Infinite Mac URL Query Parameters Complete Reference

All configuration of an Infinite Mac session is URL-driven. The runDefFromUrl function in src/defs/run-def.ts parses every supported parameter from the URL and assembles a RunDef object that drives the emulator. The inverse, runDefToUrl, serialises a RunDef back to a URL — both functions are the authoritative source of truth for the parameter names and their accepted values documented on this page.

URL patterns

Infinite Mac recognises two URL shapes. Year-path URLs select a pre-bundled system disk by year and name:

https://infinitemac.org/<year>/<disk-name>

For example: https://infinitemac.org/1991/System%207.0 With year-path URLs, infinite_hd and saved_hd both default to true; pass false explicitly to disable them. Custom-run and embed URLs allow full configuration via query parameters:

https://infinitemac.org/run?...
https://infinitemac.org/embed?...

The /embed variant activates embed-specific behaviour (screen fills the iframe, library drawer is hidden, default EmulatorSettings are applied). Every parameter below works with either path unless noted otherwise.

Disk Selection

disk

string

The displayName of a built-in system disk to include (e.g. "System 7.5", "Mac OS 9.0.4"). May be repeated to include multiple disks. The first disk determines the preferred machine if machine is not also specified.

disk_url

string

URL of an external disk image to mount. May be repeated for multiple external disks. The image must be reachable from the emulator’s origin, so CORS headers are required for cross-origin URLs.

disk_prefetch

string

Comma-separated list of chunk indices to prefetch for the corresponding external disk, e.g. "0,1,2". Position-matched with disk_url — the first disk_prefetch applies to the first disk_url, the second to the second, and so on. May be repeated.

Machine

machine

string

The exact name of a MachineDef to use, overriding the disk’s preferred machine. Examples: "Quadra 650", "Power Macintosh G3 (Beige)", "Mac Plus". Setting this parameter also marks the run as custom.

ram

string

RAM size override for the selected machine. The value must be one of the sizes listed in that machine’s ramSizes array. Examples: "128K", "8M", "32M", "256M". If the value is not present in the machine’s supported sizes it is silently ignored.

Screen

screenSize

string

Controls how the emulated screen is sized. Accepted values:

Value	Behaviour
`auto`	Default for `/run` URLs. The screen adapts to the window.
`window`	Screen fills a floating window within the page.
`fullscreen`	Screen expands to fill the browser viewport.
`embed`	Set automatically for `/embed` URLs; fills the iframe dimensions.
`WxH`	Fixed resolution, e.g. `"800x600"` or `"1024x768"`.

When embedding, the iframe’s own width and height attributes determine the emulated screen resolution unless you specify an explicit WxH value.

screen_scale

number

Pixel scale factor applied to the emulated display, e.g. 2 for 2× integer scaling. At scale 2 you should also double the iframe’s width and height so that the logical resolution remains unchanged while the rendered output is crisper. Also accepted as screenScale (camelCase).

Storage

infinite_hd

boolean

Whether to mount the Infinite HD virtual hard disk, which contains thousands of classic Mac applications drawn from the Macintosh Garden archive. Defaults to true for year-path URLs and false for /run//embed URLs. Pass "true" or "false" explicitly to override.

saved_hd

boolean

Whether to mount the Saved HD persistent disk whose contents survive across sessions in the browser’s local storage. Defaults to true for year-path URLs and false for /run//embed URLs.

library

boolean

Whether to show the Macintosh Garden library drawer that lets users browse and load software at runtime. Defaults to true; pass "false" to hide it. The drawer is always hidden in embed mode (/embed URLs).

library_url

string

URL of a Macintosh Garden library item to pre-download when the session starts. The item will be available in the library drawer immediately without requiring the user to initiate a download. May be repeated.

CD-ROMs

cdrom

string

URL of a CD-ROM disk image to mount. Also accepted as cdrom_url. May be repeated to mount multiple CD-ROMs.

cdrom_url

string

Alias for cdrom. Both parameter names are collected and merged into a single list of CD-ROM URLs.

cdrom_prefetch

string

Comma-separated list of chunk indices to prefetch for the corresponding CD-ROM image, e.g. "0,1,2,3". Position-matched with the merged list of cdrom/cdrom_url values. May be repeated.

CD-ROM mounting is not supported by DingusPPC or PearPC. It is also unavailable on Snow-backed machines that lack SCSI support, and on sessions using a disk with an MFS (Macintosh File System) subset.

