29 Dec
2000
29 Dec
'00
4:16 p.m.
However I have
no info on whether it would be possible to add a SCSI
card to an IBM-PC. I have an Adaptec 1522A ISA SCSI card and likely
others in my card box. Was there a SCSI card for the PC ? If so,
would this possibly, with this configuration, allow you to transcend
the 5-slot limits of the PC. And of course to have 1 meg storage for
programs. WHEEEEE!!!
I think it's possible, although I have no idea if a commercial card
was ever produced.
SCSI-1 had an 8 bit databus, and there were a number of SCSI interface
chips that also used an 8 bit databus on host side -- the most common
being the well-known NCR 5380. Sticking one of those on an 8 bit ISA
card is not hard -- in fact I've seen cards like that.
All versions of the PC BIOS after the original one support BIOS
extension ROMs on peripheral cards. This is needed to boot from any
device other than a standard floppy drive -- basically the PC
motherboard BIOS knows how to boot floppy drives and nothing else. If
you want to boot from a hard disk or something, then the hard disk
controller needs to have a BIOS extension ROM that (amongst other
things) contains drivers for that controller.
So in theory it's possible to make an 8 bit SCSI controller with the
necessary extension ROM to allow the PC to boot from a SCSI drive.
I have never seen one (all the 8 bit SCSI cards I have don't have a
BIOS extension ROM on them), but that doesn't mean they don't exist.
-tony