Hardware compatiblility

I’ve spent a substantial chunk of this weekend upgrading a server which was somewhat lacking in discspace.

It’s a fairly old machine and as such doesn’t have SATA, but that’s not a showstopper. One PCI SATA card later, and a couple of 2TB SATA hard drives, and it’s good to go. In theory.

Except the SATA card was failing to recognise the hard drives.

I wanted to see if upgrading the BIOS in the SATA card would help, but unfortunately while I could find a newer BIOS image from the chipset manufacturer, the card manufacturer had used an unsupported flash chip and so their flash utility wouldn’t work. The card manufacturer hasn’t published their own on their website, so no go there.

I also wanted to see if upgrading the BIOS in the motherboard would help. It was hard finding a floppy disc that wasn’t unformattable due to age, and the BIOS is old enough that while it can boot from a USB floppy drive, it didn’t like the modern USB memory stick that I tried. Eventually I found a floppy that just about worked, and got the BIOS upgraded.

That didn’t help.

I then noticed that I had another machine with the exact same motherboard. I plugged the SATA card into that one, and lo and behold it recognised the drive.

I stripped the machines down to more or less the bare minimum, swapped every component I could (even down to the power supply) and still, one machine found the hard drives, and the other didn’t. After swapping the motherboards, neither worked.

Eventually, after a lot of head-scratching, I discovered the difference.

One of the machines was used as a desktop PC, and hence had a mouse plugged in.

Plugging a mouse into the server made it spring into life, and for as long as a mouse is plugged in, it reliably detects the SATA drives and boots happily.

To say that I am confused by this behaviour is an understatement. But there you have it, a mouse makes SATA go.

The motherboard in question is an ASRock K7S8X. The SATA card is a Lycom ST-125 (based on the Silicon Image 3124 chip). The drives are WD Caviar Green 2TB.

If you think you can explain this behaviour, please do leave a comment.

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