Kevin O'Connor wrote:
> > SeaBIOS can be used for booting legacy OS and also Linux is still using
> > CMOS address 0x10 to configure floppy controller. Under these assumptions
> > it makes sense to allow boot from CMOS defined floppy drives.
>
> There was never really a standard for the layout of CMOS nor for the
> encoding of floppy type.
Ralf Brown's interrupt list disagrees:
--8<-- CMOS.LST
----------R10--------------------------------
CMOS 10h - IBM - FLOPPY DRIVE TYPE
Note: a PC having a 5 1/4 1.2 Mb A: drive and a 1.44 Mb B: drive will
have a value of 24h in byte 10h. With a single 1.44 drive: 40h.
Bitfields for floppy drives A/B types:
Bit(s) Description (Table C0007)
7-4 first floppy disk drive type (see #C0008)
3-0 second floppy disk drive type (see #C0008)
(Table C0008)
Values for floppy drive type:
00h no drive
01h 360 KB 5.25 Drive
02h 1.2 MB 5.25 Drive - note: not listed in PS/2 technical manual
03h 720 KB 3.5 Drive
04h 1.44 MB 3.5 Drive
05h 2.88 MB 3.5 drive
06h-0Fh unused
SeeAlso: #C0007
-->8--
> Currently, SeaBIOS doesn't use CMOS for anything when configured for
> coreboot mode and I think we should keep it that way.
The first either 15 or 48 bytes are explicitly reserved on all
coreboot mainboards and coreboot checksums bytes 16-45 when built
to use an option table.
> If you have a machine with a floppy drive that you'd
> like to use with coorboot+SeaBIOS then you can set the "etc/floppy0"
> or "etc/floppy1" cbfs files to activate support in SeaBIOS.
That's fine, but why reject the de-facto standard method?
Kind regards
//Peter
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