Path: utzoo!attcan!utgpu!utstat!jarvis.csri.toronto.edu!mailrus!wuarchive!brutus.cs.uiuc.edu!rpi!crdgw1!crdos1!davidsen
From: davidsen@crdos1.crd.ge.COM (Wm E Davidsen Jr)
Newsgroups: comp.sys.ibm.pc
Subject: Re: RLL controllers with MFM drives
Message-ID: <1538@crdos1.crd.ge.COM>
Date: 3 Nov 89 15:23:32 GMT
References: <89102911043898@masnet.uucp> <1514@crdos1.crd.ge.COM> <1989Oct31.224410.272@rand.org>
Reply-To: davidsen@crdos1.UUCP (bill davidsen)
Organization: GE Corp R&D Center
Lines: 27

In article <1989Oct31.224410.272@rand.org>, edhall@rand.org (Ed Hall) writes:
|  
|  Now, I understand the difference between 1,3 RLL (aka MFM) and 2,7
|  RLL, and can see no reason why the latter would perform so poorly on
|  the ST-4096 unless Seagate either used exceptionally poor head
|  electronics (much worse than a MiniScribe drive a year older and three
|  times cheaper), or they intentionally engineered that electronics to
|  prohibit 2,7 RLL.

  I think the complete text of my posting included the word "most."
Since the drives sold for MFM are not tested for RLL timing accuracy,
you could get a unit which doesn't hack it. Remember that the TOTAL
timing jitter in drive, drive electronics, and controller is the
determining factor. You could have a controller which is in spec but not
better than spec.
|  
|  Perhaps I should post to alt.conspiracy.  I've certainly read of
|  ST-4096's running RLL.  I might just be unlucky.

  A lot of us have run 4096s and 251s RLL happily. I have done about six
of these installations, and I haven't had any trouble. The sixhub
archive server is running on one, and that has been very reliable.
-- 
bill davidsen	(davidsen@crdos1.crd.GE.COM -or- uunet!crdgw1!crdos1!davidsen)
"The world is filled with fools. They blindly follow their so-called
'reason' in the face of the church and common sense. Any fool can see
that the world is flat!" - anon