Each viewer of Q134 opens its type, and a 1 MB text file scrolls without loading whole.
-- Maintenance shows the card's usage and does what Settings > Storage did, behind its warning; Settings no longer has a Storage row; the Storage Warning opens the App's Maintenance.
+- Maintenance shows the card's usage and does what Settings > Storage did, behind its warning; Settings no longer has a Storage row; the Storage Warning points at the Storage App.
 - A file written with only a GNSS Fix (no Wi-Fi) is dated correctly.
 - Free heap stays above the floors with the App open, Wi-Fi and IRC on TLS.
 
@@ -46,3 +46,41 @@ Until now the card could be looked at only through the Debug Console (`ls`, `get
 4. **Maintenance:** usage, Clean-up and Erase moved in from Settings, with the warning.
 5. **Viewers:** text, hex, `.pcap`, `.gpx`, `.ota`.
 6. **Checks on the device**, recorded here.
+
+### As built
+
+- **`FileOps`** (`src/services/file_ops`) does the card's work for the App and for the console alike: list, count, copy, move, delete, new folder. One operation at a time on the storage task, **in turns of about 150 ms** that queue themselves again, so Log lines and a Capture are written in between. The rules of Q130 are checked there, whoever asks.
+- **A listing reads the folder straight from FatFs.** Through the Arduino `File`, every entry was looked up by name again for its size and again for its date: 329 entries took over two seconds. One pass now, and it's there before the screen has redrawn. Counting, copying and deleting still walk with `File`; they show progress and can be stopped.
+- **A copy shows its progress in a box in the App**, not a Toast (Q133): it has a bar and says Back cancels. A cancelled or failed copy deletes what it had written. The copy gets today's date, like `cp`.
+- **The viewers** (`src/apps/file_viewer`, models in `lib/files`): text through `TextPager`, which reads about a kilobyte around the screen and wraps at spaces, 38 columns; going back a line wraps the paragraph before again, so a file reads the same in both directions. A `.pcap`, a `.gpx` and an `.ota` are read through once by a storage job, in the same 150 ms turns. An Update File is fed to the installer's own parser with a sink that writes nothing, so "would it install" is the same answer an install gives.
+- **Tab** in a viewer shows the same file as hex, or as text (not in Q134).
+- **Maintenance** is the last row at the top of the card, and `m` anywhere in the App. It's the old Settings > Storage page behind a dialog.
+- **The Storage Warning** was only ever a Toast; "selecting it opens Storage Clean-up" (CONTEXT.md) was never built. It now reads "SD card over 80% full: see Storage".
+- **Console:** `cp`, `mv`, `mkdir` (Q138), and `rm` and `du` through the same code, so `rm` now takes folders and follows the rules; `ls` shows dates. Debug Builds: `sd fill <folder> <count>` makes test files.
+
+### Checks on the device (2026-10-06, v0.8.1-2 Debug Build)
+
+All in a scratch folder, `/f1test`, removed afterwards.
+
+| Check | Result |
+|---|---|
+| Host tests | 424 pass (411 before the viewers' models) |
+| Browsing | Folders first, sizes and dates, the three sorts; a 300-file and a 329-file folder show "first 256 of 300" and "of 329" |
+| New folder, rename, copy, cut and paste, delete | Each works on a file and on a folder; a copy next to its original is named `(2)`; a name in the way asks "Replace it?" |
+| A folder of 11 files, 8.4 MB, copied | 19.4 s, 435 KB/s, the bar moving; two Log lines queued meanwhile were written |
+| The same copy cancelled at 1.8 MB | "Cancelled: nothing was copied", and nothing was left behind |
+| Delete | 341 files in 9.7 s; the dialog had counted them first |
+| Read-only rules | `/irc`, `/gnss` (top-level folders), `/`, `/gemini/cache` and a folder made inside it, a folder into itself, a name with `:`; a Capture being recorded and the folder holding it; a folder under `/irc` while IRC runs. Each refused with its reason; the Capture could still be copied |
+| Text | A 1 MB log opens at its last line at once; top, pages, lines; a file without an extension that looks like text opens as text |
+| Hex | A 5 KB binary file; Tab from any other viewer |
+| `.pcap` | A LoRa Capture: 3 packets as the Scanner lists them, Enter shows the Meshtastic header and bytes |
+| `.gpx` | 400 points: start, 33 min 15 s, 4.68 km; Tab shows the text |
+| `.ota` | A signed file: version, "intact", "older than what's running", Enter asks to install (not confirmed). A tampered one: "image corrupted (hash mismatch)" |
+| Maintenance | The warning, then usage, Clean-up's categories and Erase (not run) |
+| Date with GNSS only | NTP pointed at an address that doesn't answer, restart: the Clock came from the Fix, and a folder made then is dated 2026-10-06 08:39. A Track from the day before, written the same way by v0.8.1, shows "-" |
+| Memory | IRC connected, the App open on 256 entries: 61 KB free (70 KB before opening). Lowest since boot 29.7 KB, during IRC's TLS handshake |
+| Stacks | `storage` 3.1 KB free of 6 KB at worst, `loopTask` 1.5 KB |
+
+**Not checked by hand:** how the keys feel on the device itself; everything above was driven through the Debug Console's `key` command and screenshots.
+
+**One slip during the checks:** a scripted key sequence ran in the wrong folder and renamed `/gemini/saved` to `saved2`, then copied it to the top of the card. Both were put right at once (renamed back, the copy deleted; 7 files, 53,798 bytes, as before).
diff --git a/lib/apps_model/src/settings_menu.cpp b/lib/apps_model/src/settings_menu.cpp
index 176246e..b1fab38 100644
--- a/lib/apps_model/src/settings_menu.cpp
+++ b/lib/apps_model/src/settings_menu.cpp
@@ -23,7 +23,6 @@ const RowDef kRows[] = {
     {Row::Gnss, Kind::Toggle, "GNSS"}, {Row::GnssQuiet, Kind::Toggle, "Pause GNSS for LoRa"},
     {Row::Coordinates, Kind::Toggle, "Coordinates"},
     {Row::ProbeMacs, Kind::Toggle, "Probe MACs"}, {Row::Wifi, Kind::Page, "Wi-Fi"},
-    {Row::Storage, Kind::Page, "Storage"},
     {Row::Firmware, Kind::Page, "Firmware"},
     {Row::About, Kind::Page, "About"},
 };
diff --git a/lib/apps_model/src/settings_menu.h b/lib/apps_model/src/settings_menu.h
index 176cea9..09eb0a4 100644
--- a/lib/apps_model/src/settings_menu.h
+++ b/lib/apps_model/src/settings_menu.h
@@ -11,7 +11,7 @@ namespace roro {
 // values, choice lists and validation messages. Rendering and navigation live in the App.
 class SettingsMenu {
    public:
-    enum class Row { LongName, ShortName, Region, Timezone, Brightness, DimTimeout, OffTimeout, Sound, Gnss, GnssQuiet, Coordinates, ProbeMacs, Wifi, Storage, Firmware, About };
+    enum class Row { LongName, ShortName, Region, Timezone, Brightness, DimTimeout, OffTimeout, Sound, Gnss, GnssQuiet, Coordinates, ProbeMacs, Wifi, Firmware, About };
     enum class Kind { Text, Choice, Toggle, Slider, Page };
 
     explicit SettingsMenu(Settings& settings) : settings_(settings) {}
diff --git a/lib/files/src/file_list.cpp b/lib/files/src/file_list.cpp
index c8fdb42..a5b8f29 100644
--- a/lib/files/src/file_list.cpp
+++ b/lib/files/src/file_list.cpp
@@ -128,4 +128,10 @@ std::string rowDetail(bool folder, uint32_t size, uint32_t modified) {
     return sizeText(size) + "  " + (stamp == "-" ? stamp : stamp.substr(0, 10));
 }
 
+std::string fitName(const std::string& name, size_t maxChars) {
+    if (name.size() <= maxChars || maxChars < 8) return name.substr(0, maxChars);
+    size_t tail = std::min<size_t>(6, maxChars / 3), head = maxChars - tail - 2;
+    return name.substr(0, head) + ".." + name.substr(name.size() - tail);
+}
+
 }  // namespace roro::files
diff --git a/lib/files/src/file_list.h b/lib/files/src/file_list.h
index cf9f0a7..cd7eb69 100644
--- a/lib/files/src/file_list.h
+++ b/lib/files/src/file_list.h
@@ -48,6 +48,8 @@ class FileList {
 // What a row shows on the right (Q129): "folder", or "1.2 KB  2026-10-05". A file dated before
 // 2020 was written before the clock was set: "-" (Q137). Local time.
 std::string rowDetail(bool folder, uint32_t size, uint32_t modified);
-std::string formatStamp(uint32_t modified);  // "2026-10-05 20:00", or "-"
+std::string formatStamp(uint32_t modified);
+// A name cut to `maxChars` for a row, from the middle: the start and the extension stay readable.
+std::string fitName(const std::string& name, size_t maxChars);  // "2026-10-05 20:00", or "-"
 