Networking

appleTalk

string

AppleTalk zone name for local networking via the Cloudflare Worker ethernet provider. All sessions that share the same zone name can communicate with each other over a virtual LocalTalk network.

broadcast_channel_ethernet

boolean

Set to "true" to use the BroadcastChannel API for local networking instead of the Cloudflare Worker provider. This keeps traffic entirely within the browser and is useful for connecting multiple tabs or iframes on the same origin without a server.

Playback

paused

boolean

Set to "true" to start the emulator in a paused state. The machine will not execute until an emulator_unpause control event is received, or the user manually resumes it.

auto_pause

boolean

Set to "true" to automatically pause the emulator when it scrolls out of the browser viewport and resume it when it scrolls back in. Useful for reducing CPU usage on long pages that contain multiple embedded instances.

Embed-specific

screen_update_messages

boolean

Set to "true" on /embed URLs to enable emulator_screen postMessage notifications. When active, the emulator posts a message to the parent page containing raw RGBA pixel data each time the screen changes. See Notification Events for details on how to receive and render these frames.

Debug

date

string

Override the emulated machine’s clock with a specific date. The value is parsed by the fromDateString helper in src/lib/dates.ts. Useful for reproducing date-sensitive bugs or testing software that behaves differently on specific calendar dates.

debug_fallback

boolean

Set to "true" to force the non-SharedArrayBuffer fallback execution mode, even when SharedArrayBuffer is available. This replicates the degraded performance environment seen by users whose hosting environment does not set the required Cross-Origin-Embedder-Policy header.

debug_audio

boolean

Set to "true" to enable verbose audio debug logging in the browser console.

debug_log

boolean

Set to "true" to enable verbose emulator-level logging in the browser console. Effective for DingusPPC, Previous, and PearPC; has no effect on other emulator backends.

debug_paused

boolean

Set to "true" to start with the emulator’s main loop paused at the very first iteration, before any machine code has executed. Unlike the paused parameter (which pauses after the machine is running), this halts execution at the lowest level before the emulator loop begins.

debug_trackpad

boolean

Set to "true" to enable the trackpad debug overlay, which renders a visual indicator of pointer position and touch state on top of the emulated screen.

blue_scsi

boolean

Set to "true" to enable BlueSCSI support for the DingusPPC emulator. Only recognised when the active emulator backend supports optional BlueSCSI (emulatorHasOptionalBlueSCSI returns true).

settings

string

A JSON-encoded EmulatorSettings object that overrides the default emulator settings. Unrecognised keys are ignored; recognised keys are merged over the defaults. The EmulatorSettings type is defined in src/emulator/ui/settings.ts:

type EmulatorSettings = {
  swapControlAndCommand: boolean; // default false
  speed: EmulatorSpeed;           // default -2
  useMouseDeltas: boolean;        // default false
  trackpadMode: boolean;          // default false
  screenScaling?: 'auto' | 'smooth' | 'pixelated';
};

Example value: {"swapControlAndCommand":true,"speed":0}

edit

boolean

Set to "true" to open the custom configuration dialog pre-populated with the parameters from the current URL. Also marks the run as custom (isCustom: true), which switches the URL display to the /run?... form.

Example URL

The following embed URL starts a Quadra 650 running System 7.5, mounts the Infinite HD, pre-downloads a Macintosh Garden item, enables persistent storage, starts paused, uses 2× pixel scaling, and enables screen frame notifications:

https://infinitemac.org/embed
  ?machine=Quadra%20650
  &disk=System%207.5
  &infinite_hd=true
  &saved_hd=true
  &library_url=https%3A%2F%2Fmacintoshgarden.org%2Fapps%2Fsimcity-2000
  &paused=true
  &screen_scale=2
  &screen_update_messages=true

As a single line (for use in an <iframe src="..."> attribute):

https://infinitemac.org/embed?machine=Quadra%20650&disk=System%207.5&infinite_hd=true&saved_hd=true&library_url=https%3A%2F%2Fmacintoshgarden.org%2Fapps%2Fsimcity-2000&paused=true&screen_scale=2&screen_update_messages=true

Machines & Disks

Embed API

Infinite Mac URL Query Parameters Complete Reference

URL patterns

Disk Selection

Machine

Screen

Storage

CD-ROMs

Networking

Playback

Embed-specific

Debug

Example URL

Build docs developers (and LLMs) love

Machines & Disks

Embed API

Documentation Index

​URL patterns

​Disk Selection

​Machine

​Screen

​Storage

​CD-ROMs

​Networking

​Playback

​Embed-specific

​Debug

​Example URL

Build docs developers (and LLMs) love

URL patterns

Disk Selection

Machine

Screen

Storage

CD-ROMs

Networking

Playback

Embed-specific

Debug

Example URL