SCSI drive question: Do I need Wide?

SCSI drive question: Do I need Wide?

Post by Padmini Srinivas » Thu, 21 Sep 1995 04:00:00



Hello All,

I am considering purchasing a Pentium 120 Mz machine for text retrieval
research.  I would like to include an internal 9GB SCSI drive.  The
research is pretty disk intensive and thus I need a fast drive.  I have
read a number of messages posted on SCSI controllers but would still
like your opinions on the following issues:

1)  Does a wide controller (say AHA2940W) offer significant speed
improvements over a non-wide controller (say AHA2940)?

I think some one on this group recently suggested otherwise.  But I am
not sure I understood the argument provided.

2)  Is the 9GB size going to create any special iproblems during
Linux installation?

3)  Is there any problem about large capacity drives (internal) crashing
more frequently than external ones?

Thank you for your response.  I am trying to be as prepared as possible
for this purchase.

Padmini Srinivasan

 
 
 

SCSI drive question: Do I need Wide?

Post by Drew Eckhar » Sun, 24 Sep 1995 04:00:00




>1)  Does a wide controller (say AHA2940W) offer significant speed
>improvements over a non-wide controller (say AHA2940)?

Unless you have enough devices to have an aggregate head rate of
over 10M/sec (most modern high capacity SCSI disks peak at
5-6M/sec on the outer cylinders, although for twice the price of a
"normal" drive you can buy a parallel head 2G Baracuuda which does 14M/sec),
you won't see any performance difference between FAST and FAST+WIDE SCSI.

Not that I'd buy either Adaptec board; their technical support is
horrible.  Depending on what your parameters are, you can get a NCR board
for 1/4 the price with the same sort of stability and performance
(assuming you use the newer alpha drivers), or a Buslogic board for
about the same price that's extremely stable under Linux.

Quote:>2)  Is the 9GB size going to create any special iproblems during
>Linux installation?

Yes.  To access the last gigabyte, you need to not partition it (in
which case you can't boot the drive), or manually edit the partition
table (ie, with a binary editor) to set the 32 bit count field to extend
the final partition to the end of the disk.

Quote:>3)  Is there any problem about large capacity drives (internal) crashing
>more frequently than external ones?

It depends -

Big, fast drives draw a fair ammount of power, and generate a fair
ammount of heat.  If your case doesn't provide adequite ventilation,
an external will be more likely to work than an internal.

However, assuming that cooling is sufficient, you'll be less likely to
have cabling problems with internal drives, especially with the Adaptec
boards.

--
Everyone dies, but not everyone lives.  

 
 
 

SCSI drive question: Do I need Wide?

Post by Andries Brouw » Mon, 25 Sep 1995 04:00:00



>>2)  Is the 9GB size going to create any special iproblems during
>>Linux installation?
>Yes.  To access the last gigabyte, you need to not partition it (in
>which case you can't boot the drive), or manually edit the partition
>table (ie, with a binary editor) to set the 32 bit count field to extend
>the final partition to the end of the disk.

No, there is no problem whatsoever.
But you have to use fdisk 2.0e or fdisk 3.02.
All versions before 2.0e are not useable.
 
 
 

1. AIX 4.3.1, IBM 6208 Fast Wide SCSI, Seagate Ultra Wide 9.1 Gb drive?

Hello list!!

I am a technician for a company called Procom Technology.  We are resellers
of hardrives and I am having a tough time with a tricky AIX problem.  If

as I am not on the mailing list.  The situation I have is that a customer
has bought  a Seagate ST19171W from my company with the guarantee that it
would work in their system (described above).  From what I can tell over
the phone (ESP) is that the SCSI controller is configured correctly in the
system and is functioning correctly.  However, contrary to my experience
(with other OSes) AIX detecting the SCSI card does not impy that the
hardrive will be detected.  I need to find out if it is possible to
configure a non-IBM signature drive in AIX?  If it is, how is it done.  All
responses are appreciated.  Quick responses are highly appreciated (This
customer is flipping out!).

Many Thanks!

Keehan Mallon
Procom Tech Support

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