Gigabyte BXDU and BXDS motherboards

These have long been favorite motherboards of mine, and I still have several in operation. They have two slots (yes, slots - slot 1 to be specific) for Pentium II or III processors. They also have onboard adaptec SCSI controllers. They used the Intel i440BX chipset. If it were not for the on-board scsi, I am sure they would have been junked years ago.

Here are some manuals as PDF files:

The BXDU and BXDS are identical, except that the DS does not do ultra speed SCSI.

Processors

The fastest processor I ever heard of in this motherboard was a 600 Mhz, but apparently it will accept 1.0 Ghz processors in the "Coppermine" family with a 100 Mhz bus setting. The use of 400 or 450 processors were common. This board will not run the memory bus at 133, you must use 133.

On board SCSI

The SCSI subsystem used an Adaptec AIC-7896 chipset. There were always issues with boot devices on these systems. The SCSI bios and the Award bios on these boards were scarcely aware of each other, which always led to confusion and frustration.

There are two scsi channels (A and B), which can each support 15 targets, so in theory you can have 30 scsi devices in one of these systems. Channel B has a wide (68 pin) and a "regular" (50 pin) scsi connector. Channel A has a pair of wide (68 pin) connectors. Termination was always something to take care to get right. The bus should be terminated at each end (but because the controller has a pair of connectors for each bus, it may end up in the middle of the bus, and if so, should not have termination enabled. Termination (at the controller) can be selected from the BIOS menu in the "Integrated Peripherals" section. Channel A termination can be enabled or disabled. Typically it would always be enabled, it would only be disabled if both Channel A connectors were used and external terminators were in place at the end of both of those cables. Channel B termination can be both, high byte, low byte, or none. Typically this would be set to both, the only time it would not be would be when both connectors were used and terminated at their ends.

ATA (IDE) subsystem

These boards have a pair of 40 pin EIDE connectors. These boards can boot just fine from a DVD rom, and this is how I install linux on them.

Tips and tricks

Setting up a linux system on one of these boards is always interesting. There are unfathomable mysteries about how the boot device is selected given that the Award bios handles part of the game (including IDE devices), and the Adaptec bios handles the other part. If you try to mix IDE and scsi disks, things will not be pretty.

What works for me is to do the install on a scsi drive (as root), then add an IDE device later, but not on the primary IDE. I believe the bios will only ever try to boot from and IDE disk if it is the primary master, but don't try to come and sue me if this doesn't work out.

The other interesting thing is that you can boot from the CDROM or you can boot from the SCSI, but the bios has no selection that says to first try the CDROM then go to the SCSI if it ain't there. This means you have to change the bios settings to install and boot from the CDROM (or DVD), then change them back to boot from the scsi disk - and change them again if you ever want to boot from the CDROM, and so forth, ad nauseum. Fortunately, I usually just install from CDROM, change the setting, and live happily ever after.

Have any comments? Questions? Drop me a line!

Adventures in Computing / tom@mmto.org