Re: An idea for cheap file transfer

[mjmahon@aol.com (Michael J. Mahon)]

Simon Williams suggested:

>DISCLAIMER: this is idle speculation.

That's the best kind!  ;-)

>By now everyone knows that there is a ton of Apple II software on the
>net. Also that it's a bit of a pain getting it from your PC or Mac to
>the A2 -- well at least for those of us whose 'modern' computers lack
>serial ports.

Fortunately, PCs are still provided with serial ports, and if not, one
(or two) can be added quite cheaply.  Macs are a different breed.

>I was thinking: it should be possible to write some sort of utility that
>would divert the data stream from the cassette out to the speaker when
>using the non-DOS SAVE command. Of course that would be very annoying
>and quite useless on a real Apple II, but I think it could be used in
>conjunction with an emulator to transfer data to the real thing...
>
>Since the sound output from todays computers is much better than a 1978
>Realistic tape player, it should make the process a little easier to
>get working, and the hardware cost would be almost nil. 
>Also, since it would run on any emulator it would be good for both the 
>PC and Mac users.
>
>The problem, naturally, is that I have no idea how this could be
>accomplished. 
>
>Topics for discussion: 
>
>1. Is this idea feasible?
>
>2. If so, is anyone interested in giving it a try?

It is certainly theoretically feasible.

It does have the problem that the SAVE and BSAVE commands are not
the most convenient way to transfer a disk.  And their average speed is
only 1500 bits per second, so patience would be taxed...

And there would still be the problem of getting the level adjusted right
to make the transfer reliable--but that's a one-time problem.

Most emulators already have a reasonable (?) speaker emulation, which
could easily be invoked by cassette output softswitch references.  But I
recall that many emulators running under Windows have "glitchy" sound,
which is annoying to the ear but disasterous to cassette signal decoding.
It would be necessary to generate smooth, continuous sound.

This would require some buffering.

This problem is very similar to the problem of writing a "bit-banged"
serial port in software and then trying to run it on a multi-tasked system.

-michael

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