Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!sun-barr!olivea!uunet!sjsca4!poffen
From: poffen@sj.ate.slb.com (Russ Poffenberger)
Newsgroups: comp.sys.ibm.pc.hardware
Subject: Re: SCSI & RLL:  compatible?
Message-ID: <1991Feb28.211256.17985@sj.ate.slb.com>
Date: 28 Feb 91 21:12:56 GMT
References: <7yy0w2w163w@brainiac.raidernet.com> <26907@uflorida.cis.ufl.EDU> <1420@lehi3b15.csee.Lehigh.EDU>
Reply-To: poffen@SunOS (Russ Poffenberger)
Organization: Schlumberger Technologies, ATE division, San Jose, Ca.
Lines: 42

In article <1420@lehi3b15.csee.Lehigh.EDU> kdunn@lehi3b15.csee.Lehigh.EDU (Kevin Dunn) writes:
>>In article <7yy0w2w163w@brainiac.raidernet.com> sophist@brainiac.raidernet.com (Phillip McReynolds) writes:
>>>Is it possible to have both an RLL drive+controller & a SCSI
>>>drive+controller inhabiting the same machine?  If it *is* possible, are
>>>there any problems which might make such a scheme either troublesome or
>>>unreliable?
>
>    I would advise against it.  I just spent the last month in that situation.
>  I was running a 65meg RLL drive.  (The drive is actually a 42meg Miniscribe
>3650 MFM that was formatted RLL by the company I bought the computer from.
>  Cheapwads!)
>    Anyway, I bought an 85meg SCSI (ST 296, I think) and an ST01 controller.
>  About half of the time, both worked. The other half of the time, one or
>both of the drives wouldn't work AT ALL.  It was completely random.  A disk
>crash made me do a low-level format on the 65meg RLL, and from then on it
>would only Low level format to 42 megs, no matter what I tried.  Also,
>strangely enough,  about 45% of the time, the drive would not boot (I tried
>both the SCSI and RLL as boot drives) from a coldboot:  A warm boot, however,
>worked fine!  Weird!
>    I tested each drive alone in the computer, and both worked 100% correctly.
>  Something in the interaction was fouling things up, but, like I said, only
>randomly.
>     This has been my experience with a SCSI/RLL duo.  I hope you have better
>luck.  I too, before I started, was assure by Segate and Miniscribe and various
>dealers that there would be no problem....


It would probably work better with a REAL SCSI controller. The ST01 isn't a
real controller, just a brain-dead adapter.

I have successfully run ST506 type drives (MFM,RLL) with my Adaptec AHA1542B
controller (REAL controller) with no problems. Note that because of the AT
BIOS spec., the ST506 type drive becomes the primary bootable drive. You can't
boot off the SCSI, but it is recognized during bootup and is available to
DOS.

I don't do this anymore because my 327Mb Wren IV is plenty.

Russ Poffenberger               DOMAIN: poffen@sj.ate.slb.com
Schlumberger Technologies       UUCP:   {uunet,decwrl,amdahl}!sjsca4!poffen
1601 Technology Drive		CIS:	72401,276
San Jose, Ca. 95110             (408)437-5254