From: paulg@tplrd.tpl.oz.au (Paul Gittings)
Subject: Re: Help on CDC Wren hard drive.
Originator: paulg@sydrd19
Organization: Telectronics Pacing Systems
Date: Mon, 14 Dec 92 07:06:37 GMT


In article <1992Dec11.213719.9329@leela.cs.orst.edu>, ridgwad@atlantis.CS.ORST.EDU (Dean Ridgway) writes:
> Hello people, a friend of mine has several 5.25" format full-height CRC WREN
> 94171-344 300 meg hard drives and I am interested in buying one to put on my
> A500.  We don't have any documentation on these drives, no jumper settings etc.
> All we know is they were taken out of a SUN.
> 
[stuff deleted]
> 
> There are three different sets of jumpers.  Anyone have the jumper sheet for
> this?  Looking at the back of the drive...
> 
>                                  ;;;::   || PPPPP
> 
>  TTTTT   =============================   |: TTTTT
> 
>  = 50-pin SCSI connector
>  P power connector
>  T 16-pin DIP SCSI terminator pack
>  : jumper (open)
>  | jumper (closed)
>  ; These three jumpers are for the SCSI-ID
   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^  WRONG (at least in the 
   manual I have (Control Data Wren IV Disk Drive Model 95171 OEM manual).

There should be Two headers to the left of the power connecter
one with 5 Pairs of pins  one with two pairs of pins.

Going left to right across both sets of jumpers

            ABCDE FG

A - Jumper plug installed means parity checking  is enabled (Only select
    this if all other devices have parity checking enabled). On my
    A2000 with a GVP Series II controller my Wren does not have a jumper
    here.
B - Motor Start Option. When a jumper is here the drive will wait for
    a Start Unit command from the Host before starting the motor. If
    the jumper plug is not installed, the motor will start as soon
    as DC power is applied to the unit.  I don't have a jumper here

C,D,E - are the unit ID bits.
        No jumpers - 0
               E   - 1
              D    - 2
              DE   - 3
             C     - 4  etc.

F - Jumper to connect chassis ground - I have this jumpered.
G - Jumper to connect Signal ground - I have this jumpered.         


There is another jumper block below the power connector and to the left.
This is the Terminator Power source select jumper.
If the drive is not to be terminated this jumper needs not be installed
If you do have terminators on this drive you can install One jumper either 
horizontally or vertically.
Vertically 
          |:
Means terminator power is taken from the Power connector (this is what I
have and looks like it is what you have).
Horizontally
          ..
          __

Takes the power from the interface cable.

I have a Wren IV in a PC box connected to a GVP controller and I have been 
using it for a week now without any of the problems you described.

Cheers,
Paul Gittings
Telectronics Pacing Systems- 7 Sirius Rd, Lane Cove, NSW 2066, Australia
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