Re: .DSK images with 40 tracks?

[Holger Picker <pickerh@uni-muenster.de>]

On 12 Mar 2003, Dosius wrote:

> Date: 12 Mar 2003 14:09:26 -0800
> From: Dosius <steve@dosius.zzn.com>
> Newsgroups: comp.sys.apple2
> Subject: Re: .DSK images with 40 tracks?
>
>
> I'd like to see an extension (160K DO?), maybe just a file-size check
> on DSK images to autodetect 40-tracks.
>
> -uso.
>

Hi Dosius,

how about introducing 40 track disk images to Dapple][ then? May I suggest
the following, please:
i) Implement a flag via the disk menu that allows to switch between a 35 and
a 40 track disk drive. Let's say it's called drive3540flag.
ii) Do a simple file size check to determine whether a .dsk (.do, .po) image
has got 35 ot 40 tracks and set up a second flag accordingly. Let's call this
one disk3540flag.
iii) Put in a third flag that gets true whenever the disk drive _writes_ to
a track > 34. This is to convert a once 35 track disk image to a 40 track
disk image if necessary. Call this one write40.
iv) When storing a disk image, check a) the disk3540flag. Is it true, then
always store as a 40 track disk image. b) Otherwise if 'write40' is set,
also store the disk as a 40 track disk image. c) If neither is true, it's
still a good old fashioned .dsk 35 track image as before.
Perhaps we could see something like this in the next release of Dapple][?

Another thing I'd like to know: Is there a disk format somewhere used by
emulators which stores a disk as a 80 half-track disk image? (May be
compared to the .G64-format used by C64 emulators.) The point is: even the
.nib format does not allow you to store programs that use half tracks as a
copy protection. A 80 half-track disk image could be used to store almost
everything ever put on a disk as a file for the emulators. I personally
would love to see old programs run on emulators as they were meant to run by
the authors. (Sorry, but I'm not a friend of these "cracker screens" etc.)
Of course, there would still be the problem of how to get the original disk
to the PC/Macintosh... I'm afraid, I don't know anything about that. All I
could do is to take care about an "accurate" disk emulation. Any ideas someone?
Kindest regards

  Holger