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From: sansom@trwrb.UUCP (Richard Sansom)
Newsgroups: comp.sys.atari.st
Subject: Re: Twister, Format+
Message-ID: <1902@trwrb.UUCP>
Date: Mon, 18-May-87 11:29:07 EDT
Article-I.D.: trwrb.1902
Posted: Mon May 18 11:29:07 1987
Date-Received: Tue, 19-May-87 04:13:11 EDT
References: <8705081618.AA15013@ucbvax.Berkeley.EDU> <13104@watmath.UUCP> <967@batcomputer.tn.cornell.edu> <719@ttidca.TTI.COM>
Reply-To: sansom@trwrb.UUCP (Richard Sansom)
Distribution: world
Organization: TRW EDS, Redondo Beach, CA
Lines: 32

In article <719@ttidca.TTI.COM> woodside@ttidcb.UUCP (George Woodside) writes:
>TWISTER compensates for the track step/head settle/position verify
>time by staggering the sectors on the tracks in relation to the index mark,
>like this:
>
>  INDEX---+  Sectors
>(TRK 00)  !  1  2  3  4  5  6  7  8  9  10
>(TRK 01)  !  3  4  5  6  7  8  9 10  1  2
>(TRK 02)  !  5  6  7  8  9 10  1  2  3  4

I think that twisting is backwards - shouldn't it be:

    (TRK 00)  ! 1  2  3  4  5  6  7  8  9  10
    (TRK 01)  ! 9 10  1  2  3  4  5  6  7  8
    (TRK 02)  ! 7  8  9 10  1  2  3  4  5  6

otherwise, you'll have to wait for 7-8 sectors to pass before sector 1 comes
around again.  Also, if you look at the original code (file mmtwst.c, I think)
you'll see that is the way Twister actually does it.

I modified Twister to allow user spcification of sectors per track and
tracks per side.  I was hoping to get Atari's permission to post using the
(Atari copyrighted) FDC code which was published with Twister, but,
unfortunately, never got a reply (and I'm too lazy to completely rewrite the
code).

-Rich
-- 
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  /// Richard E. Sansom                   TRW Electronics & Defense Sector \\\
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