Re: [OT] Bootable CD [Re: 2.3 wish: integrate pcmcia into mainstream

Chris Adams (cadams@ro.com)
3 Jun 1999 16:04:35 -0500


Once upon a time, Gerd Knorr <kraxel@goldbach.in-berlin.de> said:
>In lists.linux.kernel, you wrote:
>> I don't know if that's a limitation of mkisofs or of the El Torito/BIOS
>> specification,
>
>BIOS limit. The size must be *exactly* one of the three mentioned values.
>With 2.88 meg you'll have plenty of space, thats enouth for a compressed
>kernel and a compressed initrd with > 4MB space.

The El Torito spec has 4 options for emulation mode: 1.2, 1.44, or 2.88
MB floppy or hard drive. There is also another mode - raw CD (where x
number of sectors, up to 640K worth, are read into RAM and then just
run). This mode doesn't emulate a floppy or hard drive.

Now, I don't know what is actually _implemented_, but that is what the
spec says. It also has provisions for multi-image boot. It would be
nice if there was a way to call back to the real mode BIOS for things
like this (because then you _could_ load more). I know it would be an
ugly hack, but it would work for things like this.

BTW: I found the spec on the web at

http://www.cdpage.com/Compact_Disc_Variations/bootspec.pdf

-- 
Chris Adams <cadams@ro.com> - System Administrator
Renaissance Internet Services - IBS Interactive, Inc.
Home: http://ro.com/~cadams - Public key: http://ro.com/~cadams/pubkey.txt
I don't speak for anybody but myself - that's enough trouble.

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