Summary: disk questions

From: David LeVine (levine@berlioz.nsc.com)
Date: Wed Jul 31 1991 - 06:43:36 CDT


This is my original query:

> Has anyone attached either a Fujitsu M2382K or a CDC 9720-1320 (1230MB)
> drive to a Sun 7053 controller? If so, what format.dat entries did you
> use? Were there any problems, in particular any data corruption or timing
> problems? This has suddenly become a hot issue so any help is appreciated.
> Please send responses directly to me as I am not on this mailing list. I
> will summarize if there is interest. Thanks in advance.

First of all, there was a typographical error in my original request in that
I specified 'CDC 9720-1320' instead of 'CDC 9720-1230'.

I received responses from:

        dan@breeze.bellcore.com (Daniel Strick)
        Jeff Nieusma <nieusma@cs.Colorado.EDU>
        bb@math.ufl.edu
        markw@utig.ig.utexas.edu (Mark Wiederspahn)
        dmorse@sun-valley.Stanford.EDU (Dennis Morse)
        tsacas@ilog.ilog.fr (Stephane Tsacas)
        perw@holtec.se (Per Westerlund)
        sylvman!ed@uunet.UU.NET (Ed Haggerty)
        mesaint@pacific.mitre.org
        Ken Nawyn <ken@nynexst.com>
        apple!nli.com!stan@nsc.nsc.com (Stan Sawyer)
        jrich@ucrmath.ucr.edu (john richardson)
        John Valdes <valdes@geosun.uchicago.edu>
        ssi!ssiwest!spott@uunet.UU.NET (Dave Spott)
        Mike Raffety <miker@sbcoc.com>
        sitongia@hao.ucar.edu (HAO Computer System Managment Group)
        Dan Williams <dan%ufnmr.uucp@eecs.nwu.edu>

Most responses contained useful information and some were even consistent
with others. After reviewing them and verifying hardware switch settings
I came up with these two format.dat entries:

> disk_type = "Fujitsu-M2382K" \
> : ctlr = XD7053 \
> : ncyl = 743 : acyl = 2 : pcyl = 745 : nhead = 27 : nsect = 83 \
> : rpm = 3600 : bpt = 49728 : bps = 592
>
> disk_type = "CDC 9720-1230" \
> : ctlr = "XD7053" \
> : ncyl = 1631 : acyl = 2 : pcyl = 1633 : nhead = 15 : nsect = 83 \
> : rpm = 3600 : bpt = 50400 : bps = 600

These parameters yielded capacities of 782506MB and 954079MB, respectively,
on a 4/380 running 4.1.1. This system has six of the CDCs and two of the
Fujis, with the OS installed on one of the CDCs.

There was some strangeness. When restoring the system disk, I received
a couple of errors of the form:

> xd0a write restore (drive not on cylinder) blk# 64 abs blk# 64

The data seems to have been restored successfully and the system boots
fine.

During the verify portion of the formatting process of the other disks, I
saw two types of error messages several times:

> Block 702723 (313/15/45), Corrected media error (soft ecc corrected)
> Repairing...succeeded.
 
> Block 880378 (392/22/80), Fatal media error (header not found)
> Repairing...succeeded.

The 'header not found' is bothersome, however, since the second pass of
the verify was clean, I'm not pursuing it further. These messages only
seemed to appear in larger than expected numbers while I was formatting/
verifying multiple disks in parallel. I didn't see them (especially the
'header not found' message) when I did only one disk at a time. I guess
it's possible that too many formats could cause confusion (???). If anyone
has any comments or thinks this is a disaster waiting to happen please mail
your thoughts to me.

If anyone want's a copy of all the responses, please send me mail. Thanks
again to all who responded.

        David LeVine
        levine@berlioz.nsc.com
        408-721-5317



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