Path: utzoo!attcan!uunet!olivea!decwrl!shelby!msi.umn.edu!cs.umn.edu!atc!cimcor!mike
From: mike@cimcor.mn.org (Michael Grenier)
Newsgroups: comp.periphs.scsi
Subject: Re: ST02 - doesn't work with ProDrive Quantum S80 - Why ?
Message-ID: <1991Jan28.025339.9730@cimcor.mn.org>
Date: 28 Jan 91 02:53:39 GMT
References: <1991Jan27.042046.10471@watserv1.waterloo.edu>
Organization: Scandia Microsystems
Lines: 57

(The Sanj-Machine aka Ice):
> In article <1991Jan18.003222.15824@smsc.sony.com> tin@smsc.sony.com (Tin "Man" Le) writes:
>>
>>  I have personally used (am using) several different non-Seagate SCSI
>>  drive with an ST02.
>>
> 
> Chances are, you are not getting the performance you could be getting.
> To paraphrase from comments last year on the ST-02. It is "an obsolete
> Future Domain design that Seagate bought the rights to, and now bundle
> with their systems." "It is dirt cheap." It is an 8-bit controller with
> NO support from Unix vendors. It is okay if you intend to only run DOS/Windows.
> 
> But if you have high performance SCSI drives, look elsewhere. Only a 


I couldn't let that pass!

The ST-02 controller may be cheap but its not that bad...certainly
better than ESDI and RLL. 

There is a PD UNIX driver for the board which works fine. Using the
raw device and big blocks a friend with a 25MhZ board can transfer
at rates around 1.2 Megabytes per second to a Wren IV using
    dd if=/dev/rscsi0s0 of=/dev/null bs=100k count=...

which is much faster than many get with the Adaptec 1542. 

I realize that vendor support is nice and thus I would recommend
a supported card particularly if it is the only controller card
you will use. The ST-01 is a nice choice though if you are going
to boot a MFM/RLL/ESDI drive.

Remember a few points :
    SCSI (for almost all drives) is an 8 bit protocol. So 16 bit
   boards may not buy you that much.

    The AT bus even in 8 bit mode is as fast as most scsi drives
   in async mode.

    The ST-01/02 controllers controller the wait line on the bus
    to sync the transfer from the card to memory - relieving the 
    need for the software driver to poll the card to see if more
    date is ready...this also speeds up transfers. In fact,
    because you can use the REP memory move instructions, transfers
    move as fast 8-bit DMA.

    Cards like the Adaptec 1542 do not run in all motherboards
    (including the one I'm typing this message in at!).

I'm not saying that a $25 card like the ST-01 is better than
anything on the market and I certainly would not want to compare
it one on one with cards like the Adaptec with is fast bus mastering.
I'm just saying that it not as bad as many believe.

    -Mike Grenier
    mike@cimcor.mn.org