[comp.unix.i386] CDC WREN IV is Lying!!!

apb@lzga.ATT.COM (Amrit Bains) (08/10/90)

Hi,

I just brought a CDC WREN IV Model Number 94171-307  ( 8-).
The disk drive has 320 MB of disk space.

But when I added it to my system it showed only 286 MB  ( 8-( ).
Does anyony know why this is happening!!!

My Configuration:

386/25 C&T Motherboard.
CDC WREN IV 320MB (shows only 286 MB)- (BOOT DISK SCSI ID 0)
80MB Seagate ST296N - (SECOND DISK SCSI ID 1)
WD7000-FASST2 SCSI Host Adapter.  (Western Digital)

Any help would be appreciated!!!!

apb@lzga.att.com
or
abains@attunix.att.com

herbie@bruce.cs.monash.OZ.AU (Andrew Herbert) (08/13/90)

In <2001@lzga.ATT.COM> apb@lzga.ATT.COM (Amrit Bains) writes:
>I just brought a CDC WREN IV Model Number 94171-307  ( 8-).

Me too ;-).

>The disk drive has 320 MB of disk space.
>But when I added it to my system it showed only 286 MB  ( 8-( ).
>Does anyony know why this is happening!!!

Well... According to the OEM manual, the -307 means it comes formatted for
307MB.  A table in the abovementioned indicates that if formatted with 512 byte
sectors and no spare sectors on each track the drive will end up with 307MB.
To get 320MB, format with 1024 byte sectors and no spares.  From memory, having
one spare 512 byte sector per track (or perhaps they meant cylinder?) results in
a 301MB drive.

Andrew

p.s. Anyone know how to select what read-ahead the drive uses with its cache?
Also, what is the performance difference between the -307 Wren IV and the
-344?  (i.e. how much difference does synchronous scsi make?)  Thanks.

jbayer@ispi.COM (Jonathan Bayer) (08/13/90)

apb@lzga.ATT.COM (Amrit Bains) writes:


>Hi,

>I just brought a CDC WREN IV Model Number 94171-307  ( 8-).
>The disk drive has 320 MB of disk space.

This is unformatted capacity!!!!


>But when I added it to my system it showed only 286 MB  ( 8-( ).
>Does anyony know why this is happening!!!


This is after being formatted!!!



JB
-- 
Jonathan Bayer		Intelligent Software Products, Inc.
(201) 245-5922		500 Oakwood Ave.
jbayer@ispi.COM		Roselle Park, NJ   07204    

akcs.gregc@ddsw1.MCS.COM (*Greg*) (08/14/90)

Probably the manufacturer programmed it to do that for obvious reasons.

- Greg

dolf@fwi.uva.nl (Dolf Starreveld) (08/14/90)

apb@lzga.ATT.COM (Amrit Bains) writes:
>Hi,

>I just brought a CDC WREN IV Model Number 94171-307  ( 8-).
>The disk drive has 320 MB of disk space.

>But when I added it to my system it showed only 286 MB  ( 8-( ).
>Does anyony know why this is happening!!!
CDC always lists its products with unformatted capacities. The product
number you give indicates that it is a 307 Mb unformatted disk. On the other
hand and add I have here advertises the Wren IV as 350M unformatted.
I do not have my CDC documentation handy here, so I can not tell you which
of the two is right. 
Anyway, if the unformatted capacity is 307 or 320 (the number you mention)
286M formatted is quite normal.

>My Configuration:

>386/25 C&T Motherboard.
>CDC WREN IV 320MB (shows only 286 MB)- (BOOT DISK SCSI ID 0)
>80MB Seagate ST296N - (SECOND DISK SCSI ID 1)
                 ^^ Here is another example. 96Mb unformatted, 80Mb formatted.
>WD7000-FASST2 SCSI Host Adapter.  (Western Digital)


--dolf
--
Dolf Starreveld  Phone: +31 20 592 5056/5022 (FAX: 5155), TELEX: 10262 HEF NL
EMAIL:           dolf@fwi.uva.nl (dolf%fwi.uva.nl@hp4nl.nluug.nl)
SNAIL:           Dept. of Math. and Computing Science, University of Amsterdam,
                 Kruislaan 409, NL-1098 SJ  Amsterdam, The Netherlands

heiser@tdw201.ed.ray.com (08/14/90)

In article <2857@bruce.cs.monash.OZ.AU> herbie@bruce.cs.monash.OZ.AU (Andrew Herbert) writes:
>In <2001@lzga.ATT.COM> apb@lzga.ATT.COM (Amrit Bains) writes:
>>I just brought a CDC WREN IV Model Number 94171-307  ( 8-).
>
>Me too ;-).
>
>>The disk drive has 320 MB of disk space.
>>But when I added it to my system it showed only 286 MB  ( 8-( ).
>>Does anyony know why this is happening!!!
>
>Well... According to the OEM manual, the -307 means it comes formatted for
>307MB.  A table in the abovementioned indicates that if formatted with 512 byte
>sectors and no spare sectors on each track the drive will end up with 307MB.
>To get 320MB, format with 1024 byte sectors and no spares.  From memory, having
>one spare 512 byte sector per track (or perhaps they meant cylinder?) results in
>a 301MB drive.

How does one change this so as to use the "full capacity" of the drive?
Why is it set up this way (what is the technical reason for it)?

Thanks,
Bill

-- 
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	Other:	heiser@world.std.com     (Public Access Unix)

ecr@cipric.mn.org (Edward C. Regal) (08/16/90)

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

src@scuzzy.mbx.sub.org (Heiko Blume) (08/23/90)

heiser@tdw201.ed.ray.com writes:
>>[using]
>>one spare 512 byte sector per track (or perhaps they meant cylinder?) results
>>in a 301MB drive.

>How does one change this so as to use the "full capacity" of the drive?
>Why is it set up this way (what is the technical reason for it)?

you have to talk to the disk using a utility like 'scsicntl.exe' from roy neese
(he's at adaptec and the utility only works with adaptec host adapters)
to issue the proper mode select commands to the drive. you can set a lot
of very interesting parameters that can affect throughput dramatically.
especially read-ahead buffers and caches are *disabled* by default in many
drives.
i have posted a long description of many of these parameters (for disk drives)
to comp.periphs.scsi some weeks ago.
i also have the above mentioned software, but i'm in germany so you'd better
look elsewhere first.

-- 
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