 }  // namespace roro::files
diff --git a/lib/files/src/file_views.cpp b/lib/files/src/file_views.cpp
new file mode 100644
index 0000000..fdaa120
--- /dev/null
+++ b/lib/files/src/file_views.cpp
@@ -0,0 +1,143 @@
+#include "file_views.h"
+
+#include <cstdio>
+#include <cstdlib>
+#include <cstring>
+
+#include "file_list.h"
+#include "track.h"
+
+namespace roro::files {
+
+std::string hexRow(uint32_t offset, const uint8_t* data, size_t len) {
+    char head[8];
+    std::snprintf(head, sizeof head, "%05X", static_cast<unsigned>(offset));
+    std::string row = head, text;
+    for (size_t i = 0; i < 8; i++) {
+        if (i % 2 == 0) row += ' ';
+        char hex[3] = "  ";
+        if (i < len) {
+            std::snprintf(hex, sizeof hex, "%02x", data[i]);
+            text += data[i] >= 0x20 && data[i] < 0x7F ? static_cast<char>(data[i]) : '.';
+        }
+        row += hex;
+    }
+    return row + "  " + text;
+}
+
+namespace {
+// Days since 1970-01-01 (Howard Hinnant's days_from_civil): no timegm() everywhere.
+int64_t daysFromCivil(int y, int m, int d) {
+    y -= m <= 2;
+    int64_t era = (y >= 0 ? y : y - 399) / 400;
+    int yoe = static_cast<int>(y - era * 400);
+    int doy = (153 * (m + (m > 2 ? -3 : 9)) + 2) / 5 + d - 1;
+    int doe = yoe * 365 + yoe / 4 - yoe / 100 + doy;
+    return era * 146097 + doe - 719468;
+}
+
+bool attribute(const std::string& element, const char* name, double& out) {
+    size_t at = element.find(name);
+    if (at == std::string::npos) return false;
+    const char* from = element.c_str() + at + std::strlen(name);
+    char* end = nullptr;
+    out = std::strtod(from, &end);
+    return end != from;
+}
+}  // namespace
+
+void GpxSummary::point(const std::string& element) {
+    double lat, lon;
+    if (!attribute(element, "lat=\"", lat) || !attribute(element, "lon=\"", lon)) return;
+    if (points_ > 0) meters_ += gnss::distanceMeters(lat_, lon_, lat, lon);
+    lat_ = lat;
+    lon_ = lon;
+    points_++;
+    size_t at = element.find("<time>");
+    int y, mo, d, h, mi, s;
+    if (at != std::string::npos && std::sscanf(element.c_str() + at + 6, "%d-%d-%dT%d:%d:%d", &y, &mo, &d, &h, &mi, &s) == 6) {
+        int64_t t = daysFromCivil(y, mo, d) * 86400 + h * 3600 + mi * 60 + s;
+        if (first_ == 0) first_ = t;
+        last_ = t;
+    }
+}
+
+void GpxSummary::feed(const char* data, size_t len) {
+    carry_.append(data, len);
+    size_t done = 0;
+    for (;;) {
+        size_t open = carry_.find("<trkpt", done);
+        if (open == std::string::npos) {
+            // Nothing begun, except perhaps the first letters of a tag at the very end.
+            done = carry_.size() > 6 ? carry_.size() - 6 : done;
+            break;
+        }
+        size_t close = carry_.find("</trkpt>", open);
+        size_t next = carry_.find("<trkpt", open + 6);  // a point with nothing inside: <trkpt .../>
+        if (close == std::string::npos && next == std::string::npos) {
+            done = open;
+            break;
+        }
+        size_t end = close != std::string::npos && (next == std::string::npos || close < next) ? close + 8 : next;
+        point(carry_.substr(open, end - open));
+        done = end;
+    }
+    carry_.erase(0, done);
+    if (carry_.size() > 2048) carry_.erase(0, carry_.size() - 6);  // not a GPX point: don't keep it
+}
+
+std::string formatDuration(int64_t seconds) {
+    char s[24];
+    if (seconds < 60) std::snprintf(s, sizeof s, "%d s", static_cast<int>(seconds));
+    else if (seconds < 3600) std::snprintf(s, sizeof s, "%d min %02d s", static_cast<int>(seconds / 60), static_cast<int>(seconds % 60));
+    else std::snprintf(s, sizeof s, "%d h %02d min", static_cast<int>(seconds / 3600), static_cast<int>(seconds % 3600 / 60));
+    return s;
+}
+
+std::vector<std::string> GpxSummary::lines() const {
+    std::vector<std::string> out;
+    out.push_back(std::to_string(points_) + (points_ == 1 ? " point" : " points"));
+    if (first_ > 0) {
+        out.push_back("Started " + formatStamp(static_cast<uint32_t>(first_)));
+        out.push_back("Lasted " + formatDuration(last_ - first_));
+    }
+    char s[32];
+    if (meters_ < 1000) std::snprintf(s, sizeof s, "Distance %.0f m", meters_);
+    else std::snprintf(s, sizeof s, "Distance %.2f km", meters_ / 1000);
+    out.push_back(s);
+    return out;
+}
+
+namespace {
+uint32_t le32(const uint8_t* p) { return p[0] | p[1] << 8 | p[2] << 16 | static_cast<uint32_t>(p[3]) << 24; }
+}  // namespace
+
+PcapHeader parsePcapHeader(const uint8_t* data, size_t len) {
+    PcapHeader h;
+    if (len < kPcapHeaderSize || le32(data) != 0xA1B2C3D4) return h;  // little-endian, microseconds: what we write
+    h.ok = true;
+    h.linkType = le32(data + 20);
+    return h;
+}
+
+bool parsePcapRecord(const uint8_t* data, size_t len, PcapRecord& out) {
+    if (len < kPcapRecordSize) return false;
+    out.seconds = le32(data);
+    out.micros = le32(data + 4);
+    out.length = le32(data + 8);
+    return out.length <= 65535;
+}
+
+bool parseLoraTap(const uint8_t* d, size_t len, lora::RxInfo& out) {
+    if (len < lora::kLoraTapSize || d[0] != 0) return false;
+    out.frequencyHz = static_cast<uint32_t>(d[4]) << 24 | d[5] << 16 | d[6] << 8 | d[7];
+    out.bandwidthKHz = d[8] * 125.0f;
+    out.spreadingFactor = d[9];
+    out.rssi = d[10] - 139.0f;
+    out.noiseFloor = d[12] - 139.0f;
+    out.snr = static_cast<int8_t>(d[13]) / 4.0f;
+    out.syncWord = d[14];
+    return true;
+}
+
+}  // namespace roro::files
diff --git a/lib/files/src/file_views.h b/lib/files/src/file_views.h
new file mode 100644
index 0000000..7742736
--- /dev/null
+++ b/lib/files/src/file_views.h
@@ -0,0 +1,57 @@
+#pragma once
+
+#include <cstddef>
+#include <cstdint>
+#include <string>
+#include <vector>
+
+#include "loratap.h"
+
+namespace roro::files {
+
+// What the Storage App's viewers show of the files the firmware writes (F1, Q134).
+
+// One row of a hex dump, eight bytes: "00010 4865 6c6c 6f2c 2077  Hello, w".
+std::string hexRow(uint32_t offset, const uint8_t* data, size_t len);
+
+// A Track (.gpx) read a piece at a time: its points, when it started and ended, how far it went.
+class GpxSummary {
+   public:
+    void feed(const char* data, size_t len);
+
+    uint32_t points() const { return points_; }
+    int64_t start() const { return first_; }  // UTC seconds, 0 if no point carried a time
+    int64_t end() const { return last_; }
+    double meters() const { return meters_; }
+    std::vector<std::string> lines() const;  // for the screen
+
+   private:
+    void point(const std::string& element);
+
+    std::string carry_;  // the part of a point cut by the end of a piece
+    uint32_t points_ = 0;
+    int64_t first_ = 0, last_ = 0;
+    double meters_ = 0, lat_ = 0, lon_ = 0;
+};
+
+// "1 h 02 min", "4 min 10 s", "12 s".
+std::string formatDuration(int64_t seconds);
+
+// A Capture (.pcap): the file's header, then one record after another.
+struct PcapHeader {
+    bool ok = false;
+    uint32_t linkType = 0;  // 270: LoRaTap, what the LoRa Scanner writes
+};
+constexpr size_t kPcapHeaderSize = 24, kPcapRecordSize = 16;
+constexpr uint32_t kLinkLoraTap = 270;
+PcapHeader parsePcapHeader(const uint8_t* data, size_t len);
+
+struct PcapRecord {
+    uint32_t seconds = 0, micros = 0, length = 0;  // length: the bytes that follow in the file
+};
+bool parsePcapRecord(const uint8_t* data, size_t len, PcapRecord& out);  // false: not a record, stop there
+
+// The LoRaTap header a packet starts with; false if `len` is too short for one.
+bool parseLoraTap(const uint8_t* data, size_t len, lora::RxInfo& out);
+
+}  // namespace roro::files
diff --git a/lib/files/src/text_pager.cpp b/lib/files/src/text_pager.cpp
new file mode 100644
index 0000000..d4074c0
--- /dev/null
+++ b/lib/files/src/text_pager.cpp
@@ -0,0 +1,121 @@
+#include "text_pager.h"
+
+#include <algorithm>
+
+namespace roro::files {
+
+TextPager::TextPager(ReadAt read, uint32_t size, int cols, int rows)
+    : read_(std::move(read)), size_(size), cols_(std::max(1, cols)), rows_(std::max(1, rows)) {}
+
+const uint8_t* TextPager::bytes(uint32_t at, size_t& len) {
+    len = 0;
+    if (at >= size_) return nullptr;
+    bool cached = at >= cacheAt_ && at < cacheAt_ + cache_.size();
+    // Wanted: a line's worth ahead, unless the cache already reaches the end of the file.
+    size_t ahead = cached ? cacheAt_ + cache_.size() - at : 0;
+    if (!cached || (ahead < kBlock / 4 && cacheAt_ + cache_.size() < size_)) {
+        cacheAt_ = at - std::min<uint32_t>(at, kBlock / 2);  // room behind too: scrolling back is common
+        cache_.resize(std::min<uint32_t>(kBlock, size_ - cacheAt_));
+        cache_.resize(read_(cacheAt_, cache_.data(), cache_.size()));
+        if (at >= cacheAt_ + cache_.size()) return nullptr;  // the file got shorter, or the card failed
+    }
+    len = cacheAt_ + cache_.size() - at;
+    return cache_.data() + (at - cacheAt_);
+}
+
+int TextPager::byteAt(uint32_t at) {
+    size_t len;
+    const uint8_t* p = bytes(at, len);
+    return p ? *p : -1;
+}
+
+uint32_t TextPager::nextLine(uint32_t at, std::string* text) {
+    size_t len;
+    const uint8_t* p = bytes(at, len);
+    if (text) text->clear();
+    if (!p) return size_;
+    size_t end = len, next = len;  // the line is [0, end); the one after starts at `next`
+    int count = 0;
+    size_t lastSpace = 0;
+    for (size_t i = 0; i < len; i++) {
+        uint8_t b = p[i];
+        if (b == '\n') {
+            end = i;
+            next = i + 1;
+            break;
+        }
+        if ((b & 0xC0) == 0x80) continue;  // inside a UTF-8 character
+        if (count == cols_) {              // one character too many: wrap
+            if (b == ' ') end = i, next = i + 1;
+            else if (lastSpace > 0) end = lastSpace, next = lastSpace + 1;
+            else end = next = i;
+            break;
+        }
+        count++;
+        if (b == ' ') lastSpace = i;
+    }
+    if (text) {
+        size_t n = end > 0 && p[end - 1] == '\r' ? end - 1 : end;
+        text->reserve(n);
+        for (size_t i = 0; i < n; i++) text->push_back(p[i] == '\t' ? ' ' : (p[i] < 0x20 || p[i] == 0x7F) ? '.' : static_cast<char>(p[i]));
+    }
+    return at + static_cast<uint32_t>(std::max<size_t>(next, 1));
+}
+
+uint32_t TextPager::lineBefore(uint32_t at) {
+    if (at == 0) return 0;
+    at = std::min(at, size_);
+    // The paragraph the line before `at` belongs to starts after the newline before it. The byte
+    // just before `at` may be that line's own newline.
+    uint32_t from = at - 1;
+    if (from > 0 && byteAt(from) == '\n') from--;
+    uint32_t limit = at > kLookBack ? at - kLookBack : 0, start = limit;
+    for (uint32_t i = from + 1; i-- > limit;) {
+        if (byteAt(i) == '\n' && i < at - 1) {
+            start = i + 1;
+            break;
+        }
+    }
+    // No newline that near: any character boundary will do as a place to wrap from.
+    while (start > 0 && start < at && (byteAt(start) & 0xC0) == 0x80) start++;
+    for (uint32_t a = start;;) {
+        uint32_t next = nextLine(a, nullptr);
+        if (next >= at) return a;
+        a = next;
+    }
+}
+
+bool TextPager::atEnd() {
+    uint32_t a = top_;
+    for (int i = 0; i < rows_; i++) {
+        a = nextLine(a, nullptr);
+        if (a >= size_) return true;
+    }
+    return false;
+}
+
+void TextPager::down(int n) {
+    for (; n > 0 && !atEnd(); n--) top_ = nextLine(top_, nullptr);
+}
+
+void TextPager::up(int n) {
+    for (; n > 0 && top_ > 0; n--) top_ = lineBefore(top_);
+}
+
+void TextPager::toEnd() {
+    top_ = size_;
+    up(rows_);
+}
+
+std::vector<std::string> TextPager::lines() {
+    std::vector<std::string> out;
+    uint32_t a = top_;
+    for (int i = 0; i < rows_ && a < size_; i++) {
+        std::string text;
+        a = nextLine(a, &text);
+        out.push_back(std::move(text));
+    }
+    return out;
+}
+
+}  // namespace roro::files
diff --git a/lib/files/src/text_pager.h b/lib/files/src/text_pager.h
new file mode 100644
index 0000000..fc31f91
--- /dev/null
+++ b/lib/files/src/text_pager.h
@@ -0,0 +1,50 @@
+#pragma once
+
+#include <cstddef>
+#include <cstdint>
+#include <functional>
+#include <string>
+#include <vector>
+
+namespace roro::files {
+
+// A text file of any size, shown a screen at a time (F1, Q134): only the part on screen is read,
+// through `read`, about a kilobyte at once. Lines wrap at spaces, `cols` characters wide. Going
+// back a line means finding where the paragraph before started and wrapping it again, so a file
+// reads the same whichever way it was scrolled.
+class TextPager {
+   public:
+    // Reads up to `len` bytes at `offset`; returns how many it got.
+    using ReadAt = std::function<size_t(uint32_t offset, uint8_t* into, size_t len)>;
+
+    TextPager(ReadAt read, uint32_t size, int cols, int rows);
+
+    void toStart() { top_ = 0; }
+    void toEnd();  // the last line at the bottom of the screen
+    void down(int lines = 1);
+    void up(int lines = 1);
+
+    std::vector<std::string> lines();  // what's on screen: tabs as spaces, control characters as dots
+    uint32_t top() const { return top_; }
+    uint32_t size() const { return size_; }
+    bool atEnd();  // the file's last line is on screen
+    int percent() const { return size_ ? static_cast<int>(static_cast<uint64_t>(top_) * 100 / size_) : 0; }
+
+   private:
+    static constexpr size_t kBlock = 1024;       // read at once
+    static constexpr uint32_t kLookBack = 1024;  // how far back a paragraph's start is looked for
+
+    const uint8_t* bytes(uint32_t at, size_t& len);  // what's cached from `at` on
+    int byteAt(uint32_t at);                         // -1 past the end
+    uint32_t nextLine(uint32_t at, std::string* text);  // where the line after the one at `at` starts
+    uint32_t lineBefore(uint32_t at);
+
+    ReadAt read_;
+    uint32_t size_;
+    int cols_, rows_;
+    uint32_t top_ = 0;
+    std::vector<uint8_t> cache_;
+    uint32_t cacheAt_ = 0;
+};
+
+}  // namespace roro::files
diff --git a/lib/services/src/storage_monitor.cpp b/lib/services/src/storage_monitor.cpp
index e09350f..9b7f691 100644
--- a/lib/services/src/storage_monitor.cpp
+++ b/lib/services/src/storage_monitor.cpp
@@ -24,7 +24,7 @@ void StorageMonitor::update(bool present, uint64_t totalBytes, uint64_t usedByte
 
