Re: Nibble Images ...

[mjmahon@aol.com (Michael J. Mahon)]

Ed Eastman wrote:

>Michael J. Mahon wrote:
>> I thought that DISK2FDI produced ordinary 143KB image files, not .nib
>files.
>> 
>> I would expect that it couldn't read a copy-protected Apple diskette.
>> 
>> This limitation, assuming I'm correct, is not a hardware limitation but
>> a limitation of the software that converts the data read into an image.
>> There is no reason in principle why it could not also create .nib files
>> (I just didn't think that it did it yet).
>
>Disk2FDI does a nibble read and then analyses the bit stream to produce 
>a track read.  That is then 'analysed again' to extract the sector data. 
>  It is then written to a dsk file as sector data.
>
>If the disk is copy protected then the 'second pass' analyse fails to 
>locate sector data.  If Disk2FDI were modified to analyse start of track 
>and write out a fixed length, it too could do nib images.
>
>SST is a cool program.  (I have the source disk.)  Essentially it uses 
>the EDD source code to read a track and analyse it to find start and 
>arbitrarily end it at a fixed length.
>
>There is no reason that someone couldn't write a Q&D program to do that 
>without the transfer stage.  I have EDD source code as well if you want 
>to do that, contact me.

I'd be very interested in seeing the source.  If you could email it
to me, I'd appreciate it!

Perhaps the writer of DISK2FDI could be induced to modify it or
provide its source...

-michael

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