Re: Track/sector staggering

[christer@cs.umu.se (Christer Ericson)]

In <2upmja$189@mojo.eng.umd.edu> russotto@eng.umd.edu (Matthew T. Russotto) writes:

>In article <mobrienCrny8w.2tD@netcom.com> mobrien@netcom.com (Michael O'Brien) writes:
>}mnementh@netcom.com (David R. Villegas) writes:
>}> The physical sector order on each track is 0 7 E 6 D 5 C 4 B 3 A 2 9 1 
>}8 F.
>}
>}Thanks for replying.  However, that's not exactly what I'm talking about.
>}Let me rephrase my question: if I read sector 0 and then immediately seek
>}to the next track, what will be the next sector under the read head?  I bet
>}it's not 7.

>"Undefined".  Only copy-protection schemes made an attempt to
>synchronize the tracks in any way at all.  (and I suspect there were
>many different ways they did it)

Not! I've already replied to Michael by email, but since so many
people have responded to the wrong question and such, I'd better set
things straight:

A normal DOS 3.3 init has a -3 sector stagger (or whatever you'd like
to call it). This means that starting from T0,S0 going outwards to track
$22 you'd encounter sectors (including T0,S0) 0,D,A,7,4,...

Locksmith 5.0 and later versions has a utility (16 sector signature scan)
which determines this pattern, and there is also a discussion in the
manual what it can be used for.


Christer Ericson --- Internet: christer@cs.umu.se --- tel: +46-90-166794
Department of Computer Science, University of Umea, S-90187 UMEA, SWEDEN