Flash Attack! (was Re: Analog modem emulator?)

[Ethan Dicks]

On 8/5/05, Vintage Computer Festival <vcf at siconic.com> wrote:
> Next time I see the tape (it's around here somewhere :) I'll try to make a
> digital image of it.  Does anyone know if the cassette format on the PET
> is compatible with something more modern like the C64? 

The cassette formats are compatible, but the memory maps are not. 
What that means is a) BASIC programs start at $0400 on the PET and
$0800 on the C-64, and b) you can't do the trick of starting your
mixed machine-language/BASIC program at $033A and have both load at
once.

You can move the location of screen memory around on the C-64 and get
it away from $0400, and move the start of BASIC pointers, etc., to
more closely resemble the PET map.  If the program is 100% BASIC, then
you could load it there and use some other transfer technique to get
it off.  If you have the "PET Emulator" for the C-64 handy, it does
all the pointer fiddling.

If you have a BASIC 2.0 PET handy (I wouldn't recommend this with an
original PET) and a 3040 or 4040 disk drive, you could load the
program on  the PET, save it to diskette, then move the diskette to a
1541 and pull the program in with an X1541 cable.  There were also
programs back in the day to migrate tape programs right to disk.  This
would be a good path if you had a whole PET setup.

Unfortunately, bit-level tape compatibility doesn't encompass the whole problem.

-ethan