Re: ADT for the Comm Card, plus a new utility for .DSK image files

[pausch@saafNOSPAM.se (Paul Schlyter)]

In article <39348DF3.54FE5840@swbell.net>,
Rubywand  <rubywand@swbell.net> wrote:
 
>> My only Apple II disks which remain to be transferred are a few
>> 13-sector disks, plus some "copy protected" disks.  They'd probably
>> work fine as "nib" disk images -- but does anyone know a piece of
>> software which works like ADT but which transfers any kind of disk,
>> and produces a "nib" disk image on the PC side?  Yes, I expect that
>> it'll require the Super Serial card, and will need modification to
>> work with the Comm Card, so it's preferable if assembly source
>> code is available on the Apple II side.
>  ....
> 
> For the 13-sector diskettes, have you tried using Muffin to convert them
> to 16-sector diskettes?
 
OF COURSE !!!!  I transferred as many files on my 13-sector diskettes
as I could to 16-sector diskettes decades ago!  Those 13-sector diskettes
which remains are only those which Muffin and friends cannot handle.
 
> I do not know of any util package which converts protected disks to .nib
> on the PC-- i.e. a sort of ADT package that makes .nib files. The problem
> would be on the Apple II side. Some protection schemes require special Copy
> II+ (Locksmith, etc.) parms and/or a Computist-style controller in order to
> produce a deprotected copy or a .nib.
 
I wasn't talking about deprotection, merely about creating .nib disk
images as (hopefully) faihtful copies of the nibbles on the Apple II
disks - these .nib disk images would be just as "protected" as the
original "protected" disks, i.e. normal Apple copy programs would be
unable to handle these .nib images.
 
As far as I see, converting ADT to do this wouldn't really be that
hard: all you'd have to do would be to read in one whole track, as
nibbles, without trying to decode it into sectors and stuff (this
cannot be done through the RWTS but must be done by accessing the
disk controller card directly.  It's not hard to do - examining a
disassembly of the RWTS will reveal how to do it), and then send the
nibbles directly to the serial port, and have the ADT on the PC write
it out as one "track" of a .nib disk image.
 
This method ought to work for any Apple II disk (except those who use
"protection" schemes such as half-tracks, spiral tracks, a small,
controlled, physical defect on the disk, or writing extra zero bits
after a few selected nibbles on the disk).  The only problem at the
Apple side would be to determine where the track starts (presumably
where, say, 10 or more FF's after one another is encountered in the
nibble stream).
 
Another problem is of course that there's absolutely no error check
when reading the Apple diskette: since you make almost no assumptions
on the stored disk data, you cannot use checksums stored on the disk.
One possible way to overcome this could be to read the track twice
and compare the readings: if they differ, a third read is used to
form a "majority vote".
 
I might try to do this some day -- I just wanted to know if someone
else already had done it.
 
 
> Most likely, you will need to use SST to create .nib files or check
> Computist for deprotection info.
 
Yep, I've checked that method too -- I'll probably try it first.  But
it involves many steps, and it would indeed be convenient to be able
to do it in just one step.
 
And it's fun to go back to some 6502 assembly language programming
now and then.
 
-- 
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Paul Schlyter,  Swedish Amateur Astronomer's Society (SAAF)
Grev Turegatan 40,  S-114 38 Stockholm,  SWEDEN
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