Macintosh Classic Easter Egg - Secret Startup Disk in ROM

I have *two* Classics. It works on both of them. I think it's awesome!!!!

You may have reached the built-in Diagnostic Disk. This is programmed into an extra 128K of ROM memory, and is used to carry diagnostic programs used during burn-in testing and diagnosis. I have a Mac SE that this *may* work on, but I have not tried this yet.

DOURO, I hate to say it but you are wrong. The Macintosh Classic was code named the Macintosh XO during development, and was designed as a "diskless" workstation. The startup disk held in ROM has a special combination of system software designed specifically for the Macintosh Classic, and it contains just the components required to connect to an AppleTalk network. Its also very useful if the HDD on your Mac in toast and you need to run repair software. Another tip: If you start up from the disk, on a Mac without an HDD, then go to the apple menu -> then to control panel -> then to Startup Disk, you can set the ROM disk as startup disk and have it start up from ROM without having to hold down Apple+Option+X+O while it starts up. This doesnt have a lot of use on a Classic with a hard disk though :)

Proof: Select Boot Disk, click File, then get info. It says, "Where: hidden somewhere on this machine..."

i've got a mac SE and a mac classic, but my classic is acting up. whenever i start it, it won't load.

Actually, the ROM Disk in the Classic was a secret project that only a couple engineers knew about until it shipped. The reason it was added was because the ROM chip was 512K (16x256K), the original SE ROM (which this was based on) only required 256K bytes, and the engineer who did it had some extra night cycles to spend doing something fun. It was not part of any official Apple project. So this free 256K, plus around 50K from the SE photos, was used for the disk image (which was compressed) and ROM Disk driver. Apple-Talk was added as well, and the ability to save some info in PRAM. This enabled it to remember a network startup disk (plus any password required), and also saved the app name on the network drive and auto launch it (not sure if this was ever mentioned before :), making a turnkey system. It was also nice in case your hard drive crashed and you want to run some repair tools from a floppy. XO was the Classic code name, from a Cognac.