lkml.org 
[lkml]   [1996]   [Mar]   [28]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: SCSI bug

First off, sorry to redirect this to the list, but the original author
had sirdir@localhost.rutgers.edu, which of course maps out to 127.0.0.1
and won't work for mailing to him directly.

On Thu, 28 Mar 1996, Egbert Eich wrote:

> Andrew C. Esh writes:
> > sirdir wrote:
> > >
> > > Hi
> > > I encoutered a 'bug' in the SCSI subsystem of Linux. I have a harddrive
> > > that spins down now and then to do some sort of recalibration (silly
> > > thing, I know... but otherwise it's fast and big) .. And yes, if I say it
> > ...
>
> This discussion is on the wrong list. You should direct it to the SCSI list.
>
> > >
> > > anyways, i hope somebody can fix this problem... i love linux, but with
> > > this harddrive it's somewhat unusable...
> >
> > The drive is unreliable anyway. It's not the fault of the OS. If you
> > get it repaired, let me know what they did to it. I need to have mine
> > fixed too. (Is it possible you have the drive in power-saver mode?)
> >

In the past I have found two reasons other than drive manufacture that
can cause drives to spin down. You may want to check these out. The
first is the power supply. I had an SCO Unix box with a 2GB HP SCSI
drive in it. The drive would occasionally spin down for no good reason.
After putting a digital multimeter on the 12V line out of the power
supply and having it monitor with min and max saves on, I found that the
12V line would occasionally drop to as low as 10.5V. At 10.5V, the HP
drive would spin down but the controller board would still work.
However, since the controller didn't tell the spindle motor to spin down,
it was confused and would return a LONG string of drive read/write errors
and the machine would crash.

The second cause for this type of activity was one of the power
connectors for a cpu fan was plugged in between the power supply and the
drive. The connector (as many are) was unreliable any time you wiggled
the wires. The end result was, I took this connector and moved it
elsewhere and the drive quit spinning down.

>
> The drive is not broken. Some of the low-priced IBM-drives do this,
> they have to go into a maintenace mode every 72 hours to recalibrate, therfore
> they spin down completely for 1-2 minutes (I don't recall exactly).

However, if the drive in question isn't a low priced IBM, then it could
very well be broken, or it could be one of the two scenarios I mentioned
above.

> >
> > BTW: SCSI drives are *not* supposed to spin down by themselves without
> > being instructed to do so by the OS. This would be catastrophic.

They can spin down on there own, but it must be instructed to do so by
the controller on the drive or else it would also be confused and not
know what to do with requests, see above.

*****************************************************************************
* Doug Ledford * Unix, Novell, Dos, Windows 3.x, *
* dledford@dialnet.net 873-DIAL * WfW, Windows 95 & NT Technician *
* PPP access $14.95/month *****************************************
* Springfield, MO and surrounding * Usenet news, e-mail and shell account.*
* communities. Sign-up online at * Web page creation and hosting, other *
* 873-9000 V.34 * services available, call for info. *
*****************************************************************************



\
 
 \ /
  Last update: 2005-03-22 13:36    [W:0.049 / U:0.144 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site