AltirraSDL

Where your files live

AltirraSDL runs entirely in your browser, so there is no download folder on your hard disk. Everything you upload is stored in IndexedDB, a per-site database the browser keeps for this page. Files survive page reloads, browser restarts, and even computer reboots — but they are tied to this exact origin (the site URL). Visiting from a different browser, profile, or device shows an empty library.

Internally the emulator mounts that database as a Unix-style tree at /home/web_user/. Each category in the sidebar is a real folder there (/games, /disks, /firmware, etc.), which is why renaming, moving and creating folders all behave like a regular file manager.

Storage usage & quotas

The bar at the bottom of the File Manager shows how much browser storage your library is using and how much the browser is willing to give you. Browsers do not advertise a fixed cap — they offer a sliding quota based on free disk space, and they may evict the data of less-used origins when the disk fills up.

• 🔒 Persist — clicking this asks the browser to mark your library as persistent. Persistent storage is not evicted automatically; the browser will only delete it if you ask it to. Click the pill once and it changes to a green ✓ when granted. Some browsers (notably Safari and Firefox in Private Mode) refuse the request silently; that is normal — your files are still kept until storage pressure forces an eviction.
• Bar colour — green/blue when comfortable, amber past 75% of the offered quota, red past 90%. If the bar turns red, free space by deleting items you no longer need or by using 🗑 Wipe… to reset categories.
• Need more space? Browsers grow the quota automatically as your free disk space allows. There is no manual "request more" API beyond the persist upgrade. To make room, free space on the underlying disk and the quota will rise on the next estimate.

Adding files (4 ways)

• 📁 Upload… — opens your operating-system file picker. Multi-select is supported. Files are routed by extension into the right category, unless you uploaded from inside a folder view (then they land in that folder).
• 🔗 From URL… — fetches a file straight off the web into your library. Useful for direct links from public archives. The remote server must send permissive CORS headers; if it doesn't the download fails with a dedicated explanation.
• Drag & drop — drop files from your desktop or another browser tab onto the canvas (auto-categorize) or onto the open File Manager (lands in the current folder or filter).
• Bulk archives — drop a .zip in the Archives folder and use 📦 Unpack from the batch toolbar to expand it into a sibling folder.

Using "From URL…"

Paste a direct link to a file. The dialog shows where the file will land (the current folder when you opened the dialog from inside one, or the auto-categorize router by extension). The download streams directly into the virtual filesystem with a live progress bar.

About CORS errors — browsers refuse to read the body of a cross-site fetch unless the server explicitly opts in with Access-Control-Allow-Origin. Public archives and CDNs (ifarchive.org, ibiblio.org, GitHub releases, archive.org…) usually do; personal hosting, Dropbox/Google Drive share links, and most game-site download pages don't. If a download fails with a CORS message, the cleanest workaround is to download the file in a new browser tab and then drop it onto the File Manager.

Organizing & cleaning up

• ＋ New Folder — create folders inside any category or anywhere under All files.
• ☑ Select — enables checkboxes so you can multi- select files for cut, copy, paste, move, unpack or delete operations.
• Cut / Copy / Paste — shortcuts Ctrl/Cmd+X, Ctrl/Cmd+C, Ctrl/Cmd+V. Cut entries are dimmed until pasted.
• Rename — F2 on a single highlighted row.
• Delete — Delete key on the highlighted row(s); folders are removed recursively.
• 🗑 Wipe… — one-shot reset. The dialog offers "Wipe uploaded files" (keeps emulator settings) and "Reset to factory" (deletes everything including settings and the first-launch ROM marker).

Saving files back out

Hover any file row and click ⬇ Download (the icon appears on hover) to save the in-browser copy back to your operating-system Downloads folder. This is the bridge for getting save-states, screenshots and edited disks back out of the sandbox.

Keyboard shortcuts

• Esc — close the topmost dialog
• Ctrl/Cmd+X / C / V — cut / copy / paste
• Delete — delete highlighted entries
• F2 — rename highlighted entry

Things that go wrong

• Files vanished after relaunch — you may be in a private/incognito window. Those windows give every site a temporary IndexedDB that is wiped on close.
• Browser asked to "free up space" — accept the prompt for unrelated sites first. If your library is the one being evicted, click 🔒 Persist next time.
• Upload fails with "QuotaExceededError" — your browser hit the soft quota. Free disk space on the host system or remove large items from the library.
• "From URL" failed with no body — almost always CORS. See the URL section above.