Re: Low-level format with Sg drivers
Susan E. Wiig (susan@dit.com)
Tue, 13 Apr 1999 07:57:46 -0600
Douglas Gilbert wrote:
>
> Susan E. Wiig wrote:
> >
> > Has anyone out there ever done a low level format using the generic scsi
> > drivers. Why I ask is when I do it the write sends out the command to
> > the drive, a Zip drive in this case, and the drive goes off and happily
> > starts to do the low level format but it comes back too soon. It then
> > does the read but there is a sense error. The sense error I get is
> > Medium Error, Not ready to ready transition ( medium may have
> > changed). I know the commands I send to the drive are correct, in fact
> > I have looked them up in the Zip specs.
> >
> > Could there be some type of signal that is causing the low-level
> > formatting to be ending to soon, or is there some signal I should send
> > between the write and the read in the scsi call?
> >
> > I am at a loss.
>
> Susan,
> I have not tried a low level format (by which I assume you mean the
> SCSI command FORMAT UNIT). One thing to look out for would be the
> default 60 second timeout. From your error message from the sense
> buffer that doesn't seem to be your problem. Typically the SCSI
> command you execute after closing the door on the removable media
> will get the "not ready to ready transition" error. The usual
> response is to try it again. But if this was the case it should be
> reported pretty well immediately.
>
> If there is a timeout after 60 seconds then I would expect the
> 'host_status' to be set to DID_TIME_OUT (0x03). Could it be
> possible a timeout occurred and the sense_buffer already had
> that data in it from an earlier command?
>
> The default timeout can be elongated by the SG_SET_TIMEOUT
> ioctl.
>
> Doug Gilbert
Doug
Actually when I checked again the sense buffer from the read right after
the low-level format quit was Unit Attention, Data Path Failure
(Should use 40 NN). I haven't figured out what 40 NN is yet. I guess
this message may not be surprising since I just did a low level format
on the disk. Maybe things get lost between the write and the read.
Your idea about the timeout is worth a try. I am also going to try an
ioctl call to the sd* driver and see if that works.
Let you know what happens.
Susan
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