classiccmp-digest V1 #163

From: Derek Peschel <dpeschel_at_eskimo.com>
Date: Mon May 8 23:42:29 2000

David Greelish wrote:
> In a message dated Mon, 8 May 2000 00:27:26 -0400 (EDT), Sean 'Captain
> Napalm' Conner" <spc_at_armigeron.com> writes:
>
> << Again, to bring this back on topic, there have been plenty of operating
> systems distributed in ROM---AmigaOS, QNX, OS-9 and the original MacOS were
> all contained in ROM, were/are ROMmable and extensible. And all are older
> than 10 years old. Even MS-DOS came in ROM format for some computers
> (although I'm not sure if it ran out of ROM, or was copied to RAM before
> running). >>
>
> The Mac OS has never been fully contained in ROM. Starting with the Lisa in
> 1983 and the original Mac in 1984, Apple used a 64k ROM that contained GUI
> program routines (the Macintosh ToolKit). These machines still had to boot a
> floppy which made calls to the ROM.

Although this is true in a practical sense (especially because of the growth
of the OS), there is one exception I know of. On the original Mac Classic,
holding down Cmd-Option-X-O (the letter O) at boot time loads a small
version of the OS entirely from a disk image in ROM. (You can "Get Info" on
the disk and see an amusing note.) It may be System 6.0.2 or I could be
imagining that.

The new machines, on the other hand, load the "ROM" from disk and then write
protect the memory. Talk about going in the other direction...

-- Derek
Received on Mon May 08 2000 - 23:42:29 BST