Re: DSK to NIB Instruction

[Andy McFadden <fadden@fadden.com>]

Knut Roll-Lund <kr-lund@nogarbage.online.no> wrote:
> The nib format seems to be each track as it would be seen by the drive 
> head that is 416 bytes times 16 sectors times 35 tracks. Sometimes it 
> seems that it is sectors still, not tracks, but some nib files seems to 
> be starting in the middle of a sector so it is probably tracks, even 
> when each sector is 416 bytes.

A .nib file is 6656 ($1a00) bytes of raw data read from the floppy drive.
It's just about impossible for a track to actually be that long, so you
have some overlap.  Sadly, information about sync bytes is not retained.

The .dsk files created by SST take the 6656 bytes of data and spread
them over two 16-sector tracks so you can copy them over with SST.
Merging these back into a single .nib file is awkward but doable
(CiderPress does it).

> I would be interested in a tool that would do the opposite of the 
> question in this thread, to break a nib into two dsk images that can be 
> used with ADT and SST "unpack" on a real Apple. SST fails miserably in 
> the emulators doing this, to "pack" a nib into two dsk images. If 
> someone would point out an emulator where SST pack wouldn't fail that 
> would also help.

I imagine the track analyzer has some trouble finding the length of the
track.  A simple-minded data copy might actually work better.

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