I had that happen too many times. normaly when my drive was on its way out, those machines are so **** unreliable its unreal (there must be enough heads whove encountered no problems at all with em, im envious..)
anways.. if your gonna buy a new drive, ditch SCSI and get a CF reader, serious, then all you need is one card, and archive all your APS&SEQ and samples on your pc. brought a £12 USB CF reader, for the pc, and that reads everything str8 off the CF hard, its very quick transfering to and from too. shit used to take ages saving / loading from zipz and stuff....
rant over...