     if (next.present && next.level >= 80 && !warned_) {
         warned_ = true;
-        bus_.publish(Event::withText(EventType::Notification, "SD card over 80% full",
+        bus_.publish(Event::withText(EventType::Notification, "SD card over 80% full: see Storage",
                                      static_cast<int32_t>(NotificationLevel::Warning)));
     }
 }
diff --git a/src/apps/file_viewer.cpp b/src/apps/file_viewer.cpp
new file mode 100644
index 0000000..c417666
--- /dev/null
+++ b/src/apps/file_viewer.cpp
@@ -0,0 +1,458 @@
+#include "file_viewer.h"
+
+#include <Arduino.h>
+#include <SD.h>
+
+#include <algorithm>
+#include <atomic>
+#include <cstdio>
+#include <ctime>
+
+#include "cleanup_plan.h"
+#include "file_list.h"
+#include "file_names.h"
+#include "file_views.h"
+#include "meshtastic_presets.h"
+#include "packet_view.h"
+#include "platform/ota_device.h"
+#include "ui/fonts.h"
+#include "ui/widgets.h"
+#include "update_parser.h"
+#include "version.h"
+
+namespace roro {
+
+namespace {
+constexpr uint32_t kSliceMs = 150;      // like the Storage App's operations: the Logs get their turn
+constexpr size_t kPiece = 1024;
+constexpr size_t kMaxPackets = 1000;    // their places in the file, 4 KB
+constexpr size_t kMaxPacketBytes = 271;  // LoRaTap and the longest LoRa packet
+
+// Checks an Update File as an install would, writing nothing.
+struct NoSink : UpdateSink {
+    bool begin(size_t) override { return true; }
+    bool write(const uint8_t*, size_t) override { return true; }
+    bool finish() override { return true; }
+    void abort() override {}
+};
+
+std::string clockTime(uint32_t utcSeconds) {
+    time_t t = static_cast<time_t>(utcSeconds);
+    struct tm local;
+    localtime_r(&t, &local);
+    char s[12];
+    std::snprintf(s, sizeof s, "%02d:%02d:%02d", local.tm_hour, local.tm_min, local.tm_sec);
+    return s;
+}
+}  // namespace
+
+struct FileViewer::Scan {
+    std::atomic<bool> done{false}, stop{false};
+    std::atomic<int> percent{0};
+    Mode what = Mode::Gpx;
+    std::string path;
+    // Touched by the storage task until `done`, by the viewer after.
+    fs::File file;
+    bool opened = false;
+    uint32_t at = 0, size = 0;
+    std::string error;
+    files::GpxSummary gpx;
+    files::PcapHeader pcap;
+    std::vector<uint32_t> packets;  // where each record starts
+    bool morePackets = false;
+    std::unique_ptr<EcdsaVerifier> verifier;
+    NoSink sink;
+    std::unique_ptr<UpdateParser> parser;
+    std::string version;
+    bool genuine = false, older = false;
+
+    bool slice();  // true when there's nothing more to read
+    static void run(StorageService* storage, std::shared_ptr<Scan> self) {
+        bool over = self->stop || self->slice();
+        if (over) {
+            if (self->file) self->file.close();
+            self->parser.reset();
+            self->verifier.reset();
+            self->done = true;
+        } else {
+            storage->runJob([storage, self]() { run(storage, self); });
+        }
+    }
+};
+
+bool FileViewer::Scan::slice() {
+    uint32_t t0 = millis();
+    if (!opened) {
+        opened = true;
+        file = SD.open(path.c_str(), FILE_READ);
+        if (!file) {
+            error = "The card refused to open it";
+            return true;
+        }
+        size = static_cast<uint32_t>(file.size());
+        if (what == Mode::Ota) {
+            verifier.reset(new EcdsaVerifier());
+            parser.reset(new UpdateParser(*verifier, sink, EspOtaSink().capacity(), versionString()));
+        }
+    }
+    std::unique_ptr<uint8_t[]> piece(new uint8_t[kPiece]);
+    while (millis() - t0 < kSliceMs) {
+        if (stop) return true;
+        if (what == Mode::Pcap) {
+            if (at == 0) {
+                int n = file.read(piece.get(), files::kPcapHeaderSize);
+                pcap = files::parsePcapHeader(piece.get(), n < 0 ? 0 : n);
+                if (!pcap.ok) {
+                    error = "Not a pcap file this viewer reads";
+                    return true;
+                }
+                at = files::kPcapHeaderSize;
+            }
+            files::PcapRecord r;
+            if (!file.seek(at)) return true;
+            int n = file.read(piece.get(), files::kPcapRecordSize);
+            if (n < 0 || !files::parsePcapRecord(piece.get(), n, r) || at + files::kPcapRecordSize + r.length > size) return true;
+            if (packets.size() >= kMaxPackets) {
+                morePackets = true;
+                return true;
+            }
+            packets.push_back(at);
+            at += files::kPcapRecordSize + r.length;
+            continue;
+        }
+        int n = file.read(piece.get(), kPiece);
+        if (n <= 0) break;
+        at += n;
+        percent = size ? static_cast<int>(static_cast<uint64_t>(at) * 100 / size) : 100;
+        if (what == Mode::Gpx) {
+            gpx.feed(reinterpret_cast<const char*>(piece.get()), n);
+        } else {
+            parser->feed(piece.get(), n);
+            if (parser->state() == UpdateParser::State::Failed) break;
+        }
+    }
+    if (at < size && !(parser && parser->state() == UpdateParser::State::Failed) && millis() - t0 >= kSliceMs) return false;
+    if (parser) {
+        genuine = parser->end();
+        version = parser->version();
+        older = parser->isDowngrade();
+        error = parser->error();
+    }
+    return true;
+}
+
+size_t FileViewer::readAt(uint32_t offset, uint8_t* into, size_t len) {
+    size_t got = 0;
+    auto file = file_;
+    std::string path = path_;
+    storage_.runAndWait([&, file, path]() {
+        if (!*file) *file = SD.open(path.c_str(), FILE_READ);
+        if (!*file || !file->seek(offset)) return;
+        int n = file->read(into, len);
+        got = n < 0 ? 0 : n;
+    });
+    return got;
+}
+
+void FileViewer::open(const std::string& path, uint32_t size) {
+    close();
+    path_ = path;
+    size_ = size;
+    file_ = std::make_shared<fs::File>();
+    std::string name = files::baseName(path);
+    files::FileKind kind = files::kindOf(name);
+    if (kind == files::FileKind::Unknown) {  // what do its first bytes look like?
+        uint8_t head[256];
+        size_t n = readAt(0, head, sizeof head);
+        kind = files::looksLikeText(head, n) ? files::FileKind::Text : files::FileKind::Unknown;
+    }
+    switch (kind) {
+        case files::FileKind::Text: base_ = Mode::Text; break;
+        case files::FileKind::Gpx: base_ = Mode::Gpx; break;
+        case files::FileKind::Pcap: base_ = Mode::Pcap; break;
+        case files::FileKind::Ota: base_ = Mode::Ota; break;
+        default: base_ = Mode::Hex; break;
+    }
+    pager_.reset(new files::TextPager([this](uint32_t offset, uint8_t* into, size_t len) { return readAt(offset, into, len); }, size_,
+                                      kCols, kRows));
+    if (files::opensAtEnd(name)) pager_->toEnd();
+    hexTop_ = 0;
+    show(base_);
+    if (base_ == Mode::Gpx || base_ == Mode::Pcap || base_ == Mode::Ota) startScan(base_);
+}
+
+void FileViewer::startScan(Mode mode) {
+    scan_ = std::make_shared<Scan>();
+    scan_->what = mode;
+    scan_->path = path_;
+    scanShown_ = false;
+    shownPercent_ = -1;
+    auto scan = scan_;
+    StorageService* storage = &storage_;
+    storage_.runJob([storage, scan]() { Scan::run(storage, scan); });
+}
+
+void FileViewer::close() {
+    if (scan_) scan_->stop = true;  // its job ends at the next piece and frees itself
+    scan_.reset();
+    if (file_) {
+        auto file = file_;
+        storage_.runJob([file]() {
+            if (*file) file->close();
+        });
+    }
+    file_.reset();
+    pager_.reset();
+    confirm_.reset();
+    std::vector<std::string>().swap(shown_);
+    std::vector<std::string>().swap(details_);
+    packets_.setCount(0);
+    rowsFrom_ = -1;
+}
+
+void FileViewer::show(Mode mode) {
+    mode_ = mode;
+    stale_ = true;
+    rowsFrom_ = -1;
+}
+
+std::string FileViewer::title() const { return files::fitName(files::baseName(path_), 24); }
+
+void FileViewer::scroll(int lines) {
+    if (mode_ == Mode::Text && pager_) {
+        if (lines > 0) pager_->down(lines);
+        else pager_->up(-lines);
+    } else if (mode_ == Mode::Hex) {
+        uint32_t rows = (size_ + 7) / 8, last = rows > static_cast<uint32_t>(kRows) ? rows - kRows : 0;
+        int64_t to = static_cast<int64_t>(hexTop_) + lines;
+        hexTop_ = static_cast<uint32_t>(std::clamp<int64_t>(to, 0, last));
+    }
+    stale_ = true;
+}
+
+void FileViewer::openPacket(int index) {
+    if (!scan_ || !scan_->done || index < 0 || index >= static_cast<int>(scan_->packets.size())) return;
+    uint8_t buf[files::kPcapRecordSize + kMaxPacketBytes];
+    size_t n = readAt(scan_->packets[index], buf, sizeof buf);
+    files::PcapRecord r;
+    if (!files::parsePcapRecord(buf, n, r)) return;
+    const uint8_t* body = buf + files::kPcapRecordSize;
+    size_t have = std::min<size_t>(r.length, n - files::kPcapRecordSize);
+    details_.clear();
+    char line[64];
+    lora::RxInfo rx;
+    bool tap = scan_->pcap.linkType == files::kLinkLoraTap && files::parseLoraTap(body, have, rx);
+    size_t skip = tap ? lora::kLoraTapSize : 0;
+    std::snprintf(line, sizeof line, "%s, %u bytes", clockTime(r.seconds).c_str(), static_cast<unsigned>(r.length - skip));
+    details_.push_back(line);
+    if (tap) {
+        std::snprintf(line, sizeof line, "%.0f dBm, SNR %.1f dB, noise %.0f", rx.rssi, rx.snr, rx.noiseFloor);
+        details_.push_back(line);
+        std::snprintf(line, sizeof line, "%.4f MHz, SF%u, %.0f kHz", rx.frequencyHz / 1e6, rx.spreadingFactor, rx.bandwidthKHz);
+        details_.push_back(line);
+        if (rx.syncWord == meshtastic::kSyncWord)
+            for (auto& l : lora::headerLines(body + skip, have - skip)) details_.push_back(l);
+    }
+    for (auto& l : lora::hexDump(body + skip, have - skip)) details_.push_back(l);
+    if (have < r.length) details_.push_back("(the first bytes only)");
+    detailsTop_ = 0;
+    mode_ = Mode::Packet;
+}
+
+bool FileViewer::onKey(const KeyEvent& e) {
+    if (confirm_) {
+        confirm_->onKey(e);
+        if (confirm_->result() == 1) update_.installFromSd(path_);
+        if (confirm_->result() != DialogModel::kPending) confirm_.reset();
+        return true;
+    }
+    if (mode_ == Mode::Packet) {
+        int last = std::max(0, static_cast<int>(details_.size()) - (kRows + 1));
+        if (e.key == Key::Up) detailsTop_ = std::max(0, detailsTop_ - 1);
+        else if (e.key == Key::Down) detailsTop_ = std::min(last, detailsTop_ + 1);
+        else if (e.key == Key::Back || e.key == Key::Select) mode_ = Mode::Pcap;
+        return true;
+    }
+    if (e.key == Key::Back) return false;
+    if (e.key == Key::Tab) {
+        // The file's own view, or what it's made of: text for a Track, bytes for the others.
+        if (mode_ != base_) show(base_);
+        else show(base_ == Mode::Hex || base_ == Mode::Gpx ? Mode::Text : Mode::Hex);
+        return true;
+    }
+    uint32_t ch = e.key == Key::Char ? e.ch : 0;
+    switch (mode_) {
+        case Mode::Text:
+        case Mode::Hex:
+            if (e.key == Key::Up) scroll(-1);
+            else if (e.key == Key::Down) scroll(1);
+            else if (e.key == Key::Left) scroll(-(kRows - 1));
+            else if (e.key == Key::Right) scroll(kRows - 1);
+            else if (ch == 't' || ch == 'T') {
+                if (pager_) pager_->toStart();
+                hexTop_ = 0;
+                stale_ = true;
+            } else if (ch == 'b' || ch == 'B') {
+                if (mode_ == Mode::Text && pager_) pager_->toEnd();
+                else scroll(INT32_MAX / 2);
+                stale_ = true;
+            }
+            break;
+        case Mode::Pcap:
+            if (e.key == Key::Up) packets_.up();
+            else if (e.key == Key::Down) packets_.down();
+            else if (e.key == Key::Left) packets_.pageUp();
+            else if (e.key == Key::Right) packets_.pageDown();
+            else if (e.key == Key::Select) openPacket(packets_.selected());
+            break;
+        case Mode::Ota:
+            if (e.key == Key::Select && scan_ && scan_->done && scan_->genuine) confirm_.reset(new DialogModel({"Cancel", "Install"}));
+            break;
+        default: break;
+    }
+    return true;
+}
+
+bool FileViewer::update(uint32_t) {
+    if (!scan_) return false;
+    if (scan_->done && !scanShown_) {
+        scanShown_ = true;
+        if (scan_->what == Mode::Pcap) packets_.setCount(static_cast<int>(scan_->packets.size()));
+        return true;
+    }
+    int percent = scan_->percent;
+    if (!scan_->done && percent != shownPercent_) {
+        shownPercent_ = percent;
+        return true;
+    }
+    return false;
+}
+
+void FileViewer::refresh() {
+    if (mode_ == Mode::Text && stale_ && pager_) {
+        shown_ = pager_->lines();
+        stale_ = false;
+    } else if (mode_ == Mode::Hex && stale_) {
+        uint8_t buf[kRows * 8];
+        size_t n = readAt(hexTop_ * 8, buf, sizeof buf);
+        shown_.clear();
+        for (size_t at = 0; at < n; at += 8) shown_.push_back(files::hexRow(hexTop_ * 8 + at, buf + at, std::min<size_t>(8, n - at)));
+        stale_ = false;
+    } else if (mode_ == Mode::Pcap && scan_ && scan_->done && rowsFrom_ != packets_.firstVisible()) {
+        // The rows on screen, read from the card once each time the list moves.
+        rowsFrom_ = packets_.firstVisible();
+        shown_.clear();
+        bool tap = scan_->pcap.linkType == files::kLinkLoraTap;
+        for (int i = rowsFrom_; i < rowsFrom_ + kRows && i < static_cast<int>(scan_->packets.size()); i++) {
+            uint8_t buf[files::kPcapRecordSize + kMaxPacketBytes];
+            size_t n = readAt(scan_->packets[i], buf, sizeof buf);
+            files::PcapRecord r;
+            lora::RxInfo rx;
+            if (!files::parsePcapRecord(buf, n, r)) {
+                shown_.push_back("(unreadable)");
+                continue;
+            }
+            const uint8_t* body = buf + files::kPcapRecordSize;
+            size_t have = std::min<size_t>(r.length, n - files::kPcapRecordSize);
+            if (tap && files::parseLoraTap(body, have, rx)) {
+                shown_.push_back(lora::row({body + lora::kLoraTapSize, have - lora::kLoraTapSize, rx.rssi, rx.snr, true,
+                                            rx.syncWord == meshtastic::kSyncWord},
+                                           clockTime(r.seconds)));
+            } else {
+                shown_.push_back(clockTime(r.seconds) + "  " + std::to_string(r.length) + " bytes");
+            }
+        }
+    }
+}
+
+void FileViewer::draw(Canvas& c) {
+    const auto& area = theme::kContent;
+    refresh();
+    c.setTextDatum(top_left);
+    theme::Rect body{area.x, area.y + 10, area.w, kRows * theme::kLineHeight};
+    std::string right, keys = "Tab: hex";
+    bool scanning = scan_ && !scan_->done;
+
+    switch (mode_) {
+        case Mode::Text:
+        case Mode::Hex: {
+            c.setFont(&fonts::body);
+            c.setTextColor(size_ == 0 ? theme::kMuted : theme::kText);
+            if (size_ == 0) c.drawString("(empty)", 4, body.y + 1);
+            for (size_t i = 0; i < shown_.size(); i++) c.drawString(shown_[i].c_str(), 4, body.y + 1 + static_cast<int>(i) * theme::kLineHeight);
+            uint32_t at = mode_ == Mode::Text && pager_ ? pager_->top() : hexTop_ * 8;
+            if (size_ > 0) {  // where in the file the screen is
+                int barH = 12, barY = body.y + static_cast<int>(static_cast<uint64_t>(body.h - barH) * at / size_);
+                c.fillRect(area.w - 2, barY, 2, barH, theme::kMuted);
+            }
+            right = formatBytes(size_);
+            keys = std::string("Tab: ") + (mode_ != base_ ? "back" : mode_ == Mode::Text ? "hex" : "text") + "  t: top  b: end";
+            break;
+        }
+        case Mode::Gpx: {
+            std::vector<std::string> lines;
+            if (scanning) lines.push_back("Reading the Track... " + std::to_string(scan_->percent.load()) + "%");
+            else if (scan_ && !scan_->error.empty()) lines.push_back(scan_->error);
+            else if (scan_) lines = scan_->gpx.lines();
+            widgets::textLines(c, lines, 0, body);
+            right = formatBytes(size_);
+            keys = "Tab: the file as text";
+            break;
+        }
+        case Mode::Pcap: {
+            c.setFont(&fonts::body);
+            c.setTextColor(theme::kMuted);
+            if (scanning) c.drawString("Reading the Capture...", 4, body.y + 1);
+            else if (scan_ && !scan_->error.empty()) c.drawString(scan_->error.c_str(), 4, body.y + 1);
+            else if (scan_ && scan_->packets.empty()) c.drawString("No packets in this Capture.", 4, body.y + 1);
+            else if (scan_) {
+                int from = rowsFrom_;
+                widgets::list(c, packets_, body, [&](int i) {
+                    size_t row = static_cast<size_t>(i - from);
+                    return row < shown_.size() ? shown_[row] : std::string();
+                });
+                right = std::to_string(scan_->packets.size()) + (scan_->morePackets ? "+ packets" : " packets");
+                keys = "Enter: the packet  Tab: hex";
+            }
+            break;
+        }
+        case Mode::Packet: widgets::textLines(c, details_, detailsTop_, {area.x + 2, area.y + 2, area.w - 2, area.h - 2}); return;
+        case Mode::Ota: {
+            std::vector<std::string> lines;
+            bool ok = scan_ && scan_->done && scan_->genuine;
+            if (scanning) {
+                lines.push_back("Checking it as an install would:");
+                lines.push_back("signature and contents, " + std::to_string(scan_->percent.load()) + "%");
+            } else if (scan_) {
+                if (!scan_->version.empty()) lines.push_back("Version " + scan_->version);
+                lines.push_back(std::string("Running ") + versionString());
+                if (ok) {
+                    lines.push_back("Signed with the project's key, intact.");
+                    if (scan_->older) lines.push_back("Older than what's running.");
+                } else {
+                    lines.push_back("Not installable:");
+                    lines.push_back(scan_->error.empty() ? "it ends too early" : scan_->error);
+                }
+            }
+            widgets::textLines(c, lines, 0, body);
+            right = formatBytes(size_);
+            keys = ok ? "Enter: install  Tab: hex" : "Tab: hex";
+            if (confirm_) {
+                widgets::dialog(c, "Install update?", "The device restarts into " + scan_->version + " once it's written.", *confirm_);
+                return;
+            }
+            break;
+        }
+    }
+
+    c.setFont(&fonts::small);
+    c.setTextColor(theme::kMuted);
+    c.setTextDatum(top_left);
+    c.drawString(title().c_str(), 4, area.y + 1);
+    c.setTextDatum(top_right);
+    c.drawString(right.c_str(), area.w - 3, area.y + 1);
+    c.setTextDatum(top_left);
+    c.drawString(keys.c_str(), 4, area.y + area.h - 9);
+}
+
+}  // namespace roro
diff --git a/src/apps/file_viewer.h b/src/apps/file_viewer.h
new file mode 100644
index 0000000..1b17823
--- /dev/null
+++ b/src/apps/file_viewer.h
@@ -0,0 +1,67 @@
+#pragma once
+
+#include <FS.h>
+
+#include <memory>
+#include <string>
+#include <vector>
+
+#include "dialog_model.h"
+#include "key_event.h"
+#include "list_model.h"
+#include "services/storage_service.h"
+#include "services/update_service.h"
+#include "text_pager.h"
+#include "ui/canvas.h"
+#include "ui/theme.h"
+
+namespace roro {
+
+// Looks inside a file for the Storage App (F1, Q134), by type: text read as it's scrolled, a hex
+// dump, a Capture's packets, a Track's summary, an Update File's version and whether it's
+// genuine. Tab switches to the text or the hex of the same file. Nothing here changes a file.
+class FileViewer {
+   public:
+    FileViewer(StorageService& storage, UpdateService& update) : storage_(storage), update_(update) {}
+
+    void open(const std::string& path, uint32_t size);
+    void close();
+    bool onKey(const KeyEvent& e);  // false: leave the viewer
+    bool update(uint32_t nowMs);    // true: draw again
+    void draw(Canvas& c);
+
+   private:
+    enum class Mode { Text, Hex, Gpx, Pcap, Packet, Ota };
+    static constexpr int kRows = 8;
+    static constexpr int kCols = 38;
+    struct Scan;  // what a storage job reads through a whole file for: shared with that job
+
+    size_t readAt(uint32_t offset, uint8_t* into, size_t len);
+    void show(Mode mode);
+    void startScan(Mode mode);
+    void refresh();  // reads what the screen shows, when it has moved
+    void openPacket(int index);
+    void scroll(int lines);
+    std::string title() const;
+
+    StorageService& storage_;
+    UpdateService& update_;
+    std::string path_;
+    uint32_t size_ = 0;
+    Mode mode_ = Mode::Text, base_ = Mode::Text;
+    std::shared_ptr<fs::File> file_;  // opened and read on the storage task only
+    std::unique_ptr<files::TextPager> pager_;
+    uint32_t hexTop_ = 0;  // in rows of eight bytes
+    std::vector<std::string> shown_;  // the rows on screen
+    bool stale_ = true;
+    std::shared_ptr<Scan> scan_;
+    bool scanShown_ = false;
+    int shownPercent_ = -1;
+    ListModel packets_{kRows};
+    int rowsFrom_ = -1;
+    std::vector<std::string> details_;
+    int detailsTop_ = 0;
+    std::unique_ptr<DialogModel> confirm_;
+};
+
+}  // namespace roro
diff --git a/src/apps/storage_page.cpp b/src/apps/maintenance_page.cpp
similarity index 95%
rename from src/apps/storage_page.cpp
rename to src/apps/maintenance_page.cpp
index bd87d8f..da1dbc7 100644
--- a/src/apps/storage_page.cpp
+++ b/src/apps/maintenance_page.cpp
@@ -1,4 +1,4 @@
-#include "storage_page.h"
+#include "maintenance_page.h"
 
 #include "ui/widgets.h"
 
@@ -9,25 +9,25 @@ constexpr int kAges = sizeof(kCleanupAgeLabels) / sizeof(kCleanupAgeLabels[0]);
 constexpr int kCategories = sizeof(kCleanupCategories) / sizeof(kCleanupCategories[0]);
 }  // namespace
 
-void StoragePage::enter() {
+void MaintenancePage::enter() {
     view_ = View::Main;
     dialog_.reset();
     main_.setCount(kRows);
     main_.select(kCleanUp);
 }
 
-void StoragePage::warn(const char* text) {
+void MaintenancePage::warn(const char* text) {
     bus_.publish(Event::withText(EventType::Notification, text, static_cast<int32_t>(NotificationLevel::Warning)));
 }
 
-uint64_t StoragePage::categoryBytes(int category) const {
+uint64_t MaintenancePage::categoryBytes(int category) const {
     uint64_t sum = 0;
     if (category < static_cast<int>(listing_.size()))
         for (auto& f : listing_[category]) sum += f.bytes;
     return sum;
 }
 
-CleanupPlan StoragePage::planFor(int age) const {
+CleanupPlan MaintenancePage::planFor(int age) const {
     int today = clock_.today();
     auto cutoff = static_cast<CleanupAge>(age);
     // Without a clock only "Everything" can be judged.
@@ -35,7 +35,7 @@ CleanupPlan StoragePage::planFor(int age) const {
     return CleanupPlan::make(listing_[categories_.selected()], cutoff, today);
 }
 
-bool StoragePage::onKey(const KeyEvent& e) {
+bool MaintenancePage::onKey(const KeyEvent& e) {
     if (dialog_) {
         dialog_->onKey(e);
         int result = dialog_->result();
@@ -109,7 +109,7 @@ bool StoragePage::onKey(const KeyEvent& e) {
     return true;
 }
 
