Skip to content

Customising the Filesystem

Jump to bottom
Retro Jack edited this page Mar 27, 2026 · 20 revisions

Customising the Filesystem

The virtual filesystem is defined in prompt/index.html as a JavaScript array called fs. Everything — drives, directories, and files — lives in this one structure. No server or database required.

Finding the Filesystem

Open prompt/index.html and search for:

var fs = [{

Everything between that line and the closing }]; is the filesystem.

Adding a Link File

Link files open a URL in a new tab when executed.

Find the directory you want to add to and add a new entry to its files array:

{ name: 'GITHUB.COM', link: 'https://github.com/yourname' }

Example — adding a new emulator to C:\EMULATORS\DOS:

{
    name: 'DOS',
    directories: [
        ...,
        { name: 'QUAKE', directories: [], files: [{ name: 'quake.exe', link: 'https://archive.org/details/quake106' }] },
    ],
    files: [...]
}

The user can then cd\emulators\dos\quake and type quake to launch it.

Adding a Batch File

Batch files run a sequence of commands when executed. Commands are separated by \n.

{ name: 'HELLO.BAT', data: 'echo off\nsetcol 2e\necho Hello, world!\nsetcol 07\necho on' }

Supported batch commands: echo, echo off/on, cls, cd, dir, setcol, and any filename that exists in the current directory.

Example — a batch file that navigates and lists a directory:

{ name: 'GAMES.BAT', data: 'cls\ncd\\GAMES\ndir/w/o\n' }

Adding a Directory

Add an entry to the directories array of the parent directory:

{
    name: 'MUSIC',
    directories: [],
    files: [
        { name: 'SPOTIFY.COM', link: 'https://open.spotify.com/...' },
        { name: 'BANDCAMP.COM', link: 'https://yourname.bandcamp.com' }
    ]
}

Adding a System with a Games Submenu

Console systems use a two-level structure: a system directory containing a GAMES\ subdirectory. This is the same pattern used by all the built-in console entries (2600, NES, INTV, etc.).

{
    name: 'SYSTEM',
    directories: [
        {
            name: 'GAMES',
            directories: [],
            files: [
                { name: 'menu.bat', data: 'echo off\ncls\necho ÉÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍ»\necho º              SYSTEM  GAMES                  º\necho ÇÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄĶ\necho º                                             º\necho º   1.  GAME1     First Game Title            º\necho º   2.  GAME2     Second Game Title           º\necho º                                             º\necho ÇÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄĶ\necho º   0.  BACK      System Menu                 º\necho ÈÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍͼ\n' },
                { name: '0.bat', data: 'cd ..\nmenu\n' },
                { name: '1.bat', data: 'game1\n' },
                { name: '2.bat', data: 'game2\n' },
                { name: 'game1.bat', link: 'https://example.com/game1' },
                { name: 'game2.bat', link: 'https://example.com/game2' }
            ]
        }
    ],
    files: [
        { name: 'launch.exe', link: 'https://example.com/emulator' },
        { name: 'menu.bat', data: 'echo off\ncls\necho ÉÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍ»\necho º                  SYSTEM                     º\necho ÇÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄĶ\necho º                                             º\necho º   1.  LAUNCH    Launch Emulator             º\necho º   2.  GAMES     Browse Game Titles          º\necho º                                             º\necho ÇÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄĶ\necho º   0.  BACK      Parent Menu                 º\necho ÈÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍͼ\n' },
        { name: '1.bat', data: 'launch\n' },
        { name: '2.bat', data: 'cd games\nmenu\n' },
        { name: '0.bat', data: 'cd ..\nmenu\n' }
    ]
}

The user navigates like this:

menu        → system menu (Launch / Browse Games / Back)
2           → cd games && menu
1           → runs game1.bat (opens link)
0           → cd .. && menu (back to system menu)

Box-Drawing Menu Format

Menus use the CP437 box-drawing character set. The content area inside the box is exactly 45 characters wide.

ÉÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍ»    ← top border
º              CENTERED HEADER               º    ← 45 chars between º
ÇÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄĶ    ← separator
º                                             º    ← blank row
º   1.  CMDNAME   Title padded to 28 chars   º    ← entry row
º                                             º    ← blank row
ÇÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄĶ    ← separator
º   0.  BACK      Go Back                    º    ← back row
ÈÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍͼ    ← bottom border

Entry row layout (45 chars total inside the º borders):

Segment Width Example
Number prefix 7 1.
Command name (padded) 10 DOOM19S
Title (padded) 28 Doom v1.9

Single-digit: N. (7 chars) · Double-digit: NN. (7 chars)

Apostrophes in titles must be escaped as \' inside JS single-quoted data strings:

{ name: 'menu.bat', data: '...echo º   2.  KRAZYCH   K.C.\'s Krazy Chase!        º\n...' }

Adding Nested Subdirectories

Directories can be nested to any depth. Each directory object has its own directories array.

Example — a C:\GAMES tree with genre subdirectories:

{
    name: 'GAMES',
    directories: [
        {
            name: 'ACTION',
            directories: [
                {
                    name: 'FPS',
                    directories: [],
                    files: [
                        { name: 'doom.exe',   link: 'https://archive.org/details/The_Ultimate_Doom' },
                        { name: 'quake.exe',  link: 'https://archive.org/details/quake106.html' }
                    ]
                }
            ],
            files: [
                { name: 'sw.bat', data: 'cls\ncd\\GAMES\\ACTION\ndir/w/o\n' }
            ]
        }
    ],
    files: [
        { name: 'sw.bat', data: 'cls\ncd\\GAMES\ndir/w/o\n' }
    ]
}

Navigate using absolute paths:

cd\games\action\fps
doom

Tip: Files can only be executed from the directory they live in — there is no PATH support.

Executing Files via Batch

Because cd works inside batch scripts, a .BAT can navigate and run a file in one step:

{ name: 'doom.bat', data: 'cd\\games\\action\\fps\ndoom\n' }

Place it anywhere convenient and the user can type doom from any directory.

Syntax Behaviour
cd\\games\\action Absolute — always goes to C:\GAMES\ACTION
cd action Relative — only works if ACTION is a child of the current dir
cd .. Goes up one level

Always use absolute paths (starting with \\) in .BAT files to avoid broken navigation.

Changing the Boot Directory

AUTOEXEC.BAT runs automatically on load. It's defined in the root files array:

files: [
    { name: 'autoexec.bat', data: 'c:\ncd lgr\ncls\ndir/w/o\n' },
    ...
]

To boot into a different directory:

{ name: 'autoexec.bat', data: 'c:\ncd emulators\\dos\ncls\ndir/w/o\n' }

Setting a Custom Color Scheme

Use setcol in AUTOEXEC.BAT to set colors on boot. The argument is two hex digits: background then foreground.

{ name: 'autoexec.bat', data: 'echo off\nsetcol 17\nc:\ncd lgr\ncls\ndir/w/o\n' }
Code Background Foreground
07 Black Light Gray (default)
17 Dark Blue Light Gray
2e Dark Green Yellow
4e Dark Red Yellow
0a Black Green
0f Black White

See the Font System page for the full 16-color palette reference.

GenX-DOS

Internals

Emulators

Read more

Clone this wiki locally