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From: roy@cs.fau.edu (Roy Levow)
Newsgroups: comp.periphs.scsi,comp.sys.ibm.pc.hardware
Subject: Re: How much faster is a 16 bit SCSI Card than the ST02?
Message-ID: <1991May31.170158.29687@cs.fau.edu>
Date: 31 May 91 17:01:58 GMT
References: <396@oiscola.Columbia.NCR.COM>
Organization: Florida Atlantic University, Boca Raton
Lines: 47

In article <396@oiscola.Columbia.NCR.COM> dmoyer@oiscola.Columbia.NCR.COM (Dan Moyer) writes:
>I currently have a 386sx with a Seagate ST-02 and ST296N SCSI disk.
>
>With CORETEST and with Nortons SI benchmark, I get a reading of about
>220-300 K bytes/sec transfer time, and a 28-31 ms access time.
>  ... 
>I am considering purchase of a 16 bit board.
> 
>I currently operate DOS and sometimes Windows 3.0 now.   Sometime
>in the future (6-12 months), I'd like to be able to use OS/2 2.0 or
>Unix.  
> 
>1)  What performance increase can I expect with a adapter card
>    like the IN2000 or ADAPTEC 1542B, using the same ST296N disk.
>    (I assume I'll need to do a low level format to get 1:1
>     interleave).   If anyone outhere has done gone from a 8 bit
>     card to a controller card like IN2000, WDFAST, or ADAPTEC, 
>     how much better has your disk performance become?  I'd like to get
>     an idea of this, before I purchase a new adapter card.
> 
>2)  Does anyone have recommendations of what board works, (or which
>    ones don't work) with the ST296N disk?
>  ...
>5)  In planning to goto OS/2 2.0 or Unix in the future, what should
>    I avoid purchasing?   Should I change my idea of getting a SCSI
>    adapter alltogether, and just get a faster IDE or ESDI drive, and
>    keep the old card?

I recently replaced an ST02 on my 20MHz 386 with an Always IN-2000.  I
have a pair of ST296N's on the system.  Before upgrading, my trasnfer
rate was about 400+ KBps.  After the upgrade, with the same 2:1
interleave, there was no change in transfer rate.  But when I did the
low-level reformat to 1:1, the transfer rate doubled.  As an added
benefit, my floppy access time improved significantly.  (I didn't time
it before, so I can't quantify the increase, but it is quite
noticeable.)  By the way, the LL reformat was necessary to boot from
the hard disk with the new card even though I could access the disks
without it.

It is my understanding that the AHA-1542 would be a better choice for
a Unix system because of its DMA support; rather than the dual-port
RAM used on the IN-2000.  Someone else out in netland can probably
give you more details on this.  You also want to be _very_ careful
that the specific system you are planning to upgrade to supports the
controller you have purchased.  Since I have no plans to change from
the DOS/DESQview combo I am currently using, I didn't think it was
worth the extra $100 for the Adaptec card.