-void StoragePage::draw(Canvas& c) {
+void MaintenancePage::draw(Canvas& c) {
     const auto& area = theme::kContent;
     if (!haveListing_ && storage_.listingReady()) {
         listing_ = storage_.listing();
diff --git a/src/apps/storage_page.h b/src/apps/maintenance_page.h
similarity index 84%
rename from src/apps/storage_page.h
rename to src/apps/maintenance_page.h
index 8de205c..fe8de7f 100644
--- a/src/apps/storage_page.h
+++ b/src/apps/maintenance_page.h
@@ -15,10 +15,10 @@
 
 namespace roro {
 
-// Settings → Storage: card usage, Storage Clean-up (category → age → confirm) and erasing the card.
-class StoragePage {
+// Storage → Maintenance: card usage, Storage Clean-up (category → age → confirm) and erasing the card.
+class MaintenancePage {
    public:
-    StoragePage(StorageService& storage, ClockService& clock, EventBus& bus)
+    MaintenancePage(StorageService& storage, ClockService& clock, EventBus& bus)
         : storage_(storage), clock_(clock), bus_(bus) {}
 
     void enter();
diff --git a/src/apps/settings_app.cpp b/src/apps/settings_app.cpp
index b599409..d0ecc77 100644
--- a/src/apps/settings_app.cpp
+++ b/src/apps/settings_app.cpp
@@ -27,9 +27,6 @@ bool SettingsApp::onKey(const KeyEvent& e) {
         case Page::Menu: return onMenuKey(e);
         case Page::Text: return onTextKey(e);
         case Page::Choice: return onChoiceKey(e);
-        case Page::Storage:
-            if (!storagePage_.onKey(e)) page_ = Page::Menu;
-            return true;
         case Page::About: return onAboutKey(e);
         case Page::Wifi:
             if (!wifiPage_.onKey(e)) page_ = Page::Menu;
@@ -70,10 +67,6 @@ bool SettingsApp::onMenuKey(const KeyEvent& e) {
         case Kind::Slider: break;
         case Kind::Page:
             switch (menu_.row(i)) {
-                case Row::Storage:
-                    page_ = Page::Storage;
-                    storagePage_.enter();
-                    break;
                 case Row::Wifi:
                     page_ = Page::Wifi;
                     wifiPage_.enter();
@@ -130,8 +123,8 @@ bool SettingsApp::onAboutKey(const KeyEvent& e) {
 }
 
 void SettingsApp::update(uint32_t nowMs) {
-    // Live values on Storage and About.
-    bool live = page_ == Page::Storage || page_ == Page::About || page_ == Page::Firmware ||
+    // Live values on About and Firmware.
+    bool live = page_ == Page::About || page_ == Page::Firmware ||
                 (page_ == Page::Wifi && wifiPage_.live());
     if (live && nowMs - lastRefreshMs_ >= 500) {
         lastRefreshMs_ = nowMs;
@@ -188,7 +181,6 @@ void SettingsApp::draw(Canvas& c) {
             widgets::list(c, choices_, area, [&](int i) { return (i == current ? "* " : "  ") + options[i]; });
             break;
         }
-        case Page::Storage: storagePage_.draw(c); break;
         case Page::About: widgets::textLines(c, aboutLines(), 0, area); break;
         case Page::Wifi: wifiPage_.draw(c); break;
         case Page::Firmware: firmwarePage_.draw(c); break;
diff --git a/src/apps/settings_app.h b/src/apps/settings_app.h
index 42d6af8..7c9dcb1 100644
--- a/src/apps/settings_app.h
+++ b/src/apps/settings_app.h
@@ -14,7 +14,6 @@
 #include "services/clock_service.h"
 #include "services/storage_service.h"
 #include "apps/firmware_page.h"
-#include "apps/storage_page.h"
 #include "apps/wifi_settings_page.h"
 #include "settings_menu.h"
 #include "ui/theme.h"
@@ -33,14 +32,13 @@ struct SettingsAppDeps {
     UpdateService& update;
 };
 
-// Settings: every user-facing setting, plus the Storage and About pages.
+// Settings: every user-facing setting, plus the Wi-Fi, Firmware and About pages.
 class SettingsApp : public App {
    public:
     explicit SettingsApp(const SettingsAppDeps& deps)
         : d_(deps),
           menu_(deps.settings),
           wifiPage_(deps.settings, deps.savedNetworks, deps.wifi, deps.bus),
-          storagePage_(deps.storage, deps.clock, deps.bus),
           firmwarePage_(deps.update, deps.wifi, deps.storage) {}
     void onEnter() override;
     bool onKey(const KeyEvent& e) override;
@@ -51,7 +49,7 @@ class SettingsApp : public App {
     void draw(Canvas& c) override;
 
    private:
-    enum class Page { Menu, Text, Choice, Storage, About, Wifi, Firmware };
+    enum class Page { Menu, Text, Choice, About, Wifi, Firmware };
 
