What is HostFS?

HostFS lets a folder you pick in the browser appear to the guest as a single drive (e.g. C:), without going through a disk image — you can dir, type, and copy files straight out of that folder. Use the "HostFS" row below the SCSI row at the bottom of the player.

Supported on Chrome-family browsers on PC and Android (any browser with showDirectoryPicker). Not supported on iPhone (Safari) or Firefox.

First-time setup

1Show the HostFS row

Open the "…" menu → "Display" group → "Show HostFS". If a folder is connected, the row also appears automatically even while it's waiting to reconnect.

2Connect a folder

Click the "Connect a folder" button (an icon; hover to see its name) on the HostFS row — a dialog asks whether to connect read-only or with writes allowed. Choose one, optionally jot down a note, then pick the folder.

3Install HostFS onto a disk

Open the "Disk Library" and click "Install HostFS" on the bundled disk's row (human302.xdf). Confirm with "Yes", and a new row, human302-hostfs.xdf, appears in the library. It is not inserted automatically. The bundled disk itself is never modified.

4Insert into FDD0

Click "To FDD0" on the new human302-hostfs.xdf row. The library closes automatically.

5Boot

If not already running, click "Boot with the Selected Disks" on the start overlay. If already running, click the round arrow (Reset) at the right end of the toolbar.

6Check the banner

The startup screen shows "HostFS version 1.00 (WebX68k)" followed by a line meaning "host folder assigned to drive C:" (it can be D:, etc., if an HDD is present).

7Try it

Type dir c: at the guest's command line to see the folder's contents.

Using it after the first time

After reopening the page, reinsert the already-installed human302-hostfs.xdf from the disk library using "To FDD0", then boot. The folder reconnects automatically at boot. If the browser asks for permission again, a "Reconnect (permission needed)" button (an icon) appears on the HostFS row — click it.

Connecting a folder after boot also works without a reset, as long as you're running from a disk that already has HostFS installed.

Installing onto your own disk (an HDD, or an FD usable as FAT12/16)

For the guest to use HostFS, the boot disk's CONFIG.SYS needs the line DEVICE = \HOSTFS.SYS. The "Install HostFS" button on each disk library row (HDD, or an FD that can be handled as FAT12/16) writes HOSTFS.SYS to that disk and adds this line to CONFIG.SYS automatically (appended if CONFIG.SYS already exists, created new otherwise; it won't be added twice if the line is already there). Pressing "Install HostFS" again on a disk that already has an older HOSTFS.SYS replaces just that file with the new version (the CONFIG.SYS line is not duplicated).

Troubleshooting

Driver-not-installed warning: If a folder is connected but the disk you booted doesn't have HostFS installed (the guest's HOSTFS.SYS hasn't loaded), the row shows "⚠ HOSTFS.SYS is not loaded in the guest". Boot from a disk that has HOSTFS.SYS installed, using "Install HostFS" above. The warning clears once it loads, and a reset or reboot puts it back into "waiting" state.

Seeing "invalid drive specification": If you're running from a disk that doesn't have HostFS installed, dir c: fails with "invalid drive specification" and the HostFS row shows the warning above. Reboot from a disk that has HostFS installed instead.

Hidden-name notice: If a listing (dir, etc.) had to drop names that don't fit Human68k's 8.3 format, the row shows "N name(s) not shown". Hover to see the combined list from every folder listed so far, each shown as a path relative to the connected folder (/subfolder/name, one per line; up to 20 lines, with "N more" beyond that). Listing a given folder again replaces just that folder's entries with the latest contents.

Unsupported-request warning: If a resident program or similar sends HostFS a request we haven't decoded yet, the row shows "⚠ Unsupported request ($xx)" (or "⚠ Unsupported request ($xx, +N more kinds)" when more than one kind has been seen). If you see this warning, please click the row to copy diagnostic info to the clipboard, and attach it when reporting the issue on GitHub. The copied text only contains the build stamp, the browser's User-Agent, the request number/count/first 26-byte header/[if applicable] the 32 bytes at the pointer it carries, and HostFS's own state (driver detected, drive number, folder connected, mode). It never includes file names inside the folder, the note text, or the folder's actual host-side path. On environments without clipboard access, a small dialog opens instead with the text ready to select and copy. A reset or reboot clears the recorded requests.

Things to know

Host file names are converted to Human68k's 8.3 format (8-character name + 3-character extension, at most one dot) before being shown. A name is omitted from listings if any of the following hold: extension is 4+ characters / name is over 18 bytes (Japanese characters are 2 bytes each) / more than one dot / starts with a dot / contains any of " * + , / : ; < = > ? [ ] | / contains a character not representable in CP932 (spaces are fine). Line endings are not converted — the host's byte stream is passed through as-is.

Note: The File System Access API only hands you the folder's name, not its full host-side path (where it actually lives). You can jot down a note (optional, up to 60 characters) in the "Connect a folder" dialog's note field; the row then shows "folder name — note" (truncated with an ellipsis when long, with the full text in a tooltip). Edit it later from the pencil icon on the row.