Re: Disk Image to cassette tape

[Rubywand <rubywand@swbell.net>]

SEAN BURNETT writes ...
> 
> Hi,
> I would like to do this on an Apple II/e:
> -> copy a 5 1/4" diskette onto a tape cassette as a disk image (using
> the "cassette out" peripheral.  Are there any utilities out there that
> will allow me to do this?  Is this something i can do with just regular
> dos 3.3 commands?  Does anybody know anything about using the cassette
> out with an Apple II/e?
> 

 ....

     There is a built-in limitation which would prevent saving a disk
image to cassette via the standard Apple II Tape routines. A standard
disk image of a 5.25" diskette is 143,360 bytes in length. The Apple II
Tape routine permits saving from memory up to 65,536 bytes.

     Is it possible to save a 140kb disk image to cassette? Yes; but,
you would need to break up the image file into smaller pieces. One idea
is to add your own routines to do something like read chunks of the disk
image file (perhaps 4096 bytes per chunk) and write the data to tape.
Then you would need a Big File tape read routine to read the chunks and
put them on disk.

     In any case, the files on the tape copy of a disk image would not
be accessible from tape (unless you went to a _lot_ of bother to set up
special routines to treat a cassette tape like a diskette). The cassette
copy would just be an archive. You would need to move the disk image to
a diskette or RAM disk to access the files under DOS or ProDOS. 


     If the idea is to get the stuff from a disk image onto tape in a
form runnable from tape, one approach would be to move the image to
diskette and, if the result is a standard DOS or ProDOS diskette, move
the files to tape. Some older games and utilities can be loaded and run
from cassette. Some others can be modified to run this way. And, a
determined user could develop a Tape Operating System which could encode
file ID info, search for files, etc. and simulate disk operation with
cassette tape.

     In general, though, there is no advantage to using cassette vs.
diskette.



Rubywand