On Mon, Apr 6, 2009 at 4:30 PM, Marko Mäkelä <msmakela@gmail.com> wrote:
> Please have a look at the c2n source code.  That program will decode and
> encode Commodore tape images...
>
> ...Commodore format, because each block is set twice
> and because there are three different pulse widths in use, as opposed to
> two.  It's easy to detect byte boundaries.  To decode these broken tapes
> (mostly BASIC programs), I wrote a Perl script to decode the pulse stream
> and edited the binary in GNU Emacs.

This sounds interesting to me - I have a number of tapes that I've
already read in and archived the contents of on modern machines
(mostly stuff I wrote, but a few commercial tapes I bought in the late
1970s), but I probably have a small stack of tapes that had read
errors, at least one of which is commercial (and occasionally had read
problems back in the day).

> If you want to see a slow format, try KIM-1. :-)  It's also supported by
> the "c2n" program.

I don't have any KIM tapes (though I do have a MicroKIM), but I do
have a number of "PET Rabbit"-format tapes.  I have the Rabbit program
on ROM and on C= tape but have not yet attempted to reverse-engineer
it.  What sort of information would I have to know about the format to
consider adding it to the c2n program?  I doubt there's m uch
documentation about it already, so I'm guessing I'll have to get the
code to tell me.

My plan right now was to finish repairing my 1978 32K PET (it has
reliability problems talking to IEEE devices that I think are bad
40-pin sockets on the VLSI chips) then just try to read these tapes
using the ROM Rabbit and save them out the C2N232.  It would be nice
to just be able to slurp up these tapes with modern hardware and save
a couple of steps.

I have at least a dozen tapes with archives of code I wrote (mostly
games, some utilities) between about 1979 and 1982, stuff I'd like to
look over again.  Probably the most interesting thing in the
collection is a machine-language "Scott Adams" interpreter I wrote
first using TIM and entering the code in hex, then later, by using the
one-line-at-a-time assembler in one of the extended monitor programs
(SuperMON?)  It plays Adventureland, Pirate Adventure _and_ Castle
Adventure by David Malmberg.  One of my long-term projects is to
extract my hand-written code to source and getting it to the point
that it will work with an assembler so I can a) publish it, and b)
make sure it works with games that I never saw 30 years ago.

So the question is what I need to discover about the tape format in
order to add support for it in c2n.

Thanks,

-ethan


       Message was sent through the cbm-hackers mailing list