Xref: utzoo comp.sys.amiga.hardware:2832 comp.periphs.scsi:827
Path: utzoo!utgpu!news-server.csri.toronto.edu!rutgers!bpa!cbmvax!jesup
From: jesup@cbmvax.commodore.com (Randell Jesup)
Newsgroups: comp.sys.amiga.hardware,comp.periphs.scsi
Subject: Re: NEED MORE HELP!! (formatting Quantum ProDrive)
Message-ID: <13531@cbmvax.commodore.com>
Date: 31 Jul 90 03:03:52 GMT
References: <1990Jul25.190605.11054@msuinfo.cl.msu.edu> <3757@tmiuv0.uucp>
Reply-To: jesup@cbmvax (Randell Jesup)
Distribution: usa
Organization: Commodore, West Chester, PA
Lines: 31

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!"