5 Aug
2005
5 Aug
'05
4:43 p.m.
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