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From: honeywel@hydra.unm.edu (Michael A. Thomas - Honeyw)
Newsgroups: comp.periphs.scsi
Subject: Re: CDC WREN IV is Lying!!!
Keywords: scsi, wren
Message-ID: <1990Aug20.171219.26153@ariel.unm.edu>
Date: 20 Aug 90 17:12:19 GMT
References: <2001@lzga.ATT.COM> <353@cipric.mn.org> <1990Aug20.115516.1454@granite.cr.bull.com>
Sender: usenet@ariel.unm.edu (USENET News System)
Organization: University of New Mexico, Albuquerque
Lines: 36

In article <1990Aug20.115516.1454@granite.cr.bull.com> moncreaf@granite.cr.bull.com (Donald W. Moncreaff) writes:
>In article <353@cipric.mn.org> ecr@cipric.mn.org (Edward C. Regal) writes:
>>In article <2001@lzga.ATT.COM> apb@lzga.ATT.COM (Amrit Bains) writes:
>>>I just brought a CDC WREN IV Model Number 94171-307  ( 8-).
>>>The disk drive has 320 MB of disk space.
>>>when I added it to my system it showed only 286 MB  ( 8-( ).
>>
>>Sounds like the old lying drive trick to me ...(:-
>>
>>Actually sounds like the difference between an unformatted and a 
>>formatted drive.
>>
>>Ed
>
>what is the range of formatted capacity for the wren *-307 drives?



   Regarding formatted capacity versus unformatted, I came across something
that might be interesting in the CDC manuals:

   WREN IV SCSI MODEL 94171-344

   Formatted capacity achieved depends on the number of spare reallocation
   sectors reserved and the number of bytes per sector.  The following table
   shows some typical formatted capacities achievable.

   Spare sectors or cylinders                 Sector Size 
   reserved for reallocation         512 Bytes/Sect.|1024 Bytes/Sect. 
   ---------------------------------------------------------------

   No spares                         330MB                 345MB
   One spare sector per track        323MB                 330MB
   Two spare cylinders/unit*         330MB                 344MB
 
  *Spare cylinders are on the inner tracks.