ATA Bus Wierdness

After doing a data recovery and restore to a hard drive in a Power Mac G4 (Mirrored Drive Doors 2003) 1.2Ghz, I put the drive back in the unit and booted up from a 9.2.1 Universal disk I make a while back. The drive was not recognized when booted from CD, and Drive Setup didn't even know it was there. I pulled it out again and plugged it back in. The drive was plugged in to the IDE connector nearest the processor, and I noticed that there was an ATA/66 connector available next to where the CD/DVD plugged in. It still didn't work. Hmmm....

I plugged the drive in to the ATA/66 and it showed up. I was getting ready to tell the client that the logic board would need repair when it occurred to me that maybe my "Universal" boot CD wasn't so universal. After verifying that the System Folder on the HD was blessed, I booted from the hard drive itself. Since it worked fine in ATA/66 slot, I decided to give it one last go in the other slot— an Ultra ATA/100 slot. It booted right up.

So, just because a CD boots a computer, doesn't mean it supports all of its components. Just because you've found a problem, doesn't mean you really know what it is, or that it is the only problem you have. In my case my "Universal" boot CD didn't support the Ultra ATA/100 hard drive bus, and what appeared to me to be a bad logic board, was simply lack of support for the bus in question. Don't jump to conclusions, always find more than one way to verify your suspicions.