     bool onMenuKey(const KeyEvent& e);
     bool onTextKey(const KeyEvent& e);
@@ -63,7 +61,6 @@ class SettingsApp : public App {
     SettingsAppDeps d_;
     SettingsMenu menu_;
     WifiSettingsPage wifiPage_;
-    StoragePage storagePage_;
     FirmwarePage firmwarePage_;
     Page page_ = Page::Menu;
     ListModel list_{theme::kContent.h / theme::kLineHeight};
diff --git a/src/apps/storage_app.cpp b/src/apps/storage_app.cpp
new file mode 100644
index 0000000..f97462a
--- /dev/null
+++ b/src/apps/storage_app.cpp
@@ -0,0 +1,566 @@
+#include "storage_app.h"
+
+#include <Arduino.h>
+
+#include <algorithm>
+#include <cstdio>
+
+#include "cleanup_plan.h"
+#include "file_names.h"
+#include "ui/canvas.h"
+#include "ui/fonts.h"
+#include "ui/widgets.h"
+
+namespace roro {
+
+using files::baseName;
+using files::joinPath;
+using files::parentOf;
+
+namespace {
+constexpr uint32_t kMessageMs = 4000;
+constexpr uint32_t kQuietMs = 300;  // an operation shorter than this shows no progress
+
+const char* kindText(const std::string& name) {
+    switch (files::kindOf(name)) {
+        case files::FileKind::Text: return "Text";
+        case files::FileKind::Gpx: return "Track (GPX)";
+        case files::FileKind::Pcap: return "Capture (pcap)";
+        case files::FileKind::Ota: return "Update File";
+        default: return "File";
+    }
+}
+
+std::string plural(uint32_t n, const char* one) { return std::to_string(n) + " " + one + (n == 1 ? "" : "s"); }
+}  // namespace
+
+void StorageApp::onEnter() {
+    view_ = ESP.getFreeHeap() < kStartFloor ? View::NoMemory : View::Browse;
+    ask_ = Ask::None;
+    dialog_.reset();
+    message_.clear();
+    cardPresent_ = storage_.state().present;
+    // A copy left running is picked up where it is; anything else starts from a fresh listing.
+    if (wait_ != Wait::Work && view_ == View::Browse) open(cwd_);
+    else want_ = cwd_;
+    requestRedraw();
+}
+
+void StorageApp::onExit() {
+    if (wait_ != Wait::None && wait_ != Wait::Work) {
+        ops_.cancel();
+        wait_ = Wait::None;
+    }
+    viewer_.close();
+    wantList_ = false;
+    loaded_ = false;
+    list_ = files::FileList();  // its memory only while the App is open
+    rows_.setCount(0);
+    std::vector<std::string>().swap(details_);
+}
+
+void StorageApp::say(const std::string& text) {
+    message_ = text;
+    messageMs_ = millis();
+    requestRedraw();
+}
+
+// What's on screen stays, with its path, until the new listing is in: cwd_ changes then.
+void StorageApp::open(const std::string& folder, const std::string& select) {
+    want_ = folder;
+    selectAfter_ = select;
+    wantList_ = true;  // started from update(), once the card is free
+    waitSinceMs_ = millis();
+}
+
+StorageApp::Item StorageApp::selected() const {
+    int i = rows_.selected();
+    if (!loaded_ || i < 0 || i >= static_cast<int>(list_.count())) return {};
+    Item item;
+    item.path = joinPath(cwd_, list_.name(i));
+    item.folder = list_.folder(i);
+    return item;
+}
+
+bool StorageApp::work(const std::string& why, const std::string& selectAfter) {
+    if (!why.empty()) {
+        say(why);
+        return false;
+    }
+    wait_ = Wait::Work;
+    waitSinceMs_ = millis();
+    selectAfter_ = selectAfter;
+    return true;
+}
+
+void StorageApp::update(uint32_t nowMs) {
+    bool present = storage_.state().present;
+    if (present != cardPresent_) {  // taken out, put in, or erased: back to the top
+        cardPresent_ = present;
+        cwd_ = want_ = "/";
+        selectAfter_.clear();
+        loaded_ = false;
+        list_.clear();
+        rows_.setCount(0);
+        wantList_ = present;
+        clip_ = Item();
+        if (view_ == View::Viewer) viewer_.close();
+        if (view_ == View::Details || view_ == View::Name || view_ == View::Viewer) view_ = View::Browse;
+        requestRedraw();
+    }
+    if (wantList_ && present && wait_ == Wait::None && !ops_.busy() && ops_.list(want_).empty()) {
+        wantList_ = false;
+        wait_ = Wait::List;
+        waitSinceMs_ = nowMs;
+    }
+    if (view_ == View::Viewer && viewer_.update(nowMs)) requestRedraw();
+    FileOps::Status s;
+    if (wait_ != Wait::None && ops_.finished(s)) {
+        onFinished(s);
+        requestRedraw();
+    }
+    // millis(), not nowMs: a message set by a key in this same pass is newer than the pass's own time.
+    uint32_t now = millis();
+    if ((wait_ != Wait::None || wantList_) && now - lastDrawMs_ >= 250) requestRedraw();
+    if (!message_.empty() && now - messageMs_ >= kMessageMs) {
+        message_.clear();
+        requestRedraw();
+    }
+    if (view_ == View::Maintenance && now - lastDrawMs_ >= 1000) requestRedraw();
+}
+
+void StorageApp::onFinished(const FileOps::Status& s) {
+    Wait was = wait_;
+    wait_ = Wait::None;
+    switch (was) {
+        case Wait::List: {
+            if (!s.error.empty()) {
+                say(s.error);
+                selectAfter_.clear();
+                // A folder that can't be opened leaves the screen as it is; if it's the one on
+                // screen that went away, back to the top.
+                if (want_ != cwd_ && loaded_) {
+                    want_ = cwd_;
+                    return;
+                }
+                if (want_ != "/") return open("/");
+                list_.clear();
+            } else {
+                ops_.takeListing(list_);
+                list_.sort(sort_);
+            }
+            cwd_ = want_;
+            loaded_ = true;
+            int count = static_cast<int>(list_.count()) + (cwd_ == "/" ? 1 : 0);
+            int at = selectAfter_.empty() ? -1 : list_.find(selectAfter_);
+            rows_.setCount(count);
+            rows_.select(at >= 0 ? at : selectIndex_);
+            selectAfter_.clear();
+            selectIndex_ = 0;
+            break;
+        }
+        case Wait::CountToDelete:
+            if (!s.error.empty()) say(s.error);
+            else if (!s.cancelled) askDelete(target_, s.files, s.bytes);
+            break;
+        case Wait::CountForDetails:
+            if (view_ != View::Details || details_.empty() || s.cancelled) break;
+            details_.back() = s.error.empty() ? plural(s.files, "file") + ", " + formatBytes(s.bytes) : s.error;
+            break;
+        case Wait::Work: {
+            std::string name = files::fitName(baseName(target_.path), 20);
+            if (s.exists && pasting_) {
+                question_ = name + " exists already in this folder. Replace it?";
+                ask_ = Ask::Replace;
+                dialog_.reset(new DialogModel({"Cancel", "Replace"}));
+                return;
+            }
+            if (!s.error.empty()) say(s.error);
+            else if (s.cancelled) say(s.op == FileOps::Op::Copy ? "Cancelled: nothing was copied" : "Cancelled after " + plural(s.files, "file"));
+            else {
+                switch (s.op) {
+                    case FileOps::Op::Copy: say(s.files == 1 ? "Copied " + name : "Copied " + plural(s.files, "file") + " to " + name); break;
+                    case FileOps::Op::Move: say((pasting_ ? "Moved " : "Renamed to ") + name); break;
+                    case FileOps::Op::Delete: say(s.files == 1 ? "Deleted " + name : "Deleted " + name + ", " + plural(s.files, "file")); break;
+                    default: say("Made " + name); break;
+                }
+                // The clipboard must not point at what has moved or gone.
+                bool gone = s.op == FileOps::Op::Delete || s.op == FileOps::Op::Move;
+                if (clip_ && gone && files::isInside(clip_.path, s.path)) clip_ = Item();
+            }
+            open(cwd_, selectAfter_);
+            break;
+        }
+        default: break;
+    }
+}
+
+void StorageApp::paste(bool replace) {
+    if (!clip_) return say("Nothing to paste: c copies, x cuts");
+    std::string name = baseName(clip_.path), why;
+    if (cut_) {
+        why = ops_.move(clip_.path, clip_.folder, joinPath(cwd_, name), replace);
+    } else {
+        // A copy next to its original: "a (2).txt", or the next number that's free.
+        if (parentOf(clip_.path) == cwd_)
+            for (int n = 2; n < 100 && list_.find(name) >= 0; n++) name = files::copyName(baseName(clip_.path), n);
+        why = ops_.copy(clip_.path, clip_.folder, cwd_, name, replace);
+    }
+    target_.path = joinPath(cwd_, name);
+    target_.folder = clip_.folder;
+    pasting_ = true;
+    selectIndex_ = rows_.selected();  // where to stay if nothing comes of it
+    work(why, name);
+}
+
+void StorageApp::askDelete(const Item& item, uint32_t count, uint32_t bytes) {
+    std::string name = files::fitName(baseName(item.path), 22);
+    if (!item.folder) question_ = "Delete " + name + " (" + formatBytes(bytes) + ")?";
+    else if (count == 0) question_ = "Delete the empty folder " + name + "?";
+    else question_ = "Delete " + name + " and its " + plural(count, "file") + " (" + formatBytes(bytes) + ")?";
+    question_ += " It can't be undone.";
+    target_ = item;
+    ask_ = Ask::Delete;
+    dialog_.reset(new DialogModel({"Cancel", "Delete"}));
+    requestRedraw();
+}
+
+void StorageApp::onAnswer(int button) {
+    Ask asked = ask_;
+    ask_ = Ask::None;
+    dialog_.reset();
+    if (button != 1) return;
+    switch (asked) {
+        case Ask::Delete:
+            selectIndex_ = rows_.selected();
+            pasting_ = false;
+            work(ops_.remove(target_.path, target_.folder), "");
+            break;
+        case Ask::Replace: paste(true); break;
+        case Ask::Maintenance:
+            view_ = View::Maintenance;
+            maintenance_.enter();
+            break;
+        default: break;
+    }
+}
+
+void StorageApp::showDetails(const Item& item) {
+    int i = rows_.selected();
+    std::string name = baseName(item.path);
+    details_.clear();
+    details_.push_back(name);
+    if (item.folder) details_.push_back("Folder");
+    else {
+        uint32_t size = list_.size(i);
+        std::string text = std::string(kindText(name)) + ", " + formatBytes(size);
+        if (size >= 1024) text += " (" + std::to_string(size) + " bytes)";
+        details_.push_back(text);
+    }
+    details_.push_back("Modified " + files::formatStamp(list_.modified(i)));
+    details_.push_back("In " + cwd_);
+    std::string why = ops_.whyReadOnly(item.path, item.folder);
+    if (!why.empty()) details_.push_back("Read-only: " + why);
+    if (item.folder) {
+        details_.push_back("Counting...");
+        if (ops_.count(item.path).empty()) wait_ = Wait::CountForDetails;
+        else details_.pop_back();
+    }
+    detailsTop_ = 0;
+    view_ = View::Details;
+}
+
+bool StorageApp::onKey(const KeyEvent& e) {
+    requestRedraw();
+    if (view_ == View::NoMemory) return false;
+    if (view_ == View::Maintenance) {
+        if (!maintenance_.onKey(e)) {
+            view_ = View::Browse;
+            open(cwd_);  // a Clean-up may have emptied what was shown
+        }
+        return true;
+    }
+    if (view_ == View::Viewer) {
+        if (!viewer_.onKey(e)) {
+            viewer_.close();
+            view_ = View::Browse;
+        }
+        return true;
+    }
+    if (dialog_) {
+        dialog_->onKey(e);
+        if (dialog_->result() != DialogModel::kPending) onAnswer(dialog_->result());
+        return true;
+    }
+    if (view_ == View::Details) {
+        if (e.key == Key::Up) detailsTop_ = std::max(0, detailsTop_ - 1);
+        else if (e.key == Key::Down) detailsTop_++;  // clamped when drawn
+        else if (e.key == Key::Back || e.key == Key::Select) {
+            if (wait_ == Wait::CountForDetails) ops_.cancel();
+            view_ = View::Browse;
+        }
+        return true;
+    }
+    // A copy, a delete or a count is running: Back stops it, nothing else gets through. The same
+    // while a folder is being read, which nothing stops.
+    if (wantList_) return true;
+    if (wait_ != Wait::None) {
+        if (e.key == Key::Back && wait_ != Wait::List) ops_.cancel();
+        return true;
+    }
+    if (view_ == View::Name) return onNameKey(e);
+    return onBrowseKey(e);
+}
+
+bool StorageApp::onNameKey(const KeyEvent& e) {
+    switch (e.key) {
+        case Key::Char: editor_.insert(e.ch); break;
+        case Key::Delete: editor_.backspace(); break;
+        case Key::Left: editor_.left(); break;
+        case Key::Right: editor_.right(); break;
+        case Key::Back: view_ = View::Browse; break;
+        case Key::Select: {
+            const std::string& name = editor_.text();
+            std::string why = files::checkName(name);
+            if (!why.empty()) {
+                say(why);
+                break;
+            }
+            pasting_ = false;
+            bool started = true;
+            if (!renaming_) {
+                target_.path = joinPath(cwd_, name);
+                target_.folder = true;
+                started = work(ops_.makeFolder(target_.path), name);
+            } else if (name != baseName(target_.path)) {
+                std::string to = joinPath(cwd_, name);
+                started = work(ops_.move(target_.path, target_.folder, to), name);
+                if (started) target_.path = to;
+            }
+            if (started) view_ = View::Browse;
+            break;
+        }
+        default: break;
+    }
+    return true;
+}
+
+bool StorageApp::onBrowseKey(const KeyEvent& e) {
+    auto askMaintenance = [this]() {
+        question_ = "Clean-up and Erase delete files for good: there is no undo.";
+        ask_ = Ask::Maintenance;
+        dialog_.reset(new DialogModel({"Back", "Go on"}));
+    };
+    if (e.key == Key::Back) {
+        if (cwd_ == "/" || !cardPresent_) return false;  // leaves the App
+        open(parentOf(cwd_), baseName(cwd_));
+        return true;
+    }
+    uint32_t ch = e.key == Key::Char ? (e.ch >= 'A' && e.ch <= 'Z' ? e.ch + 32 : e.ch) : 0;
+    if (ch == 'm') askMaintenance();
+    if (!cardPresent_ || !loaded_) return true;
+
+    Item item = selected();
+    switch (e.key) {
+        case Key::Up: rows_.up(); return true;
+        case Key::Down: rows_.down(); return true;
+        case Key::Left: rows_.pageUp(); return true;
+        case Key::Right: rows_.pageDown(); return true;
+        case Key::Select:
+            if (onMaintenanceRow()) askMaintenance();
+            else if (item && item.folder) open(item.path);
+            else if (item) {
+                viewer_.open(item.path, list_.size(rows_.selected()));
+                view_ = View::Viewer;
+            }
+            return true;
+        case Key::Delete: ch = 'd'; break;
+        default: break;
+    }
+    switch (ch) {
+        case 'v': paste(false); return true;
+        case 'n':
+            renaming_ = false;
+            editor_.setText("");
+            view_ = View::Name;
+            return true;
+        case 's': {
+            sort_ = sort_ == files::FileSort::Name ? files::FileSort::Date : sort_ == files::FileSort::Date ? files::FileSort::Size : files::FileSort::Name;
+            std::string keep = item ? baseName(item.path) : "";
+            bool onLast = onMaintenanceRow();
+            list_.sort(sort_);
+            if (!onLast) rows_.select(std::max(0, list_.find(keep)));
+            say(sort_ == files::FileSort::Name ? "Sorted by name" : sort_ == files::FileSort::Date ? "Sorted by date, newest first" : "Sorted by size, biggest first");
+            return true;
+        }
+        default: break;
+    }
+    if (!item || !(ch == 'c' || ch == 'x' || ch == 'r' || ch == 'd' || ch == 'i')) return true;
+
+    std::string name = files::fitName(baseName(item.path), 18);
+    if (ch == 'i') {
+        showDetails(item);
+        return true;
+    }
+    if (ch == 'c') {
+        clip_ = item;
+        cut_ = false;
+        say("v pastes a copy of " + name);
+        return true;
+    }
+    // Cut, rename and delete change the original: the rules of Q130 first.
+    std::string why = ops_.whyReadOnly(item.path, item.folder);
+    if (!why.empty()) {
+        say(why);
+        return true;
+    }
+    if (ch == 'x') {
+        clip_ = item;
+        cut_ = true;
+        say("v moves " + name + " here");
+    } else if (ch == 'r') {
+        target_ = item;
+        renaming_ = true;
+        editor_.setText(baseName(item.path));
+        view_ = View::Name;
+    } else if (item.folder) {  // 'd': what's inside is counted first (Q132)
+        target_ = item;
+        std::string busy = ops_.count(item.path);
+        if (!busy.empty()) say(busy);
+        else {
+            wait_ = Wait::CountToDelete;
+            waitSinceMs_ = millis();
+        }
+    } else {
+        askDelete(item, 1, list_.size(rows_.selected()));
+    }
+    return true;
+}
+
+void StorageApp::draw(Canvas& c) {
+    lastDrawMs_ = millis();
+    const auto& area = theme::kContent;
+    c.setTextDatum(top_left);
+    switch (view_) {
+        case View::NoMemory:
+            c.setFont(&fonts::bold);
+            c.setTextColor(theme::kWarning);
+            c.drawString("Not enough memory", 4, area.y + 4);
+            c.setFont(&fonts::body);
+            c.setTextColor(theme::kMuted);
+            c.drawString("Close what's running (IRC, a page", 4, area.y + 22);
+            c.drawString("in Gemini) and open Storage again.", 4, area.y + 22 + theme::kLineHeight);
+            return;
+        case View::Maintenance: maintenance_.draw(c); return;
+        case View::Viewer: viewer_.draw(c); return;
+        case View::Details: {
+            std::vector<std::string> lines;
+            auto measure = widgets::bodyMeasure(c);
+            for (auto& d : details_)
+                for (auto& l : wrapText(d, area.w - 12, measure)) lines.push_back(l);
+            int rows = (area.h - 2) / theme::kLineHeight;
+            detailsTop_ = std::clamp(detailsTop_, 0, std::max(0, static_cast<int>(lines.size()) - rows));
+            widgets::textLines(c, lines, detailsTop_, {area.x + 2, area.y + 2, area.w - 2, area.h - 2});
+            return;
+        }
+        default: break;
+    }
+    drawBrowse(c);
+    if (view_ == View::Name) {
+        theme::Rect box{16, 44, theme::kWidth - 32, 48};
+        c.fillRect(box.x, box.y, box.w, box.h, theme::kBackground);
+        c.drawRect(box.x, box.y, box.w, box.h, theme::kAccent);
+        c.setFont(&fonts::bold);
+        c.setTextColor(theme::kText);
+        c.drawString(renaming_ ? "Rename" : "New folder", box.x + 6, box.y + 4);
+        widgets::lineEditor(c, editor_, {box.x + 6, box.y + 22, box.w - 12, theme::kLineHeight + 4});
+    }
+    if (dialog_) {
+        const char* title = ask_ == Ask::Delete ? "Delete" : ask_ == Ask::Replace ? "Replace" : "Maintenance";
+        widgets::dialog(c, title, question_, *dialog_);
+    } else if ((wait_ == Wait::Work || wait_ == Wait::CountToDelete) && millis() - waitSinceMs_ >= kQuietMs) {
+        drawProgress(c);
+    }
+}
+
+void StorageApp::drawBrowse(Canvas& c) {
+    const auto& area = theme::kContent;
+    StorageState card = storage_.state();
+
+    // Where we are, and how much room is left (Q129).
+    c.setFont(&fonts::small);
+    c.setTextColor(theme::kMuted);
+    std::string right;
+    if (card.present) {
+        right = formatBytes(card.totalBytes - card.usedBytes) + " free";
+        if (loaded_ && list_.more() > 0) right = "first " + std::to_string(list_.count()) + " of " + std::to_string(list_.count() + list_.more());
+    }
+    size_t room = static_cast<size_t>((area.w - 12) / 5) - right.size() - 1;
+    std::string path = cwd_.size() <= room ? cwd_ : ".." + cwd_.substr(cwd_.size() - (room - 2));
+    c.drawString(path.c_str(), 4, area.y + 1);
+    c.setTextDatum(top_right);
+    c.drawString(right.c_str(), area.w - 3, area.y + 1);
+    c.setTextDatum(top_left);
+
+    theme::Rect rows{area.x, area.y + 10, area.w, kRows * theme::kLineHeight};
+    c.setFont(&fonts::body);
+    if (!card.present) {
+        c.setTextColor(theme::kWarning);
+        c.drawString("No SD card", 4, rows.y + 4);
+    } else if (!loaded_) {
+        // Nothing yet: the footer says what's being read.
+    } else if (rows_.count() == 0) {
+        c.setTextColor(theme::kMuted);
+        c.drawString("Nothing in this folder.", 4, rows.y + 4);
+        c.drawString("n makes a folder, v pastes.", 4, rows.y + 4 + theme::kLineHeight);
+    } else {
+        int entries = static_cast<int>(list_.count());
+        auto value = [&](int i) {
+            return i >= entries ? std::string(">") : files::rowDetail(list_.folder(i), list_.size(i), list_.modified(i));
+        };
+        widgets::list(
+            c, rows_, rows,
+            [&](int i) {
+                if (i >= entries) return std::string("Maintenance");
+                size_t fits = static_cast<size_t>((area.w - 22) / 6) - value(i).size();
+                return files::fitName(list_.name(i), fits);
+            },
+            value);
+    }
+
+    // Footer: a message for a few seconds, what v would paste, or the keys.
+    c.setFont(&fonts::small);
+    bool showMessage = !message_.empty() && millis() - messageMs_ < kMessageMs;
+    c.setTextColor(showMessage ? theme::kWarning : theme::kMuted);
+    std::string keys = "c x v:paste r:name d:del n:new i:info s:sort";
+    if ((wantList_ || wait_ == Wait::List) && millis() - waitSinceMs_ >= kQuietMs) keys = "Reading " + files::fitName(want_, 30) + "...";
+    else if (clip_) keys = std::string("v: ") + (cut_ ? "move " : "copy ") + files::fitName(baseName(clip_.path), 20) + " here";
+    c.drawString(showMessage ? message_.c_str() : keys.c_str(), 4, area.y + area.h - 9);
+}
+
+void StorageApp::drawProgress(Canvas& c) {
+    FileOps::Status s = ops_.status();
+    theme::Rect box{20, 40, theme::kWidth - 40, 58};
+    c.fillRect(box.x, box.y, box.w, box.h, theme::kBackground);
+    c.drawRect(box.x, box.y, box.w, box.h, theme::kAccent);
+    c.setTextDatum(top_left);
+    c.setFont(&fonts::bold);
+    c.setTextColor(theme::kText);
+    const char* verb = s.op == FileOps::Op::Copy ? "Copying " : s.op == FileOps::Op::Delete ? "Deleting " : s.op == FileOps::Op::Count ? "Counting " : "Moving ";
+    c.drawString((verb + files::fitName(baseName(target_.path), 20)).c_str(), box.x + 6, box.y + 4);
+
+    c.setFont(&fonts::body);
+    c.setTextColor(theme::kMuted);
+    std::string line = plural(s.files, "file");
+    if (s.op == FileOps::Op::Copy && s.totalBytes > 0) {
+        int w = box.w - 12, done = static_cast<int>(static_cast<uint64_t>(s.doneBytes) * w / s.totalBytes);
+        c.drawRect(box.x + 6, box.y + 21, w, 7, theme::kMuted);
+        c.fillRect(box.x + 6, box.y + 21, std::min(done, w), 7, theme::kAccent);
+        line = formatBytes(s.doneBytes) + " of " + formatBytes(s.totalBytes);
+    }
+    c.drawString(line.c_str(), box.x + 6, box.y + 31);
+    c.setFont(&fonts::small);
+    c.drawString("Back: cancel", box.x + 6, box.y + box.h - 10);
+}
+
+}  // namespace roro
diff --git a/src/apps/storage_app.h b/src/apps/storage_app.h
new file mode 100644
index 0000000..fa2229e
--- /dev/null
+++ b/src/apps/storage_app.h
@@ -0,0 +1,96 @@
+#pragma once
+
+#include <memory>
+#include <string>
+#include <vector>
+
+#include "app.h"
+#include "apps/file_viewer.h"
+#include "apps/maintenance_page.h"
+#include "dialog_model.h"
+#include "event_bus.h"
+#include "file_list.h"
+#include "line_editor.h"
+#include "list_model.h"
+#include "services/clock_service.h"
+#include "services/file_ops.h"
+#include "services/storage_service.h"
+#include "ui/theme.h"
+
+namespace roro {
+
+// The Storage App (docs/milestones/F1.md): the SD card's folders and files, one item at a time
+// with a clipboard (Q131). Enter opens a folder, or a file in its viewer (Q134); Back goes up;
+// c copy, x cut, v paste here, r rename, d delete, n new folder, i details, s sort. At the top of the card, the last row is Maintenance:
+// usage, Storage Clean-up and erasing the card, behind a warning (Q128).
+class StorageApp : public App {
+   public:
+    StorageApp(FileOps& ops, StorageService& storage, ClockService& clock, UpdateService& update, EventBus& bus)
+        : ops_(ops), storage_(storage), bus_(bus), maintenance_(storage, clock, bus), viewer_(storage, update) {}
+    void onEnter() override;
+    void onExit() override;
+    bool onKey(const KeyEvent& e) override;
+    bool textEntryActive() const override { return view_ == View::Name; }
+    void update(uint32_t nowMs) override;
+    void draw(Canvas& c) override;
+
+   private:
+    enum class View { Browse, Details, Name, Viewer, Maintenance, NoMemory };
+    enum class Ask { None, Delete, Replace, Maintenance };
+    enum class Wait { None, List, CountToDelete, CountForDetails, Work };  // what the running operation is for
+    static constexpr int kRows = 8;
+    static constexpr size_t kStartFloor = 55 * 1024;  // Q86, Q136
+
+    struct Item {
+        std::string path;
+        bool folder = false;
+        explicit operator bool() const { return !path.empty(); }
+    };
+
+    void open(const std::string& folder, const std::string& select = "");
+    void onFinished(const FileOps::Status& s);
+    bool onBrowseKey(const KeyEvent& e);
+    bool onNameKey(const KeyEvent& e);
+    void onAnswer(int button);
+    Item selected() const;  // empty on the Maintenance row or in an empty folder
+    bool onMaintenanceRow() const { return cwd_ == "/" && rows_.selected() == static_cast<int>(list_.count()); }
+    void paste(bool replace);
+    void askDelete(const Item& item, uint32_t files, uint32_t bytes);
+    void showDetails(const Item& item);
+    bool work(const std::string& why, const std::string& selectAfter);  // an operation was asked for: did it start?
+    void say(const std::string& text);
+    void drawBrowse(Canvas& c);
+    void drawProgress(Canvas& c);
+
+    FileOps& ops_;
+    StorageService& storage_;
+    EventBus& bus_;
+    MaintenancePage maintenance_;
+    FileViewer viewer_;
+
+    View view_ = View::Browse;
+    std::string cwd_ = "/", want_ = "/";  // the folder on screen; the one being read
+    files::FileList list_;
+    files::FileSort sort_ = files::FileSort::Name;
+    ListModel rows_{kRows};
+    bool wantList_ = false, loaded_ = false, cardPresent_ = false;
+    std::string selectAfter_;  // after the next listing: the name to select, or else the row
+    int selectIndex_ = 0;
+
+    Wait wait_ = Wait::None;
+    uint32_t waitSinceMs_ = 0, lastDrawMs_ = 0;
+    Item clip_, target_;  // the clipboard; what a dialog, the editor or the details are about
+    bool cut_ = false;
+    Ask ask_ = Ask::None;
+    std::unique_ptr<DialogModel> dialog_;
+    std::string question_;
+    LineEditor editor_{60};
+    bool renaming_ = false;  // Name view: renaming target_, or else a new folder
+    bool pasting_ = false;   // the operation running came from v: it may ask to replace
+    std::vector<std::string> details_;
+    int detailsTop_ = 0;
+    std::string message_;
+    uint32_t messageMs_ = 0;
+};
+
+}  // namespace roro
diff --git a/src/main.cpp b/src/main.cpp
index e40b49b..d5f0598 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -14,6 +14,7 @@
 #include "apps/launcher_app.h"
 #include "apps/lora_scanner_app.h"
 #include "apps/settings_app.h"
+#include "apps/storage_app.h"
 #include "apps/system_app.h"
 #include "apps/wifi_tools_app.h"
 #include "apps/setup_app.h"
@@ -30,10 +31,12 @@
 #include "sd_fault.h"
 #include "service_manager.h"
 #include "platform/identity.h"
+#include "file_names.h"
 #include "services/battery_service.h"
 #include "services/irc_service.h"
 #include "services/clock_service.h"
 #include "services/debug_console.h"
+#include "services/file_ops.h"
 #include "services/gemini_service.h"
 #include "services/gnss_service.h"
 #include "services/power_service.h"
@@ -62,6 +65,8 @@ static Screen screen;
 // Constructed in setup(), after the hardware and Settings are ready.
 static BatteryService* battery;
 static StorageService* storageService;
+static FileOps* fileOps;
+static std::vector<std::string> filesInUse(const std::string& path, bool folder);
 static PowerService* power;
 static ClockService* clockService;
 static GnssService* gnssService;
@@ -175,6 +180,7 @@ void setup() {
     savedNetworks->load();
     wifi = new WifiService(settings, *savedNetworks, *clockService);
     update = new UpdateService(nvs, *wifi, *savedNetworks, *storageService, bus, settings);
+    fileOps = new FileOps(*storageService, filesInUse);
     irc = new IrcService(nvs, "roro_" + identity::defaultShortName(), *wifi, *storageService, *clockService, bus);
     notifier = new Notifier(bus, settings);
     notifier->onShow = [](uint32_t now, uint32_t until) { power->onNotification(now, until); };
@@ -204,6 +210,7 @@ void setup() {
     apps->registerApp({"gnss", "GNSS", false, new GnssApp(*gnssService, settings)});
     apps->registerApp({"gemini", "Gemini", false, new GeminiApp(*geminiService)});
     apps->registerApp({"lora", "LoRa Scanner", false, new LoraScannerApp(*radioService, *loraCapture, settings, *clockService)});
+    apps->registerApp({"storage", "Storage", false, new StorageApp(*fileOps, *storageService, *clockService, *update, bus)});
     apps->registerApp({"system", "System", false,
                        new SystemApp(*wifi, *battery, *storageService, *radioService, *gnssService, nvs)});
     apps->registerApp({"settings", "Settings", false,
@@ -397,6 +404,69 @@ static std::vector<TaskSample> tasksBefore;
 static uint32_t tasksTotal = 0, tasksDueMs = 0;
 static bool tasksPending = false;
 
