Defining Disk Image Dump Standard

From: Eric Smith <eric_at_brouhaha.com>
Date: Wed May 31 19:21:01 2000

> What encoding method did it use? 4&4 or 6&2? I'll assume 6&2?

6&2.

> > pretty good. However, there was no reason why the same performance (but
> > not density) couldn't be achieved with standard sectors. The Apple ///
> > SOS disk driver pioneered this, and IIRC Prodos did it as well.
>
> Sure, read the raw track into a buffer in memory and then process it. The
> only drawback is the requirement for a relatively large buffer.

No, the trick (as used in SOS, and in the Lisa I/O card ROM) is to
do 1:1 interleave *without8 a track buffer. They directly denibblize
as they're reading the bits from the disk.
Received on Wed May 31 2000 - 19:21:01 BST