jkg@pyr.gatech.EDU (Jim Greenlee) (07/23/87)
It appears that I may have jumped the gun a little on my recent posting
concerning upgrading to ROM BIOS 1.43. My long-awaited hardware reference
manual came today, and it contains lots of interesting information about
hard disks and controllers and other related stuff.
Apparently there is a jumper (labeled W3) on the Western Digital controllers
that enables/disables the ROM on the controller card. On my disk controller
this jumper is missing (the solder pads on the PC board are connected by a
trace, which causes the controller ROM to be enabled).
It appears that all I have to do to enable the ROM routines on the mother-
board is cut this trace, install shorting blocks for the appropriate drive
type, and set the DIP switch on the motherboard (switch 3 in bank 1) to
select internal BIOS code for the hard disk.
Before I go hacking up one of my PC boards, can anybody confirm or deny that
this procedure will work? I should point out that it is sufficient to say
"I did it on my PC 6300 and it worked for me" - I promise not to hold anybody
personally responsible if they say it will work and it doesn't. I just want
to make sure that I'm barking up the right tree. Thanks.
Jim Greenlee
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oebxr vg, qvqa'g lbh?!spud@oliveb.UUCP (John Purser) (07/24/87)
In article <3838@pyr.gatech.EDU> jkg@pyr.UUCP (Jim Greenlee) writes: > >Apparently there is a jumper (labeled W3) on the Western Digital controllers >that enables/disables the ROM on the controller card. On my disk controller >this jumper is missing (the solder pads on the PC board are connected by a >trace, which causes the controller ROM to be enabled). > >It appears that all I have to do to enable the ROM routines on the mother- >board is cut this trace, install shorting blocks for the appropriate drive >type, and set the DIP switch on the motherboard (switch 3 in bank 1) to >select internal BIOS code for the hard disk. > > Jim Greenlee > Is the ROM on the WD board socketed or soldered? If it's socketed I would just pull it out of the socket rather than cut the trace. The power on routine of the BIOS won't find the WD ROM if its been pulled from the socket so by default it will use the motherboard ROM BIOS. At power on time the BIOS startup routine looks through segments C000, D000, and E000, for valid option ROMS. The details of the address space that is searched and what makes up a valid option ROM are in your tech. ref. somewhere. When a valid option ROM is located it is called from the motherboard BIOS. The option ROM can then do any inititialization neccesary and retrun to the motherboard BIOS. In the case of your WD controler the initialization code will re-vector int 13h to the WD BIOS on the controler board. So by removing the WD BIOS you've solved your problem. If the WD BIOS is soldered then see if you can't find a schematic for the controller. I think you would find that the trace you have suggested cutting goes to the chip select line of the WD BIOS. I'm not an EE and I don't have a good understanding of schematics and board layout but I think that cutting the trace would also work. Pulling the WD BIOS is more easily reversable though. Good Luck, Have fun. John Purser