+// What the firmware is writing right now: the Storage App and the console leave those alone (Q130).
+static std::vector<std::string> filesInUse(const std::string& path, bool folder) {
+    std::vector<std::string> open;
+    if (gnssService->tracking()) open.push_back(gnssService->trackPath());
+    if (loraCapture->capturing()) open.push_back(loraCapture->path());
+    if (upload.active()) open.push_back(upload.partPath());
+    if (irc->running() && path != "/irc" && files::isInside(path, "/irc")) {
+        // Today's Logs, and any folder that may hold one: the IRC Service appends whenever a line comes.
+        std::string date = clockService->localDate();
+        std::string today = (date.empty() ? "undated" : date) + ".log";
+        if (folder) open.push_back(files::joinPath(path, today));
+        else if (files::baseName(path) == today) open.push_back(path);
+    }
+    return open;
+}
+
+// `cp`, `mv`, `rm`, `mkdir`, `du` run as the Storage App's operations do; the result prints here.
+static bool consoleFileOp = false;
+
+static void fileOpsStep() {
+    FileOps::Status s;
+    if (!consoleFileOp || !fileOps->finished(s)) return;
+    consoleFileOp = false;
+    static const char* const kNames[] = {"", "ls", "du", "cp", "mv", "rm", "mkdir"};
+    const char* name = kNames[static_cast<int>(s.op)];
+    if (!s.error.empty()) console.printf("%s: error %s\n", name, s.error.c_str());
+    else if (s.cancelled) console.printf("%s: cancelled\n", name);
+    else if (s.op == FileOps::Op::Count) console.printf("du: %s, %u files, %u bytes\n", s.path.c_str(), (unsigned)s.files, (unsigned)s.bytes);
+    else if (s.op == FileOps::Op::Copy) console.printf("cp: ok %u files, %u bytes in %.1f s\n", (unsigned)s.files, (unsigned)s.doneBytes, s.ms / 1000.0);
+    else if (s.op == FileOps::Op::Delete) console.printf("rm: ok %u files in %.1f s\n", (unsigned)s.files, s.ms / 1000.0);
+    else console.printf("%s: ok\n", name);
+}
+
+static void fileCommand(const String& line) {
+    int space = line.indexOf(' ');
+    std::string command = line.substring(0, space).c_str(), rest = line.substring(space + 1).c_str();
+    bool force = rest.rfind("-f ", 0) == 0;  // replace what's there
+    if (force) rest = rest.substr(3);
+    size_t split = rest.find('\t');  // two paths: a tab between them if either has a space
+    if (split == std::string::npos) split = rest.find(' ');
+    std::string a = rest.substr(0, split), b = split == std::string::npos ? "" : rest.substr(split + 1);
+    std::string why;
+    bool exists = false, folder = false;
+    if (command == "cancel") return fileOps->cancel();
+    if (!storageService->state().present) why = "no SD card";
+    else if (command == "du") why = fileOps->count(rest);
+    else if (command == "mkdir") why = fileOps->makeFolder(rest);
+    else if (command == "rm") {
+        folder = fileOps->isFolder(rest, exists);
+        why = exists ? fileOps->remove(rest, folder) : "It isn't there";
+    } else if (b.empty()) why = "two paths, please";
+    else {
+        folder = fileOps->isFolder(a, exists);
+        bool intoExists = false;
+        bool into = fileOps->isFolder(b, intoExists);  // `cp a /folder` keeps the name
+        if (!exists) why = "It isn't there";
+        else if (command == "cp") why = into ? fileOps->copy(a, folder, b, files::baseName(a), force) : fileOps->copy(a, folder, files::parentOf(b), files::baseName(b), force);
+        else why = fileOps->move(a, folder, into ? files::joinPath(b, files::baseName(a)) : b, force);
+    }
+    if (!why.empty()) return (void)console.printf("%s: error %s\n", command.c_str(), why.c_str());
+    consoleFileOp = true;
+}
+
 static uint32_t loopPasses = 0;  // counted in loop(), for `tasks` (issue #40)
 #ifdef RORO_DEBUG
 static bool loopSpin = false;  // `loop spin on`: no rest between passes, to compare load and radio noise
@@ -417,6 +487,7 @@ static const char* const kHelp =
     "reboot            restart\n"
     "boot other        restart into the other app slot (manual Rollback)\n"
     "log level <0-5>   ESP-IDF log level (0 none ... 5 verbose)\n"
+    "ls [folder] | du <path> | mkdir <path> | rm <path> | cp [-f] <from> <to> | mv [-f] <from> <to> | cancel   the SD card, with the Storage App's rules\n"
     "lora probe | lora status | lora rx on|off | lora preset <name>   the LoRa radio, receive only\n"
     "lora capture start|stop   a LoRa Capture to /captures/lora (pcap, LoRaTap)\n"
     "lora sweep on [from MHz] [to MHz] [step kHz] | off | dump   RSSI across a band (863 870 100)\n"
@@ -431,7 +502,7 @@ static const char* const kHelp =
     "wifi dns <a> [b] | wifi dns always on|off | wifi ntp <a> [b]   DNS and NTP servers\n"
     "gemini get <url>  fetch a Gemini page and report header, size, certificate, heap\n"
     "irc start | irc stop | irc dump | irc say <buffer> <text>\n"
-    "ls [folder] | rm <path> | install <path.ota> (Update from SD)\n"
+    "install <path.ota>   Update from SD\n"
     "sd card | sd list | cat <path> | log <text> | burst | sound on|off | short | normal\n"
 #ifdef RORO_DEBUG
     "crash abort|wdt   crash on purpose (to test crash reports and Safe Mode)\n"
@@ -439,6 +510,7 @@ static const char* const kHelp =
     "loop spin on|off  make the main loop spin without resting, to compare load and radio noise\n"
     "lora noise test [gnss|quiet] | lora noise report   Sweep under one changed condition at a time (Wi-Fi goes off for a moment)\n"
     "lora inject <hex> [rssi] [snr]   a packet into the LoRa Scanner as if received (nothing is sent)\n"
+    "sd fill <folder> <count>   makes that many small files there, to test a crowded folder\n"
     "coredump get      (Debug Console only) send the raw core dump: use scripts/rdbg.py coredump\n"
     "reset             (Debug Console only) restart at once, even if the main loop is stuck\n"
     "get <path> | put <path> <size> <sha256> | screenshot   (Debug Console only) binary, see rdbg.py\n"
@@ -495,20 +567,42 @@ static void runCommand(String line) {
         esp_log_level_set("*", static_cast<esp_log_level_t>(constrain(level, 0, 5)));
         console.printf("log level: %d\n", constrain(level, 0, 5));
     }
-    if (line == "ls" || line.startsWith("ls ") || line.startsWith("rm ")) {
+    if (line.startsWith("cp ") || line.startsWith("mv ") || line.startsWith("rm ") || line.startsWith("mkdir ") ||
+        line.startsWith("du ") || line == "cancel")
+        fileCommand(line);
+    if (line == "ls" || line.startsWith("ls ")) {
         if (!storageService->state().present) return (void)console.println("sd: no card");
-        bool list = !line.startsWith("rm ");
         std::string path = line.length() > 3 ? line.substring(3).c_str() : "/";
-        storageService->runJob([list, path]() {  // card access stays on the storage task
-            if (!list) return (void)console.printf("rm: %s %s\n", path.c_str(), SD.remove(path.c_str()) ? "removed" : "failed");
+        storageService->runJob([path]() {  // card access stays on the storage task
             File dir = SD.open(path.c_str());
             if (!dir || !dir.isDirectory()) return (void)console.printf("ls: %s is not a folder\n", path.c_str());
             for (File f = dir.openNextFile(); f; f = dir.openNextFile())
-                console.printf("%10u  %s%s\n", f.isDirectory() ? 0u : (unsigned)f.size(), f.name(), f.isDirectory() ? "/" : "");
+                console.printf("%10u  %-16s  %s%s\n", f.isDirectory() ? 0u : (unsigned)f.size(),
+                               files::formatStamp(static_cast<uint32_t>(f.getLastWrite())).c_str(), f.name(), f.isDirectory() ? "/" : "");
             console.printf("ls: end of %s\n", path.c_str());
         });
     }
     if (line.startsWith("install ")) update->installFromSd(line.substring(8).c_str());  // Update from SD
+#ifdef RORO_DEBUG
+    if (line.startsWith("sd fill ")) {  // sd fill <folder> <count>: small files, to test a crowded folder
+        int space = line.lastIndexOf(' ');
+        std::string folder = line.substring(8, space).c_str();
+        int count = constrain(line.substring(space + 1).toInt(), 0, 1000);
+        storageService->runJob([folder, count]() {
+            int made = 0;
+            for (int i = 1; i <= count; i++) {
+                char name[24];
+                snprintf(name, sizeof name, "file-%04d.txt", i);
+                File f = SD.open(files::joinPath(folder, name).c_str(), FILE_WRITE);
+                if (!f) break;
+                f.printf("file %d\n", i);
+                f.close();
+                made++;
+            }
+            console.printf("sd fill: %d files in %s\n", made, folder.c_str());
+        });
+    }
+#endif
     if (line == "lora probe" && radioService) radioService->probe(console);
     if (line == "lora status" && radioService) radioService->printStatus(console);
     if ((line == "lora rx on" || line == "lora rx off") && radioService) radioService->setEcho(line.endsWith("on"));
@@ -912,6 +1006,7 @@ static void loopPass() {
     if (noiseTest) noiseTest->step(now);
 #endif
     noteStableOnce(now);
+    fileOpsStep();
     uploadStep();
     printListingWhenReady();
     M5Cardputer.update();
diff --git a/src/services/clock_service.h b/src/services/clock_service.h
index c613f43..cec23eb 100644
--- a/src/services/clock_service.h
+++ b/src/services/clock_service.h
@@ -1,6 +1,7 @@
 #pragma once
 
 #include <Arduino.h>
+#include <sys/time.h>
 
 #include "clock_model.h"
 #include "event_bus.h"
@@ -20,7 +21,16 @@ class ClockService : public Service {
     const char* name() const override { return "clock"; }
     void start() override { applyTimezone(); }
 
-    bool set(int64_t utcSeconds, TimeSource source) { return model_.set(utcSeconds, source, millis()); }
+    bool set(int64_t utcSeconds, TimeSource source) {
+        if (!model_.set(utcSeconds, source, millis())) return false;
+        // The system's own clock too (F1, Q137): the card's files are dated from it, and NTP was
+        // the only thing setting it. NTP has just done so itself.
+        if (source != TimeSource::Ntp) {
+            timeval now = {static_cast<time_t>(utcSeconds), 0};
+            settimeofday(&now, nullptr);
+        }
+        return true;
+    }
     const ClockModel& model() const { return model_; }
 
