Xref: utzoo comp.sys.ibm.pc:15620 comp.sys.misc:1430
Path: utzoo!attcan!uunet!husc6!think!bloom-beacon!mit-eddie!uw-beaver!cornell!rochester!udel!princeton!mccc!pjh
From: pjh@mccc.UUCP (Pete Holsberg)
Newsgroups: comp.sys.ibm.pc,comp.sys.misc
Subject: Re: RLL Technical Details (long) (was Re: RLL- why it is hard on drives)
Message-ID: <661@mccc.UUCP>
Date: 16 May 88 19:58:28 GMT
References: <1255@kodak.UUCP> <638@mccc.UUCP> <216@octopus.UUCP> <650@mccc.UUCP> <218@octopus.UUCP>
Reply-To: pjh@mccc.UUCP (Pete Holsberg)
Organization: The College On The Other Side of Route 1
Lines: 34

In article <218@octopus.UUCP> pete@octopus.UUCP (Pete Holzmann) writes:
...If you read all the way through this, you will (hopefully) understand WHY
...RLL works/doesn't work depending on the configuration you set up. You will
...also understand WHY many of the horror stories applied to RLL are almost
...certainly mis-applied.
...
...In article <650@mccc.UUCP> pjh@mccc.UUCP (Pete Holsberg) writes:
...I don't mean to call you a liar. Misled, yes. That isn't your fault! This
...article is an attempt to correct the problem...

Misled?  You think that the guys who told me that they were unable to
MFM-format a plated media drive that they had run under RLL were
kidding?  Frankly, I didn't initially believe them either, but enough of
them said the same thing that I got rid of my ST-225 asap.  Maybe it's
another hummingbird case: theoretically, there's nothing that an RLL
controller can do to prevent a disk from being reformatted, but in these
cited cases, it happened.  Probably in conjunction with a powersupply
problem or some such thing, eh?

...I. How is data stored on a disk drive?
...
...As magnetic flux reversals (think of it as + to -). The POLARITY of the
...magnetic flux doesn't mean a thing. It is the TIMING of the flux reversals
...that is used to encode data.

Don't the - to + reversals count?  The d(phi)/dt exists!  By timing, do
you mean the magnitude of the d(phi)/dt or what?

...P.S.: If you read all the way to here, congratulations! I don't really expect
...that this stuff would really be interesting enough for people to read through
...250 lines of gobbledy gook... :-)

Thanks for the "gobbledygook"!  I'll have to read it at my leisure to
see if it makes any sense to me.