Syslinux - Feb 2008 - isolinux not booting - old 486 with SCSI CD writer

I am trying to install Debian Linux on an an old Intel Classic R+ computer that
uses an internal Yamaha SCSI CD writer model CRW8424S connected to an Adaptec
ISA SCSI card (I think its a 1542CP). The CD writer is is the only device
connected to the SCSI card. The computer has one hard drive connected to the
on-board IDE interface, a 1.44MB 3 1/2 inch floppy and a 1.2MB 5 1/4 inch
floppy.
The hard drive is 1.6GB and contains EZ-Drive as the BIOS only supports drives
up to 500MB approx. However, EZ-Drive only loads when booting from hard drive.

During the boot the following messsages were output by the Adaptec BIOS
   Press ^A for SCSISelect(TM) Utility!>>>
SCSI ID #1 - Yamaha CRW8424S
A BOOTABLE CD-ROM IS DETECTED IN YOUR CDROM DRIVE.
The boot sections on your bootable CD-ROM are:
       0. DEFAULT ENTRY
YOUR CD-ROM DRIVE IS INSERTED AS - DRIVE D:(81h)
BIOS Installed Successfully.

Once the BIOS had finished I received the following messages
ISOLINUX 3.51 2007-06-10 isolinux: Loading spec packet failed, trying to wing
it.
...
isolinux: Found something at drive = 81
isolinux: Failed to locate CD-ROM device; boot failed.
See http://syslinux.zytor.com/sbm for more information.

The Microsoft Windows 98SE installation CD does boot on this computer.

I downloaded syslinux-3.61 and made a CD that used the debug version. The
messages
from this were
ISOLINUX 3.61 2008-02-03 Copyright (c) 1994-2008 H. Peter Anvin
isolinux: Starting up, DL = 01
isolinux: Loading spec packet failed, trying to wing it...
isolinux: Trying BrokenAwardHack first ...
isolinux: BAH: Original Int 13 vector : DC002343
isolinux: BAH: FAILURE
isolinux: Found something at drive = 81
isolinux: Failed to locate CD-ROM device; boot failed.
See http://syslinux.zytor.com/sbm for more information.

Having found the ?El Torito? Bootable CD-ROM Format Specification
http://www.phoenix.com/NR/rdonlyres/98D3219C-9CC9-4DF5-B496-A286D893E36A/0/specscdrom.pdf
I made changes to isolinux.asm to display the spec packet and accept drive 81h.
I've attached a diff of my changes.

Using the changed isolinux (again debug version) the last few lines were
isolinux: Found something at drive = 81
   13 00 00 00 00000047 01 00 0000 0000 0004 57 A0 3F 00
isolinux: Loading main image from LBA = 00000048
isolinux: Sectors to load = 0006

The computer then sits there continuously accessing the CD drive.
The computer did reboot when Ctrl-Alt-Del was pressed.

I tried again. This time I ejected the CD when the computer was
continuously accessing the CD drive. This resulted in the following message
isolinux: Disk error 80, AX = 420081

I don't have time to continue at the moment. Does any one have any good
references on the BIOS functions used or suggestions as to how to continue
when I do have time.

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Bruce Robson wrote:
> 
> The Microsoft Windows 98SE installation CD does boot on this computer.
> 
But not the Windows 2000 CD, I bet.

I think you have one of the old machines which only could boot from a CD 
in floppy emulation mode.  Those will not work with isolinux (without 
SBM), but you can create a floppy image using SYSLINUX and boot it.

There were a lot of such crappy bioses until Microsoft started using El 
Torito native mode, at which point they quickly got fixed.

	-hpa

Bruce Robson wrote:
> I am trying to install Debian Linux on an an old Intel Classic R+ 
> computer that uses an internal Yamaha SCSI CD writer model CRW8424S
 > connected to an Adaptec ISA SCSI card (I think its a 1542CP).
 > The CD writer is is the only device connected to the SCSI card.
 > The computer has one hard drive connected to the on-board IDE
 > interface, a 1.44MB 3 1/2 inch floppy and a 1.2MB 5 1/4 inch
 > floppy. The hard drive is 1.6GB and contains EZ-Drive as the
 > BIOS only supports drives up to 500MB approx. However,
 > EZ-Drive only loads when booting from hard drive.
> 
<snip>
> Using the changed isolinux (again debug version) the last few lines were
> isolinux: Found something at drive = 81
>   13 00 00 00 00000047 01 00 0000 0000 0004 57 A0 3F 00
> isolinux: Loading main image from LBA = 00000048
> isolinux: Sectors to load = 0006
> 
> The computer then sits there continuously accessing the CD drive. 
<snip>
> I don't have time to continue at the moment. Does any one have any good
> references on the BIOS functions used or suggestions as to how to continue
> when I do have time. 
I found that the problem that caused the computer to sit there
continuously accessing the CD drive was that all the extra
print code I inserted meant that variable MaxTransfer was
no longer in the first 2k. Hence it did not get initialised.

Now that I have removed the code to print the spec packet,
my modified isolinux based on syslinux-3.61 works.

I've attached a diff of my changes. The first two changed
lines fix a comment and the 13 v 13h bug I raised in another
thread. The remaining changes fix my initial problem of
isolinux not finding my CD drive.


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Bruce Robson wrote:
> 
> I made changes to isolinux.asm to display the spec packet and accept 
> drive 81h.
> I've attached a diff of my changes.
> 
Could you re-send this as a unified diff (diff -u)?

	-hpa