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Re: Hardware gadget for tape loading
On Sat, 18 Sep 1999 12:55:19 GMT, greenaum@BOLLOCKSyahoo.co.uk wrote:
>It would be better to use the sound card, since these outnumber little
>parallel port gadgets by a hundred to one.
Speaking for the Atari 8-bit machines, I wrote a program in 'C'
back in 1997 to read Atari cassettes using a sound card on the PC.
The data is extracted and saved. You can send that data to
the Atari.
The Atari reads the cassette as a 600 baud serial device, so the
data can be sent over the PC's serial port to the Serial IO bus of the
Atari. Only a simple voltage level adapter is needed, as the ones
already in use for the disk drive emulators SIO2PC and APE.
>I think the TZX format is flexible enough to hold other computers'
>formats, have a look at the specs and see if it's suitable. It would
>be quite good to see a common tape format, it would mean the utilities
>for digitising and re-tapifying tapes, could be centralised and have
>much more time put into them, better sampling techniques, etc, so
>everything would be better.
Well, I did not know of this format or these utilities. I looked at
the format specification, and to me it looks very complicated.
Flexible yes, but also very very complicated.
>Can TZX have meta data put in it, so you can store what computer it's
>for and who sampled it etc? I know I could just go look it up but it
>needs bringing up anyway.
I think this is possible. But I do not know why anyone would want
this. Tapes for one system cannot be loaded on another system.
I think it is very confusing to store all sorts of tape files for
different machines in the same format. Like, I have a ton of
diskettes. Some are for the PC. Some for the Atari ST. Some for the
Atari 8-bit machines. Some for macintosh. Some for Wang Classic,
some for Wang VS. And then some for emulator use. Sometimes it is
hard to tell what is what.
The same problem would arise with these emulated cassettes.
If searching for a tape file, you might get confused. The only
advantage is the one you mention, we can share knowledge
and technology, and thus improve the tools. I think we can
accomplish this easily if the developers get in touch with each other.
We do not need to bother the users with this, making life harder for
them.
>Do the current samplers just look for 0 transitions, or something?
>Maybe a bit of low and high-pass filtering could help clean up old
>tapes. etc etc, there must be loads of things to make sound card
>loading more reliable.
My conversion program counts the number of samples between a
high and a low value in the wave file. My program comes with the
documentation and 'C' source code. They only work for the Atari
8-bit, since that is the only system I know about. I have no
technical knowledge of other systems, and I really do not care
about them anyway. I hate tapes. That is why I wrote these
programs. But the signal processing is not too bad.
I did not want to sample in real time, because that adds complexity
to the program. Besides, I know nothing about reading from a
sound card. If you sample to a wave file, you can edit and try
to repair the wave file, if drop-outs and other stuff appear on the
tape.
Begin this year I also wrote a program to convert the data back
to audio, so the wave file can be recorded on a cassette tape
again after cleaning it up.
My programs do not look nice and flashy, but they seem to do
the job. Anyway, I have received very little feedback, which
makes me believe that on the Atari 8-bit machines, almost
everybody is using emulated disk images, not cassette stuff.
I think all stuff that was released for the Atari 8-bit was also
released on disk. It is much easier to get a disk version.
That is why emulators for the Atari do not support the
cassette unit. Nobody needs it. So no need to support
cassette emulation either.
My stuff can be used to recover programs that people
wrote themselves and saved to tape. Anyway, used or not,
my stuff is available free from the Umich archives, and can
also be found on my home-page. If you are interested in
cassette processing software, you can download the
programs, including the 'C' source code from
http://home.planet.nl/~ernest
I only read the comp.sys.atari.8bit news group, although
this is cross posted. Send me an E-mail if you have questions,
or reply in c.s.a.8
Keep those XL's/XE's humming,
Ernest.