     // UTC seconds, or -1 if the clock isn't set.
diff --git a/src/services/file_ops.cpp b/src/services/file_ops.cpp
new file mode 100644
index 0000000..b30cbd7
--- /dev/null
+++ b/src/services/file_ops.cpp
@@ -0,0 +1,492 @@
+#include "services/file_ops.h"
+
+#include <Arduino.h>
+#include <SD.h>
+
+#include <ctime>
+#include <memory>
+
+#include "file_names.h"
+
+namespace roro {
+
+using files::baseName;
+using files::joinPath;
+using files::parentOf;
+
+namespace {
+// The FatFs drive the card is mounted as: SDFS keeps it to itself.
+struct SdDrive : fs::SDFS {
+    static uint8_t of(fs::SDFS& sd) { return sd.*(&SdDrive::_pdrv); }
+};
+
+// A FAT date and time (local, as the firmware wrote them) as Unix time; 0 if there's none.
+uint32_t fatTime(uint16_t date, uint16_t time) {
+    if (date == 0) return 0;
+    struct tm t = {};
+    t.tm_year = (date >> 9) + 80;
+    t.tm_mon = ((date >> 5) & 15) - 1;
+    t.tm_mday = date & 31;
+    t.tm_hour = time >> 11;
+    t.tm_min = (time >> 5) & 63;
+    t.tm_sec = (time & 31) * 2;
+    t.tm_isdst = -1;
+    time_t at = mktime(&t);
+    return at < 0 ? 0 : static_cast<uint32_t>(at);
+}
+
+struct Guard {
+    explicit Guard(SemaphoreHandle_t l) : l_(l) { xSemaphoreTake(l_, portMAX_DELAY); }
+    ~Guard() { xSemaphoreGive(l_); }
+    SemaphoreHandle_t l_;
+};
+}  // namespace
+
+FileOps::FileOps(StorageService& storage, InUse inUse)
+    : storage_(storage), inUse_(std::move(inUse)), lock_(xSemaphoreCreateMutex()) {}
+
+FileOps::Status FileOps::status() const {
+    Guard g(lock_);
+    Status s = status_;
+    s.running = busy_;
+    s.doneBytes = doneBytes_;
+    s.files = files_;
+    return s;
+}
+
+bool FileOps::finished(Status& out) {
+    // The storage task drops its jobs when the card goes: nothing would ever end this one.
+    if (busy_ && !storage_.state().present) {
+        fail("The card went away");
+        busy_ = false;
+        done_ = true;
+    }
+    if (!done_.exchange(false)) return false;
+    out = status();
+    out.running = false;
+    return true;
+}
+
+void FileOps::takeListing(files::FileList& out) {
+    Guard g(lock_);
+    out = std::move(listing_);
+    listing_.clear();
+}
+
+bool FileOps::isFolder(const std::string& path, bool& exists) {
+    bool folder = false;
+    exists = false;
+    storage_.runAndWait([&]() {
+        fs::File f = SD.open(path.c_str());
+        exists = static_cast<bool>(f);
+        folder = f && f.isDirectory();
+    });
+    return folder;
+}
+
+std::string FileOps::whyReadOnly(const std::string& path, bool folder) const {
+    return files::whyReadOnly(path, inUse_(path, folder));
+}
+
+std::string FileOps::start(Op op, const std::string& path) {
+    if (busy_) return "The card is busy with something else";
+    if (!storage_.state().present) return "No SD card";
+    {
+        Guard g(lock_);
+        status_ = Status();
+        status_.op = op;
+        status_.path = path;
+    }
+    closeAll();  // only handles a vanished card left behind
+    listOpen_ = false;
+    op_ = op;
+    phase_ = 0;
+    undo_ = false;
+    cancel_ = false;
+    done_ = false;
+    doneBytes_ = 0;
+    files_ = 0;
+    countBytes_ = 0;
+    startMs_ = millis();
+    busy_ = true;
+    queue();
+    return "";
+}
+
+void FileOps::queue() {
+    storage_.runJob([this]() { slice(); });
+}
+
+std::string FileOps::list(const std::string& folder) {
+    from_ = folder;
+    return start(Op::List, folder);
+}
+
+std::string FileOps::count(const std::string& path) {
+    from_ = path;
+    return start(Op::Count, path);
+}
+
+std::string FileOps::copy(const std::string& from, bool folder, const std::string& intoFolder, const std::string& name, bool replace) {
+    if (busy_) return "The card is busy with something else";
+    std::string why = files::whyNotInto(from, intoFolder);
+    // A copy next to its original is fine: only the name must differ.
+    if (why == "It's already there" && name != baseName(from)) why.clear();
+    if (why.empty()) why = files::checkName(name);
+    if (!why.empty()) return why;
+    from_ = from;
+    to_ = joinPath(intoFolder, name);
+    replace_ = replace;
+    sourceIsFolder_ = folder;
+    return start(Op::Copy, from);
+}
+
+std::string FileOps::move(const std::string& from, bool folder, const std::string& to, bool replace) {
+    if (busy_) return "The card is busy with something else";
+    std::string why = files::whyReadOnly(from, inUse_(from, folder));
+    if (why.empty() && from == to) why = "It's already there";
+    if (why.empty() && parentOf(to) != parentOf(from)) why = files::whyNotInto(from, parentOf(to));
+    if (why.empty()) why = files::checkName(baseName(to));
+    if (!why.empty()) return why;
+    from_ = from;
+    to_ = to;
+    replace_ = replace;
+    sourceIsFolder_ = folder;
+    return start(Op::Move, from);
+}
+
+std::string FileOps::remove(const std::string& path, bool folder) {
+    if (busy_) return "The card is busy with something else";
+    std::string why = files::whyReadOnly(path, inUse_(path, folder));
+    if (!why.empty()) return why;
+    from_ = path;
+    sourceIsFolder_ = folder;
+    return start(Op::Delete, path);
+}
+
+std::string FileOps::makeFolder(const std::string& path) {
+    if (busy_) return "The card is busy with something else";
+    std::string why = files::checkName(baseName(path));
+    if (why.empty() && files::isInside(path, files::kGeminiCache)) why = std::string(files::kGeminiCache) + " is the Gemini App's working space";
+    if (!why.empty()) return why;
+    from_ = path;
+    return start(Op::MakeFolder, path);
+}
+
+void FileOps::fail(const std::string& why) {
+    Guard g(lock_);
+    if (status_.error.empty()) status_.error = why;
+}
+
+void FileOps::closeAll() {
+    if (in_) in_.close();
+    if (out_) out_.close();
+    for (auto& d : dirs_)
+        if (d) d.close();
+    dirs_.clear();
+    paths_.clear();
+}
+
+void FileOps::finish() {
+    if (listOpen_) f_closedir(&listDir_);
+    listOpen_ = false;
+    closeAll();
+    {
+        Guard g(lock_);
+        status_.cancelled = cancel_ && status_.error.empty() && (op_ == Op::Copy || op_ == Op::Delete || op_ == Op::Count);
+        status_.bytes = countBytes_;
+        status_.ms = millis() - startMs_;
+    }
+    op_ = Op::None;
+    busy_ = false;
+    done_ = true;
+}
+
+bool FileOps::enter(const std::string& path) {
+    fs::File d = SD.open(path.c_str());
+    if (!d || !d.isDirectory()) return false;
+    dirs_.push_back(d);
+    paths_.push_back(path);
+    return true;
+}
+
+// One slice on the storage task, then back in the queue behind whatever else is waiting.
+void FileOps::slice() {
+    if (!busy_) return;  // given up on: the card went away (finished())
+    bool over = true;
+    switch (op_) {
+        case Op::List: over = sliceList(); break;
+        case Op::Count: over = sliceCount(); break;
+        case Op::Copy: over = sliceCopy(); break;
+        case Op::Delete: over = sliceDelete(); break;
+        case Op::Move: {
+            if (!SD.exists(from_.c_str())) fail("It isn't there any more");
+            else if (SD.exists(to_.c_str()) && !replace_) {
+                Guard g(lock_);
+                status_.exists = true;
+                status_.error = baseName(to_) + " exists already";
+            } else {
+                if (SD.exists(to_.c_str())) SD.remove(to_.c_str());  // a file: a folder in the way makes the rename fail
+                if (!SD.rename(from_.c_str(), to_.c_str())) fail("The card refused to move it");
+                else files_ = 1;
+            }
+            break;
+        }
+        case Op::MakeFolder:
+            if (SD.exists(from_.c_str())) fail(baseName(from_) + " exists already");
+            else if (!SD.mkdir(from_.c_str())) fail("The card refused to make the folder");
+            break;
+        default: break;
+    }
+    if (over) finish();
+    else queue();
+}
+
+// Straight from FatFs, one pass over the folder: the Arduino File looks every entry up by name
+// again for its size and its date, which made 300 entries take over two seconds.
+bool FileOps::sliceList() {
+    uint32_t t0 = millis();
+    if (phase_ == 0) {
+        Guard g(lock_);
+        listing_.clear();
+        std::string path = std::string(1, static_cast<char>('0' + SdDrive::of(SD))) + ":" + from_;
+        if (f_opendir(&listDir_, path.c_str()) != FR_OK) {
+            status_.error = from_ + " isn't a folder";
+            return true;
+        }
+        listOpen_ = true;
+        phase_ = 1;
+    }
+    while (millis() - t0 < kSliceMs) {
+        if (cancel_) return true;
+        FILINFO info;
+        if (f_readdir(&listDir_, &info) != FR_OK || info.fname[0] == 0) return true;
+        bool folder = info.fattrib & AM_DIR;
+        Guard g(lock_);
+        listing_.add(info.fname, folder ? 0 : static_cast<uint32_t>(info.fsize), fatTime(info.fdate, info.ftime), folder);
+    }
+    return false;
+}
+
+// What's inside, for "Delete saved and its 42 files?" (Q132) and for a copy's total.
+bool FileOps::sliceCount() {
+    uint32_t t0 = millis();
+    if (phase_ == 0) {
+        phase_ = 1;
+        fs::File f = SD.open(from_.c_str());
+        if (!f) {
+            fail("It isn't there any more");
+            return true;
+        }
+        if (!f.isDirectory()) {
+            files_ = 1;
+            countBytes_ = static_cast<uint32_t>(f.size());
+            return true;
+        }
+        f.close();
+        enter(from_);
+    }
+    while (!dirs_.empty() && millis() - t0 < kSliceMs) {
+        if (cancel_) return true;
+        fs::File f = dirs_.back().openNextFile();
+        if (!f) {
+            dirs_.back().close();
+            dirs_.pop_back();
+            paths_.pop_back();
+        } else if (f.isDirectory()) {
+            std::string sub = joinPath(paths_.back(), f.name());
+            f.close();
+            enter(sub);
+        } else {
+            files_++;
+            countBytes_ += static_cast<uint32_t>(f.size());
+        }
+    }
+    return dirs_.empty();
+}
+
+// Deletes files as the walk meets them and each folder once it's empty. Also how a cancelled or
+// failed copy takes back what it had written (undo_).
+bool FileOps::sliceDelete() {
+    uint32_t t0 = millis();
+    if (phase_ == 0) {
+        phase_ = 1;
+        fs::File f = SD.open(from_.c_str());
+        if (!f) {
+            if (!undo_) fail("It isn't there any more");
+            return true;
+        }
+        bool folder = f.isDirectory();
+        f.close();
+        if (!folder) {
+            if (!SD.remove(from_.c_str())) fail("The card refused to delete it");
+            else if (!undo_) files_ = 1;
+            return true;
+        }
+        enter(from_);
+    }
+    while (!dirs_.empty() && millis() - t0 < kSliceMs) {
+        if (cancel_ && !undo_) return true;  // what's deleted stays deleted
+        fs::File f = dirs_.back().openNextFile();
+        if (!f) {
+            std::string done = paths_.back();
+            dirs_.back().close();
+            dirs_.pop_back();
+            paths_.pop_back();
+            if (!SD.rmdir(done.c_str())) {
+                fail("The card refused to delete " + baseName(done));
+                return true;
+            }
+        } else if (f.isDirectory()) {
+            std::string sub = joinPath(paths_.back(), f.name());
+            f.close();
+            if (!enter(sub)) {
+                fail("The card refused to open " + baseName(sub));
+                return true;
+            }
+        } else {
+            std::string path = joinPath(paths_.back(), f.name());
+            f.close();
+            if (!SD.remove(path.c_str())) {
+                fail("The card refused to delete " + baseName(path));
+                return true;
+            }
+            if (!undo_) files_++;
+        }
+    }
+    return dirs_.empty();
+}
+
+// Phases 0 and 1 count the source (the walk of Count), 2 checks and prepares, 3 copies, 4 takes
+// a failed or cancelled copy back.
+bool FileOps::sliceCopy() {
+    uint32_t t0 = millis();
+    if (phase_ <= 1) {
+        if (!sliceCount()) return false;
+        phase_ = 2;
+    }
+    if (phase_ == 2) {
+        {
+            Guard g(lock_);
+            if (!status_.error.empty()) return true;
+            status_.totalBytes = countBytes_;
+        }
+        if (cancel_) return true;
+        files_ = 0;
+        StorageState card = storage_.state();
+        if (card.totalBytes - card.usedBytes < static_cast<uint64_t>(countBytes_) + 64 * 1024) {
+            fail("Not enough room on the card");
+            return true;
+        }
+        if (SD.exists(to_.c_str())) {
+            if (!replace_) {
+                Guard g(lock_);
+                status_.exists = true;
+                status_.error = baseName(to_) + " exists already";
+                return true;
+            }
+            if (sourceIsFolder_) {
+                fail("A folder with that name is in the way");
+                return true;
+            }
+            SD.remove(to_.c_str());
+        }
+        if (sourceIsFolder_) {
+            if (!SD.mkdir(to_.c_str()) || !enter(from_)) {
+                fail("The card refused to make the folder");
+                return true;
+            }
+        } else {
+            in_ = SD.open(from_.c_str(), FILE_READ);
+            outPath_ = to_;
+            out_ = SD.open(outPath_.c_str(), FILE_WRITE);
+            fileBytes_ = 0;
+            fileSize_ = in_ ? static_cast<uint32_t>(in_.size()) : 0;
+            if (!in_ || !out_) {
+                fail("The card refused to open the files");
+                phase_ = 4;
+                return false;
+            }
+        }
+        phase_ = 3;
+    }
+    if (phase_ == 3) {
+        std::unique_ptr<uint8_t[]> piece(new uint8_t[kPiece]);
+        while (millis() - t0 < kSliceMs) {
+            if (cancel_) {
+                phase_ = 4;
+                return false;
+            }
+            if (in_) {  // a file in progress
+                int n = in_.read(piece.get(), kPiece);
+                if (n > 0 && out_.write(piece.get(), n) != static_cast<size_t>(n)) n = -1;
+                if (n < 0) {
+                    fail("The card refused a write");
+                    phase_ = 4;
+                    return false;
+                }
+                if (n > 0) {
+                    doneBytes_ += n;
+                    fileBytes_ += n;
+                    continue;
+                }
+                in_.close();
+                out_.close();
+                // Q133: the sizes are compared. A Log that grew meanwhile is copied as far as it went.
+                fs::File check = SD.open(outPath_.c_str(), FILE_READ);
+                bool same = check && static_cast<uint32_t>(check.size()) == fileBytes_ && fileBytes_ >= fileSize_;
+                if (check) check.close();
+                if (!same) {
+                    fail("The copy of " + baseName(outPath_) + " isn't the size of the original");
+                    phase_ = 4;
+                    return false;
+                }
+                files_++;
+                continue;
+            }
+            if (dirs_.empty()) return true;  // a single file, or the whole folder: done
+            fs::File f = dirs_.back().openNextFile();
+            // The copy sits where the original does, relative to the two roots.
+            auto target = [&](const std::string& source) { return to_ + source.substr(from_.size()); };
+            if (!f) {
+                dirs_.back().close();
+                dirs_.pop_back();
+                paths_.pop_back();
+            } else if (f.isDirectory()) {
+                std::string sub = joinPath(paths_.back(), f.name());
+                f.close();
+                if (!SD.mkdir(target(sub).c_str()) || !enter(sub)) {
+                    fail("The card refused to make " + baseName(sub));
+                    phase_ = 4;
+                    return false;
+                }
+            } else {
+                std::string source = joinPath(paths_.back(), f.name());
+                f.close();
+                in_ = SD.open(source.c_str(), FILE_READ);
+                outPath_ = target(source);
+                out_ = SD.open(outPath_.c_str(), FILE_WRITE);
+                fileBytes_ = 0;
+                fileSize_ = in_ ? static_cast<uint32_t>(in_.size()) : 0;
+                if (!in_ || !out_) {
+                    fail("The card refused to open " + baseName(source));
+                    phase_ = 4;
+                    return false;
+                }
+            }
+        }
+        return false;
+    }
+    // Phase 4: take it back. The copy never replaced a folder, so everything under to_ is ours.
+    if (!undo_) {
+        closeAll();
+        undo_ = true;
+        from_ = to_;
+        phase_ = 0;
+        op_ = Op::Delete;  // finish() reports it as the copy it was: status_.op stays Copy
+        return false;
+    }
+    return true;
+}
+
+}  // namespace roro
diff --git a/src/services/file_ops.h b/src/services/file_ops.h
new file mode 100644
index 0000000..214390f
--- /dev/null
+++ b/src/services/file_ops.h
@@ -0,0 +1,102 @@
+#pragma once
+
+#include <FS.h>
+#include <ff.h>
+#include <freertos/FreeRTOS.h>
+#include <freertos/semphr.h>
+
+#include <atomic>
+#include <functional>
+#include <string>
+#include <vector>
+
+#include "file_list.h"
+#include "services/storage_service.h"
+
+namespace roro {
+
+// What the Storage App does to the card (docs/milestones/F1.md): list a folder, count what's in
+// one, copy, move, delete, make a folder. One operation at a time, on the storage task like every
+// card access, **in slices of about 150 ms**: a long copy re-queues itself between slices, so IRC
+// Logs, a Gemini page streaming to the card or a Capture are written in between and nobody waits
+// long enough to give up. The read-only rules of Q130 are checked here, whoever asks.
+class FileOps {
+   public:
+    enum class Op : uint8_t { None, List, Count, Copy, Move, Delete, MakeFolder };
+    // The files the firmware has open right now that matter for `path` (a folder or not).
+    using InUse = std::function<std::vector<std::string>(const std::string& path, bool folder)>;
+
+    struct Status {
+        Op op = Op::None;
+        bool running = false;
+        bool cancelled = false;
+        bool exists = false;   // a copy or move found something with that name: ask, then `replace`
+        std::string error;     // why it failed, for a human; empty when it worked
+        uint32_t doneBytes = 0, totalBytes = 0;  // a copy's progress
+        uint32_t files = 0;    // files copied or deleted so far; counted, for Count
+        uint32_t bytes = 0;    // Count: their total size
+        std::string path;      // what it was about
+        uint32_t ms = 0;       // how long it took, once it has ended
+    };
+
+    FileOps(StorageService& storage, InUse inUse);
+
+    // Each returns "" when the operation started, or why it can't. One at a time.
+    std::string list(const std::string& folder);
+    std::string count(const std::string& path);
+    std::string copy(const std::string& from, bool folder, const std::string& intoFolder, const std::string& name, bool replace = false);
+    std::string move(const std::string& from, bool folder, const std::string& to, bool replace = false);
+    std::string remove(const std::string& path, bool folder);
+    std::string makeFolder(const std::string& path);
+    void cancel() { cancel_ = true; }
+    // Why `path` can't be renamed, moved or deleted, or "": asked before the confirmation.
+    std::string whyReadOnly(const std::string& path, bool folder) const;
+
+    bool busy() const { return busy_; }
+    Status status() const;        // while it runs
+    bool finished(Status& out);   // true once, when it has ended
+    void takeListing(files::FileList& out);  // after a List finished without error
+
+    // For the console, which has no listing to know from: is `path` a folder? Waits for the card.
+    bool isFolder(const std::string& path, bool& exists);
+
+   private:
+    static constexpr uint32_t kSliceMs = 150;
+    static constexpr size_t kPiece = 4096;  // Q133
+
+    std::string start(Op op, const std::string& path);
+    void queue();
+    void slice();              // on the storage task
+    bool sliceList();          // each: true when the operation is over
+    bool sliceCount();
+    bool sliceCopy();
+    bool sliceDelete();
+    void fail(const std::string& why);
+    void finish();
+    bool enter(const std::string& path);  // push a folder onto the walk
+    void closeAll();
+
+    StorageService& storage_;
+    InUse inUse_;
+    mutable SemaphoreHandle_t lock_;  // status_, listing_
+    Status status_;
+    files::FileList listing_;
+    std::atomic<bool> busy_{false}, done_{false}, cancel_{false};
+    std::atomic<uint32_t> doneBytes_{0}, files_{0};
+
+    // The operation in hand: only the storage task touches these while it runs.
+    Op op_ = Op::None;
+    std::string from_, to_;
+    bool replace_ = false, sourceIsFolder_ = false, undo_ = false;
+    int phase_ = 0;
+    std::vector<fs::File> dirs_;       // the folders being walked, outermost first
+    std::vector<std::string> paths_;   // their paths
+    FF_DIR listDir_;                   // List reads the folder straight from FatFs
+    bool listOpen_ = false;
+    fs::File in_, out_;                // the file being copied
+    std::string outPath_;
+    uint32_t countBytes_ = 0, startMs_ = 0;
+    uint32_t fileBytes_ = 0, fileSize_ = 0;  // copied of the file in hand; its size when opened
+};
+
+}  // namespace roro
diff --git a/src/services/gnss_service.h b/src/services/gnss_service.h
index 7faee41..60fdaed 100644
--- a/src/services/gnss_service.h
+++ b/src/services/gnss_service.h
@@ -53,6 +53,7 @@ class GnssService : public Service {
     std::string startTrack(uint32_t nowMs);
     void stopTrack();
     bool tracking() const { return !trackPath_.empty(); }
+    const std::string& trackPath() const { return trackPath_; }
     int trackPoints() const { return trackPoints_; }
     uint32_t trackStartMs() const { return trackStartMs_; }
 
