Subject: Re: Trouble with PCI, VGA, 32Mbyte
To: NetBSD-current Users <current-users@NetBSD.ORG>
From: Hellmuth Michaelis <>
List: current-users
Date: 06/11/1995 13:54:04
>From the keyboard of Peter Dufault:

> Thor Lancelot Simon writes:
> > The AWRE and ARRE bits in mode page 1 tell the *drive* to remap itself.  I
> > can't recall whether that implies doing so silently or not -- I think it does,
> > which is probably a good reason to do it in the driver instead, particularly
> > since in that case the user might have turned them off *so that* he can see the
> > errors.
> There is also the PER (post error) flag that tells the drive to be
> noisy.  However, there is still the issue of total read failures that
> the driver has to handle - the drive won't remap on read failure.
> My choices?  PER=1 AWRE=1 ARRE=1.

On ALL the *BSD SCSI drives i use i have AWRE and ARRE set to 1 but i think
this is not an optimal solution: you don't notice that your drives will fail
because you'll never see an indication that more and more sectors are silently
being remapped. When all spare sectors are used up, your drive will fail
completely from one second to the other.

What i prefer is, to set AWRE and ARRE to 0 so the errors get posted to the
driver, which in turn has to alarm (at least with a syslog entry) me that
a bad sector occured and who 1. tries to recover the data from the sector
in question (and also inform me about whether he was successful) and 2. does
the remapping of the sector to a good one.

Anyway, setting AWRE and ARRE and any other mode page values in scsi devices
must not be done by any driver.

Just my 0.02 ECU,
Hellmuth Michaelis        GFKT HCS Computertechnik GmbH        Hamburg, Europe
  Unplug cables at least semi-annually to allow unused bits to drain. (HP RAQ)