Re: How to make .nib disk images?

[Rubywand <rubywand@swbell.net>]

Ron Kneusel writes ...
> 
> Does anyone know the format used for .nib disk images and which
> emulators will read these images for non-standard DOS.  Ie, AppleWin,
> at least the one with source code available, seems to look specifically
> for the header bytes used by normal DOS/ProDOS.

     It would do that for a 5.25" .dsk disk image to determine the
order of the data (DOS 3.3 or ProDOS sector ordering).  For a .do image,
it should assume DOS 3.3 ordering; and, for a .po image it should assume
ProDOS ordering.

     There should be no special checking for a .nib image (except for
file kind and length) because a .nib image simulates an actual diskette.
All the information necessary for a good disk drive + controller emulation
to boot and use the diskette should be available. (Which is why a .nib
image is so much larger than a .dsk image.)


> 
> I want to be able to make a .nib image from a non-standard DOS floppy
> and know which emulator is likely to run it.  Note, I do not want to
> know which _programs_ make .nib image but how to write a program to make
> my own.
>

     Seems like I read somewhere that the old time .nib maker program (SST)
uses bit copy routines from Essential Data Duplicator (EDD). Instead of
writing the copy to another disk, SST writes the stuff as data to a couple
of disks. I think the data probably looks like what you get when you do
a 'raw track' display under most bit copiers.

     As long as the protection scheme is not too weird, you can 
transfer and combine the contents of the two disks to recreate the original.
A .nib file is the contents of the two disks combined into a single file.

     There may be a few cases where the closer (slower) drive emulation 
option available in Apple Oasis makes a difference in using a .nib
image of protected software. In most cases, speed doesn't seem to matter
and AppleWin works fine.



Rubywand




> Any help appreciated.  Apologies for anything above that is unclear.
> 
> Ron Kneusel
> oneelkruns@hotmail.com