diff --git a/test/test_file_list/test_file_list.cpp b/test/test_file_list/test_file_list.cpp
index cb840ba..93024f5 100644
--- a/test/test_file_list/test_file_list.cpp
+++ b/test/test_file_list/test_file_list.cpp
@@ -100,6 +100,9 @@ void test_display() {
     TEST_ASSERT_EQUAL_STRING("0 B  -", rowDetail(false, 0, 315532800).c_str());  // 1980-01-01, FAT's zero
     TEST_ASSERT_EQUAL_STRING("2026-10-05 20:00", formatStamp(1791230400).c_str());
     TEST_ASSERT_EQUAL_STRING("-", formatStamp(0).c_str());
+    TEST_ASSERT_EQUAL_STRING("notes.txt", fitName("notes.txt", 19).c_str());
+    TEST_ASSERT_EQUAL_STRING("20261005-18..2.pcap", fitName("20261005-180932.pcap", 19).c_str());
+    TEST_ASSERT_EQUAL_INT(19, fitName("a-very-long-folder-name-without-end", 19).size());
 }
 
 int main() {
diff --git a/test/test_file_views/test_file_views.cpp b/test/test_file_views/test_file_views.cpp
new file mode 100644
index 0000000..4513609
--- /dev/null
+++ b/test/test_file_views/test_file_views.cpp
@@ -0,0 +1,133 @@
+#include <unity.h>
+
+#include <cstdlib>
+#include <ctime>
+#include <string>
+#include <vector>
+
+#include "file_views.h"
+#include "loratap.h"
+#include "track.h"
+
+using namespace roro;
+using namespace roro::files;
+
+void setUp() {}
+void tearDown() {}
+
+void test_hex_row() {
+    const uint8_t d[] = {'H', 'e', 'l', 'l', 'o', ',', ' ', 'w', 0x00, 0xFF, 'x'};
+    TEST_ASSERT_EQUAL_STRING("00010 4865 6c6c 6f2c 2077  Hello, w", hexRow(0x10, d, 8).c_str());
+    TEST_ASSERT_EQUAL_STRING("00018 00ff 78              ..x", hexRow(0x18, d + 8, 3).c_str());
+    TEST_ASSERT_TRUE(hexRow(0xFFFFF, d, 8).size() <= 38);
+}
+
+// A Track as the GNSS Service writes it, fed in pieces of every size: the same summary each time.
+void test_gpx_summary() {
+    setenv("TZ", "UTC", 1);
+    tzset();
+    std::string file = gnss::gpx::header("test");
+    int64_t t0 = 1791230400;  // 2026-10-05 20:00:00 UTC
+    for (int i = 0; i < 50; i++) file += gnss::gpx::point(48.0 + i * 0.0001, 7.0, i % 2 == 0, 200, t0 + i * 5) + "\n";
+    file += gnss::gpx::footer();
+    for (size_t piece : {size_t(1), size_t(7), size_t(64), size_t(1000), file.size()}) {
+        GpxSummary s;
+        for (size_t at = 0; at < file.size(); at += piece) s.feed(file.data() + at, std::min(piece, file.size() - at));
+        TEST_ASSERT_EQUAL_UINT32(50, s.points());
+        TEST_ASSERT_EQUAL_INT64(t0, s.start());
+        TEST_ASSERT_EQUAL_INT64(t0 + 245, s.end());
+        TEST_ASSERT_FLOAT_WITHIN(1.0f, 49 * 11.12f, static_cast<float>(s.meters()));  // 0.0001 degree of latitude: 11.12 m
+    }
+    GpxSummary s;
+    s.feed(file.data(), file.size());
+    auto lines = s.lines();
+    TEST_ASSERT_EQUAL_size_t(4, lines.size());
+    TEST_ASSERT_EQUAL_STRING("50 points", lines[0].c_str());
+    TEST_ASSERT_EQUAL_STRING("Started 2026-10-05 20:00", lines[1].c_str());
+    TEST_ASSERT_EQUAL_STRING("Lasted 4 min 05 s", lines[2].c_str());
+    TEST_ASSERT_EQUAL_STRING("Distance 545 m", lines[3].c_str());
+}
+
+void test_gpx_from_elsewhere_and_not_gpx() {
+    GpxSummary s;
+    std::string other = "<gpx><trk><trkseg><trkpt lon=\"7.0\" lat=\"48.0\"/><trkpt lat=\"48.01\" lon=\"7.0\">\n<ele>1</ele>\n</trkpt></trkseg></trk></gpx>";
+    s.feed(other.data(), other.size());
+    TEST_ASSERT_EQUAL_UINT32(2, s.points());
+    TEST_ASSERT_EQUAL_INT64(0, s.start());
+    TEST_ASSERT_FLOAT_WITHIN(5.0f, 1112.0f, static_cast<float>(s.meters()));
+    TEST_ASSERT_EQUAL_size_t(2, s.lines().size());  // no times: points and distance only
+    GpxSummary none;
+    std::string junk(10000, 'x');
+    none.feed(junk.data(), junk.size());
+    TEST_ASSERT_EQUAL_UINT32(0, none.points());
+}
+
+void test_durations() {
+    TEST_ASSERT_EQUAL_STRING("12 s", formatDuration(12).c_str());
+    TEST_ASSERT_EQUAL_STRING("4 min 10 s", formatDuration(250).c_str());
+    TEST_ASSERT_EQUAL_STRING("1 h 02 min", formatDuration(3725).c_str());
+}
+
+// What the LoRa Capture Service writes reads back the same.
+void test_pcap_round_trip() {
+    std::vector<uint8_t> file;
+    lora::appendPcapHeader(file);
+    lora::RxInfo rx;
+    rx.frequencyHz = 869525000;
+    rx.bandwidthKHz = 250;
+    rx.spreadingFactor = 11;
+    rx.rssi = -97;
+    rx.snr = -6.25f;
+    rx.noiseFloor = -106;
+    rx.syncWord = 0x2B;
+    const uint8_t payload[] = {1, 2, 3, 4, 5};
+    lora::appendRecord(file, 1791230400, 250000, rx, payload, sizeof payload);
+    lora::appendRecord(file, 1791230401, 0, rx, payload, 0);
+
+    PcapHeader h = parsePcapHeader(file.data(), file.size());
+    TEST_ASSERT_TRUE(h.ok);
+    TEST_ASSERT_EQUAL_UINT32(kLinkLoraTap, h.linkType);
+    size_t at = kPcapHeaderSize;
+    PcapRecord r;
+    TEST_ASSERT_TRUE(parsePcapRecord(file.data() + at, file.size() - at, r));
+    TEST_ASSERT_EQUAL_UINT32(1791230400, r.seconds);
+    TEST_ASSERT_EQUAL_UINT32(250000, r.micros);
+    TEST_ASSERT_EQUAL_UINT32(lora::kLoraTapSize + 5, r.length);
+    lora::RxInfo back;
+    TEST_ASSERT_TRUE(parseLoraTap(file.data() + at + kPcapRecordSize, r.length, back));
+    TEST_ASSERT_EQUAL_UINT32(869525000, back.frequencyHz);
+    TEST_ASSERT_EQUAL_FLOAT(250, back.bandwidthKHz);
+    TEST_ASSERT_EQUAL_UINT8(11, back.spreadingFactor);
+    TEST_ASSERT_EQUAL_FLOAT(-97, back.rssi);
+    TEST_ASSERT_EQUAL_FLOAT(-6.25f, back.snr);
+    TEST_ASSERT_EQUAL_FLOAT(-106, back.noiseFloor);
+    TEST_ASSERT_EQUAL_HEX8(0x2B, back.syncWord);
+    at += kPcapRecordSize + r.length;
+    TEST_ASSERT_TRUE(parsePcapRecord(file.data() + at, file.size() - at, r));
+    TEST_ASSERT_EQUAL_UINT32(lora::kLoraTapSize, r.length);
+    at += kPcapRecordSize + r.length;
+    TEST_ASSERT_EQUAL_size_t(file.size(), at);
+    TEST_ASSERT_FALSE(parsePcapRecord(file.data() + at, file.size() - at, r));  // the end
+}
+
+void test_not_a_pcap() {
+    const uint8_t junk[24] = {'n', 'o', 'p', 'e'};
+    TEST_ASSERT_FALSE(parsePcapHeader(junk, sizeof junk).ok);
+    TEST_ASSERT_FALSE(parsePcapHeader(junk, 10).ok);
+    const uint8_t huge[16] = {0, 0, 0, 0, 0, 0, 0, 0, 0xFF, 0xFF, 0xFF, 0x7F};
+    PcapRecord r;
+    TEST_ASSERT_FALSE(parsePcapRecord(huge, sizeof huge, r));
+    lora::RxInfo rx;
+    TEST_ASSERT_FALSE(parseLoraTap(junk, 10, rx));
+}
+
+int main() {
+    UNITY_BEGIN();
+    RUN_TEST(test_hex_row);
+    RUN_TEST(test_gpx_summary);
+    RUN_TEST(test_gpx_from_elsewhere_and_not_gpx);
+    RUN_TEST(test_durations);
+    RUN_TEST(test_pcap_round_trip);
+    RUN_TEST(test_not_a_pcap);
+    return UNITY_END();
+}
diff --git a/test/test_text_pager/test_text_pager.cpp b/test/test_text_pager/test_text_pager.cpp
new file mode 100644
index 0000000..604df73
--- /dev/null
+++ b/test/test_text_pager/test_text_pager.cpp
@@ -0,0 +1,156 @@
+#include <unity.h>
+
+#include <algorithm>
+#include <cstring>
+#include <string>
+
+#include "text_pager.h"
+
+using namespace roro::files;
+
+void setUp() {}
+void tearDown() {}
+
+static int reads = 0;
+static size_t biggestRead = 0;
+
+static TextPager pagerFor(const std::string& text, int cols, int rows) {
+    return TextPager(
+        [&text](uint32_t offset, uint8_t* into, size_t len) {
+            reads++;
+            biggestRead = std::max(biggestRead, len);
+            if (offset >= text.size()) return static_cast<size_t>(0);
+            size_t n = std::min(len, text.size() - offset);
+            std::memcpy(into, text.data() + offset, n);
+            return n;
+        },
+        static_cast<uint32_t>(text.size()), cols, rows);
+}
+
+void test_lines_and_wrapping() {
+    std::string text = "one\r\ntwo words that are too long\n\nlast";
+    TextPager p = pagerFor(text, 10, 8);
+    auto lines = p.lines();
+    TEST_ASSERT_EQUAL_size_t(6, lines.size());
+    TEST_ASSERT_EQUAL_STRING("one", lines[0].c_str());  // the \r is dropped
+    TEST_ASSERT_EQUAL_STRING("two words", lines[1].c_str());
+    TEST_ASSERT_EQUAL_STRING("that are", lines[2].c_str());
+    TEST_ASSERT_EQUAL_STRING("too long", lines[3].c_str());
+    TEST_ASSERT_EQUAL_STRING("", lines[4].c_str());
+    TEST_ASSERT_EQUAL_STRING("last", lines[5].c_str());
+    TEST_ASSERT_TRUE(p.atEnd());
+}
+
+void test_a_word_too_long_is_cut_and_a_space_at_the_edge_is_eaten() {
+    std::string text = "abcdefghijklmno\nabcde fghij klm";
+    TextPager p = pagerFor(text, 5, 8);
+    auto lines = p.lines();
+    TEST_ASSERT_EQUAL_STRING("abcde", lines[0].c_str());
+    TEST_ASSERT_EQUAL_STRING("fghij", lines[1].c_str());
+    TEST_ASSERT_EQUAL_STRING("klmno", lines[2].c_str());
+    TEST_ASSERT_EQUAL_STRING("abcde", lines[3].c_str());
+    TEST_ASSERT_EQUAL_STRING("fghij", lines[4].c_str());
+    TEST_ASSERT_EQUAL_STRING("klm", lines[5].c_str());
+}
+
+void test_accents_count_as_one_column_and_tabs_show_as_spaces() {
+    std::string text = "\xC3\xA9t\xC3\xA9 ici\n\ta\x01";
+    TextPager p = pagerFor(text, 3, 4);
+    auto lines = p.lines();
+    TEST_ASSERT_EQUAL_STRING("\xC3\xA9t\xC3\xA9", lines[0].c_str());
+    TEST_ASSERT_EQUAL_STRING("ici", lines[1].c_str());
+    TEST_ASSERT_EQUAL_STRING(" a.", lines[2].c_str());
+}
+
+// Scrolling down to the end and back up passes through the same line starts.
+void test_up_undoes_down() {
+    std::string text;
+    for (int i = 0; i < 300; i++) {
+        text += "line " + std::to_string(i) + " with some words to wrap around the edge of the screen";
+        text += i % 7 == 0 ? "\n\n" : "\n";
+    }
+    text += "a paragraph without any newline for a long while ";
+    for (int i = 0; i < 200; i++) text += "word" + std::to_string(i) + " ";
+    text += "\nthe end";
+    TextPager p = pagerFor(text, 38, 9);
+    std::vector<uint32_t> tops;
+    for (int guard = 0; guard < 5000 && !p.atEnd(); guard++) {
+        tops.push_back(p.top());
+        p.down();
+    }
+    TEST_ASSERT_TRUE(p.atEnd());
+    TEST_ASSERT_TRUE(tops.size() > 500);
+    TEST_ASSERT_EQUAL_STRING("the end", p.lines().back().c_str());
+    // Inside the long paragraph (further than the look-back from its start) lines may wrap from
+    // another place on the way up. Before it, every line start met on the way down is met again.
+    size_t paragraph = text.find("a paragraph without");
+    size_t expected = 0, met = 0;
+    for (uint32_t t : tops) expected += t <= paragraph;
+    for (int guard = 0; guard < 5000 && p.top() > 0; guard++) {
+        p.up();
+        if (p.top() > paragraph) continue;
+        TEST_ASSERT_TRUE(std::binary_search(tops.begin(), tops.end(), p.top()));
+        met++;
+    }
+    TEST_ASSERT_EQUAL_size_t(expected, met);
+    TEST_ASSERT_EQUAL_UINT32(0, p.top());
+    p.up();
+    TEST_ASSERT_EQUAL_UINT32(0, p.top());
+}
+
+void test_to_end_shows_the_last_lines() {
+    std::string text;
+    for (int i = 0; i < 100; i++) text += "20:0" + std::to_string(i % 10) + " <a> message " + std::to_string(i) + "\n";
+    TextPager p = pagerFor(text, 38, 9);
+    p.toEnd();
+    auto lines = p.lines();
+    TEST_ASSERT_EQUAL_size_t(9, lines.size());
+    TEST_ASSERT_EQUAL_STRING("20:09 <a> message 99", lines[8].c_str());
+    TEST_ASSERT_EQUAL_STRING("20:01 <a> message 91", lines[0].c_str());
+    TEST_ASSERT_TRUE(p.atEnd());
+    p.down();  // nowhere to go
+    TEST_ASSERT_EQUAL_STRING("20:01 <a> message 91", p.lines()[0].c_str());
+    TEST_ASSERT_TRUE(p.percent() > 80);
+}
+
+void test_a_megabyte_is_read_a_kilobyte_at_a_time() {
+    std::string text;
+    while (text.size() < 1024 * 1024) text += "2026-10-05 20:00:00 <someone> says something here\n";
+    reads = 0;
+    biggestRead = 0;
+    TextPager p = pagerFor(text, 38, 9);
+    p.toEnd();
+    TEST_ASSERT_EQUAL_size_t(9, p.lines().size());
+    p.up(20);
+    p.down(5);
+    TEST_ASSERT_TRUE(biggestRead <= 1024);
+    TEST_ASSERT_TRUE(reads < 20);
+    p.toStart();
+    TEST_ASSERT_EQUAL_STRING("2026-10-05 20:00:00 <someone> says", p.lines()[0].c_str());
+}
+
+void test_empty_and_short_files() {
+    std::string empty;
+    TextPager p = pagerFor(empty, 38, 9);
+    TEST_ASSERT_EQUAL_size_t(0, p.lines().size());
+    p.down();
+    p.up();
+    p.toEnd();
+    TEST_ASSERT_TRUE(p.atEnd());
+    std::string one = "no newline";
+    TextPager q = pagerFor(one, 38, 9);
+    q.toEnd();
+    TEST_ASSERT_EQUAL_STRING("no newline", q.lines()[0].c_str());
+}
+
+int main() {
+    UNITY_BEGIN();
+    RUN_TEST(test_lines_and_wrapping);
+    RUN_TEST(test_a_word_too_long_is_cut_and_a_space_at_the_edge_is_eaten);
+    RUN_TEST(test_accents_count_as_one_column_and_tabs_show_as_spaces);
+    RUN_TEST(test_up_undoes_down);
+    RUN_TEST(test_to_end_shows_the_last_lines);
+    RUN_TEST(test_a_megabyte_is_read_a_kilobyte_at_a_time);
+    RUN_TEST(test_empty_and_short_files);
+    return UNITY_END();
+}