Re: DSK format specification

["Charlie" <charlied@NOSPAMbboard.com>]

"Michael Pender" <mpender@hotmail.com> wrote in message
news:rLOPa.250$Y%3.201@nwrddc03.gnilink.net...
> Hello,
>
> I'm thinking about adding DSK format support to a program I wrote.  Can
> anyone direct me to a specification for the most current version of the file
> format?
>
> I've read the FAQ, but I need to know the internals of the format, e.g. what
> fields are present, sector ordering, etc.

The "DSK" image format(images that have the extension ".dsk") doesn't seem to
have any written specifications.  As mentioned in Andy McFadden's post some
have different sector orders.  What is really confusing is that there are some
that use a different sector order than the one used by the operating system on
the disk.  In other words there are ProDOS DSK images with DOS order and DOS
3.3 DSK images with ProDOS order as well as DSK images where the order matches
the OS.  ProDOS order means the blocks (512 bytes of unencoded data/block) are
arranged in numerical order.  DOS order is the skewed sector (256 bytes/sector)
arrangement used by DOS 3.3.  Unfortunately, I have run across several DSK
images that have headers (I have no idea how these are used).  Most "DSK"
images are 143,360 bytes in length but again as Andy mentioned there are a few
that have more or less.

Charlie