[Coco] tape format

[Art Flexser]

I seem to remember 1800 baud as being the figure given, presumably because it is
the average of 1200 and 2400.

Art

On Wed, 19 Nov 2008, Joel Ewy wrote:

> Roger Taylor wrote:
> > At 09:02 PM 11/17/2008, you wrote:
> >> Hi Roger,
> >>
> >> For some reason, I thought the Coco did have 1500 Hz cassette system.  I
> >> seem to remember it being exactly 5 times faster than the Commodore.
> >>
> >> In any event, what was the speed of the Coco cassette?
> >>
> >> John
> >
> > They claim an average of "1500 baud" because of the random assortment
> > of 1200 hz and 2400 hz sine waves.
> >
> > The 2400 hz wave is only output once on a CoCo.  Some old vintie
> > systems output 2 of the 2400 hz waves so the duration is the same as
> > the 1200 hz wave.  To me this would probably give better reliability
> > with cheap tapes depending on the formula, averaging, and testing used
> > in the load-back code.  The problem has always been the drag on the
> > tape causing the record and play rates to both vary slightly over
> > time, like if you held your finger on one of the rotors ever so
> > slightly similar to slowing down an LP record platform.  This is why
> > data stored in blocks loads back more reliably.  The loader gets a
> > chance to get back in sync more often.
> > I just think that with our modern way of thinking and time-tested
> > experiments over the ages, that a much faster and reliable tape audio
> > format could be created that would blow the lid off the old format,
> > even using cheapo tapes.  I *might* save all that for a rainy day
> > after cocotape.exe is done, but I doubt it.
> >
> > Btw, cocotape will have a ~1mhz and ~2mhz save option so you can type
> > POKE 65495/7,0 on the CoCo and load twice as fast from the PC since
> > it's a perfectly steady audio stream with no tape drag or drop
> > factor.  The default will be the ~1mhz speed, ofcourse.
> >
> So, could you come up with a client/server system where you CLOADM a
> small routine at 1MHz from the host PC which auto-executes, patches
> BASIC's cassette routine (assuming CoCo 3 or RAM-able 64K CoCo) for the
> faster protocol, and optionally switches the computer to 2MHz?  Then
> subsequent loads would zip.
> 
> JCE
> 
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