Advice sought on Adaptec AHA 2940 UW & OS2

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3 total messages Started by Donald Wilson Fri, 16 Feb 1996 16:56

#55

Author: Donald Wilson
Date: Fri, 16 Feb 1996 16:56

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I am trying to decide whether to upgrade the memory on my system from 24mb's
to 32 or to upgrade from a SCSI 2 card and HD to SCSI 3 setup and would
appreciate any concrete information anyone can provide on which is the better
option.

I use OS2 on a 120mhz Pentium system (ASUS P55TP4XE board) with a 4MB Video
card and RAM as above and am looking to speed up disk I/O if I can. The SCSI
card I am considering is the adaptec AHA-2940 UW (or perhaps the AHA-2940W)
but I do not want to get this card and a new wide (or UW) SCSI drive and find
that the performance improvement is negligible. 

In particular, being largely ignorant of these things, I do not know whether
the faster transfer rates which SCSI 3 or U-SCSI offers are dependant upon the
drivers or only the firmware (and, if the drivers, whether the generic adaptec
driver provided with warp will support these faster transfer rates). I
currently have a Fujitsu 1.02 GB SCSI 2 drive with 512k cache and use an NCR
SCSI card (810 chipset) and, according to the "diskio" utility available on
Hobbes, the cache/bus transfer rate with this setup is 5063 k/sec. Since I
believe that transfer rates of up to 10mb/sec are supposed to be possible with
SCSI 2 and I clearly do not get this kind of rate with my current setup, I
thought I would check that purchasing the adaptec card would actually bring me
some benefit. I will settle for less that the 20mb/sec which fast wide SCSI is
supposed to support, but I do want to be sure that there will be an
appreciable improvement over my current setup to justify the cost here.

So, do the warp adaptec drivers support this card and the features it offers
and will I actually see something approaching the kind of transfer rates it
makes possible or am I wasting my money here (and would be better with the
memory). Also, I recall seeing a reference somewhere to a problem with some
ASUS boards and Adaptec SCSI cards, is there such a problem and is the board I
am using (P55TP4XE) amongst those affected? More generally, what kind of
features should I look for in a new HD? Is it important to go for one with a
greater onboard cache if I am using OS2? 

Thanks in advance for any help,

Donald Wilson.

Re: Advice sought on Adaptec AHA 2940 UW & OS2

#57

Author: Carl Albert Lindner
Date: Mon, 19 Feb 1996 01:18

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Donald Wilson (dywilson@scf.usc.edu) wrote:

: So, do the warp adaptec drivers support this card and the features it offers
: and will I actually see something approaching the kind of transfer rates it
: makes possible or am I wasting my money here (and would be better with the
: memory). Also, I recall seeing a reference somewhere to a problem with some
: ASUS boards and Adaptec SCSI cards, is there such a problem and is the board I
: am using (P55TP4XE) amongst those affected? More generally, what kind of
: features should I look for in a new HD? Is it important to go for one with a
: greater onboard cache if I am using OS2? 

I've just put together a machine a p-100 ASUS P55TP4XE with a 2940UW, 
mainly because the UW price wasn't much more then the wide 2940.  I've 
had no problems whatsoever.  I only have a 1 gig Seagate attached, the 
Hawk series I believe.  Warp Connect installed  without a 
hitch.  It picked up the controller without any problems.  Boot manager 
is installed with a 200 meg FAT and an 800 meg HPFS part.  If I 
understand things correctly, Computer Technology Review has said that 
SCSI-3 will run at about 100 mb/s and the Ultra is just a subset of 
SCSI-3.  I have yet to determine what the transfer rate really is....if 
you know of an easy way to find out let me know (email) and I'll give it 
a shot.  But I'm hedging a bet that I won't have to to really have more 
then the 10mb/s  and if the time is right then hopefully  40 mb/sec 
will be right around the corner....at least for a while....   

-------------------
Carl A. Lindner III
calindne@eos.ncsu.edu
Computer Science, North Carolina State University

Re: Advice sought on Adaptec AHA 2940 UW & OS2

#60

Author: Tom Maki
Date: Tue, 27 Feb 1996 20:16

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In <4g8j60$6vr@taco.cc.ncsu.edu>, calindne@eos.ncsu.edu (Carl Albert Lindner) writes:
        <...>
>SCSI-3.  I have yet to determine what the transfer rate really is....if 
>you know of an easy way to find out let me know (email) and I'll give it 
>a shot. 

Check out the OS/2 disk benchmarking utility "diskio"; you can find it on
  ftp://hobbes.nmsu.edu/os2/diskutil/diskio19.zip

As a point of reference, on my P120 with a NCR fast-wide controller, 
DEC DSP3210S, and Seagate ST32430W (both drives only 5400 rpm) I
get:

 Disk 1: 66 sides, 1009 cylinders, 63 sectors per track = 2048 MB
 Drive cache/bus transfer rate: 6802 k/sec
 Data transfer rate on track 0   : 4727 k/sec
 Data transfer rate on track 1008: 2300 k/sec
 Concurrent CPU activity and disk transfers: 19% CPU usage for disk I/O
 Average latency time: 1.0 ms
 Average data access time: 16.2 ms

 Disk 2: 66 sides, 1009 cylinders, 63 sectors per track = 2048 MB
 Drive cache/bus transfer rate: 2838 k/sec
 Data transfer rate on track 0   : 5672 k/sec
 Data transfer rate on track 1008: 3204 k/sec
 Concurrent CPU activity and disk transfers: 14% CPU usage for disk I/O
 Average latency time: 1.3 ms
 Average data access time: 16.3 ms

Cheers,
Tom

-Tom      maki@acm.org     http://www.umn.edu/nlhome/g561/maki0019
"a good picture may well be worth a thousand words, but on the WWW,
even bad imagemaps cost tens of thousands of words."

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