That's sort of what I was thinking of. Of course, as you say, it is ZX81
specific.
Were these home computer tape format's standardised in any way, or at least
based on an older standard? I seem to remember a format called
"Cottis-Blandford" from years ago. Am I right in saying that most home
computer's tape data format was 1200Hz and 2400Hz for logic 0 and 1 (maybe
the other way round). How many stop/start & parity bits (and possibly more
control bits) are sent may be computer-specific I guess.
Sampling the audio stream and decoding the 0s and 1s would not be too hard a
task if a sound card with easy access to the sampling hardware was
available. It would then be relatively simple to write an application would
allow the number of start, stop, data (probably 8!) and parity bits to be
selected, world decode the string of 0s and 1s into a byte-file. The format
of this file, again, would be computer-specific of course.
If I get time I may have a go at this.
paul
-----Original Message-----
From: David Holland [mailto:dholland_at_woh.rr.com]
Sent: 17 May 2003 02:36
To: Classic Computer Talk
Subject: RE: Preserving ancient media
The following MIGHT be a good place to start:
http://www.geocities.com/SiliconValley/Ridge/9965/
ZXTAPE 3.0 Its directed towards the zx81, but it could
be applicable to your application. Dunno. I've a feeling every
computers tape format is different, though.
David
On Tue, 2003-05-13 at 03:25, Hills, Paul wrote:
> I have quite a bit of software on cassette tapes for 1980s home computers.
> Does anyone know of a simple method (without having to design and build
> myself a dual-tone decoder circuit + write suitable PC software) of
getting
> this information onto a PC? I guess the home computer emulator pages on
the
> web must have done this.
>
> Maybe I could record it as a WAV file then write a program to decode the
> WAV? Or would MP3 encoding be capable of compressing and reliable
expanding
> the audio data (MP3 is of course designed to compress music which these
> squeaks and whistles clearly are not, even if they lie within the audio
> spectrum!).
>
> paul
Received on Mon May 19 2003 - 09:56:12 BST