Formatting a Wren VII (summary)

From: Chris Franz (franz@asuvax.eas.asu.edu)
Date: Tue May 08 1990 - 16:06:50 CDT


A few weeks ago I asked for help formatting a Wren VII. If you think
that there is even a slight possibility of getting one of these hummers
in your shop, I would suggest that you save this summary; it will save
you a lot of time watching a disk format.

Original Post:

> Has anyone had success formatting a Wren VII (1.2 GB)
> connected to a SS1 running 4.0.3c MUNIX? If so, please
> contact me via email.

There were two problems with the format process. 1) I didn't know
what parameters to use and 2) when I did come up with some, the
format would not run to completion (or so it seemed).

Problem 1) Solution:

>From Guy Turcotte, turcotte@asterix.drev.dnd.ca

> Here are the parameters that we used to format our CDC Wren VII. Those
> info come from the format.dat file of SunOS 4.1 beta:
>
> disk_type = "CDC Wren VII 94601-12G" \
> : ctlr = MD21 : fmt_time = 4 \
> : cache = 0x11 : trks_zone = 15 : asect = 5 : atrks = 30 \
> : ncyl = 1703 : acyl = 2 : pcyl = 1931 : nhead = 15 : nsect = 80 \
> : rpm = 3600 : bpt = 31410
>

and, from Bob Kusumoto, kusumoto@chsun1.uchicago.edu

> I used the following driver:
>
> disk_type = "CDC Wren VII 94601-12G" \
> : ctlr = MD21 : cache = 0x11 \
> : ncyl = 1925 : acyl = 2 : pcyl = 1931 : nhead = 15 : nsect = 70 \
> : rpm = 3600 : bpt = 41301
>
> since the format command didn't work, I left the the parameter for
> fmt_time. Using this driver, I came up with 2021250 0.5K blocks. the
> ncyl was suppose to be 6 less than pcyl, 2 for acyl and 4 for the MD21
> controller, so there's little incentive to increase ncyl. You can try
> increasing the nsect parameter (up to roughly 80) to get a little more
> out, but I took a safe route. Don't worry about the partition info, you
> can enter it in the partition menu and its more malliable that way.
> Partition c should be set to 0 and 1925/0/0.

I used the latter because some documentation accompanying the disk stated
that it should be 1.035 GB formatted (1925*15*70*512 = 1.035 GB).

Problem 2) Solution:

>From Doug Neuhauser, doug@seismo.gps.caltech.edu and
     Per Westerlund, perw@holtec.se

(Doug)
>> A few weeks ago I posted a request for information on formatting a Wren 7
>> 1.2 GB disk drive on either a 4/280 or SS1. The vender that was supplying my
>> drives finally admitted that they couldn't format on either machine due to
>> a "timeout".
        .
        .
        .
(Per)
> I just wanted to add that it is possible to format a drive even you have
> the timeout problem, I have done it myself. Remember that the timeout
> problem is a problem in the driver, the disk formats as it should.
>
> Run it this way:
>
> Run format, and start the formatting.
>
> After a while there is a message about a timeout, and that
> the format failed. Don't touch anything, just wait!
>
> After a while more, there is a message about an unsolicited
> reconnnect or something like it. That is the drive trying to
> say that the format is finished. (I am assuming that nothing
> strange is happening during the format. Most errors are
> parameter errors and those are usually caught immediately.)
>
> Now, the drive is formatted. Proceed as usual with analysing,
> labelling etc.
>
>

This is exactly what happened in my case and, indeed, the disk seems
to be formatted correctly.

Thanks to Guy, Bob, Doug, Per, and others who sent information.

Chris
franz@asuvax.eas.asu.edu



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