jesup@cbmvax.commodore.com (Randell Jesup) (07/31/90)
In article <3757@tmiuv0.uucp> rick@tmiuv0.uucp writes: >Quantum drives don't actually do a low-level format. Essentially, they >recalibrate (reseek track 0) and report "Done". There are a few other >drives which do this. "SCSI is a standard that isn't". > >To my knowledge, the only way to low-level format a Quantum is to send it >back to Quantum. Also, since no low-level format is actually done, Quantums >are prime candidates for the "0 in block 0" FFS bug. There are other drives >with the same problem. Hey, SCSI drive makers: either implement the command >or refuse it. Don't fake it out. It seems that several of the manufacturers >merely take the SCSI standard as a "strong suggestion". Perhaps we need a >new division of the police known as the "SCSI Squad". Well, if I remember right, the SCSI standard doesn't say what a drive has to do the the media for Format_Unit, and that the data in the sectors is not guaranteed to have any particular data in it (which of course means that the old data that was there is allowable). I suspect that if the quantum thought it had an unformatted disk (by whatever means) it would go out and write the sectoring information. In particular, Format_Unit does not guarantee a media check, even if it does go and format every track. You can supply bad block lists to Format_Unit if you know where they are (the normal default is to always map out the sectors the manufacturer marked as bad). We normally recommend you do a Verify (Verify Data on Drive in HDToolBox) on the drive and map out any bad or marginal sectors after a Format_Unit for safety. -- Randell Jesup, Keeper of AmigaDos, Commodore Engineering. {uunet|rutgers}!cbmvax!jesup, jesup@cbmvax.cbm.commodore.com BIX: rjesup Common phrase heard at Amiga Devcon '89: "It's in there!"
hargen@pdn.paradyne.com (Bill Hargen) (08/07/90)
In article <3757@tmiuv0.uucp> rick@tmiuv0.uucp writes: >Quantum drives don't actually do a low-level format. Essentially, they >recalibrate (reseek track 0) and report "Done". There are a few other >drives which do this. "SCSI is a standard that isn't". > >To my knowledge, the only way to low-level format a Quantum is to send it >back to Quantum. I have been working on writing a SCSI driver and the Prodrive 170S is one of the drives that I'm working with. I also noticed that the format command doesn't seem to do a real format (the heads jump around for about 5 seconds and then it claims it's done). The sales rep told me the same thing. Apparently Quantum believes that if a format is really necessary, then something is very wrong and the drive should be returned to the factory. However, try this: - issue the format command - before it has a chance to finish, PULL THE POWER (a SCSI bus reset may be sufficient, I just took the more direct approach :-) - now try another format I can't guarantee that this will cause it to do a real format, but it takes quite a bit longer and "sounds right". I too wish that drives weren't this "smart". Damn it, if I say format, I mean format! Hope this helps. -- Bill Hargen AT&T Paradyne {uunet,peora}!pdn!hargen Mail stop LG-132 Phone: (813) 530-8655 P.O. Box 2826 Largo, FL 34649-2826