Re: EDD + CARD

[russotto@grace.speakeasy.net (Matthew Russotto)]

In article <20020725155113.09099.00000672@mb-ch.aol.com>,
Michael J. Mahon <mjmahon@aol.com> wrote:

>If the presence of a non-standard number of 0 bits were not detectable
>by a Disk ][ controller, this so-called "bit stuffing" scheme could not
>be verified to be present, negating its usefulness as a disk "signature"
>technique.

There's a couple of common things that were done without trying to
verify the non-standard self-sync bits directly, such as sticking in
some non-self-sync FFs where there would normally be self-sync FFs.  If
you do it right, you can make a normal "nybble copy" (which will assume
they are all self sync) write too many bits and corrupt the disk, or at
least shrink one of the gaps to a detectably smaller length. 

-- 
Matthew T. Russotto                                mrussotto@speakeasy.net
===== 
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