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From: saj@chinet.chi.il.us (Stephen Jacobs)
Newsgroups: comp.sys.atari.st
Subject: Re: HELP IDENTIFYING SEAGATE 296N WITH REV. 7 ROM
Summary: Let's play Humpty Dumpty with words
Message-ID: <9355@chinet.chi.il.us>
Date: 25 Aug 89 14:05:27 GMT
References: <2520@orion.cf.uci.edu> <5440048@hplsla.HP.COM>
Organization: Chinet - Chicago, Ill.
Lines: 31

In article <5440048@hplsla.HP.COM>, andyc@hplsla.HP.COM (Andy Cassino) writes:
(Replying to the statement: )
> | 
> |      My only comment about the Seagate 296N is that it was supposed to
> |      be a 1:1 interleave drive, and people paid money for that spec.
> |      As far as I know, Seagate has yet to deal fairly  with its customers
> |      who purchased the ROM8 version of the 296N.
> | 
> 
> Well, the ROM 8 does format 1:1, and an ST can read it, though it's doggo-slow. 
> The optimum interleave for any computer/controller/disc combination is 
> not always 1:1!

This is true, but cheating on meanings.  When one says that a disk with 
built-in controller can be formatted for 1:1 interleave, the normal expectation
is that this means the controller will be able to deliver consecutive sectors
to a DMA device without read errors.  In other words, you can read a whole
track in one revolution if your computer is fast enough.  The ST 296N can't
do this (Rev 8 ROM).  It has nothing to do with the computer.  The optimum
interleave for a single magnetic disk on a system is the tightest interleave
that doesn't give frequent failures (for small interleave ratios, at least:
note that I said for a single disk).  The ST 296N gives something like 50%
failures when you try to read consecutive sectors consecutively, and a few
failures when you try to read alternate sectors consecutively (2:1 interleave)
Given the ordinary usages of words, that means it doesn't support 1:1
interleave.
   All this is against the background that I have an ST 296N (formatted for
2:1 interleave), I like it very much, I recommend it as about the best buy
around in disk drives and I rescued a friend who was mad at his ST 296N (on
a PC compatible) with 1:1 interleave (he finds 3:1 better than 2:1).
                              Steve J.