Re: DSK format specification

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

"Bill Garber" <willy46pa@comcast.net> wrote in message
myqdnVYa1ach4o2iXTWJhw@comcast.com">news:myqdnVYa1ach4o2iXTWJhw@comcast.com...
>
> "Charlie" <charlied@NOSPAMbboard.com> wrote in message
> beppol026me@enews2.newsguy.com">news:beppol026me@enews2.newsguy.com...
> >
> > "Michael Pender" <mpender@hotmail.com> wrote in message
> > news:rLOPa.250$Y%3.201@nwrddc03.gnilink.net...
> > 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.
>
> You all are making DSK too complicated. All they are is this.
> Track 1, sector 1, byte 1 is byte 1 of the file, and so on each byte
> from the disk is sequential in the file. Nothing more.

Well, even assuming that you mean track 0, sector 0, and byte 0 this would only
be true of ProDOS order DSK images and I believe that the majority of DSK
images are DOS order.  The bottom line here is that the DSK format isn't really
a format at all.  It is a catch-all for several kinds of formats.  If the
original poster used the sequential order that you describe for his program it
would only work with some DSK images.

Charlie