[Coco] High(Er) speed cassette loading.

John Kowalski sockmaster at gmail.com
Wed Dec 30 19:23:49 EST 2020


On 12/30/20, Ciaran Anscomb <cocomalt at 6809.org.uk> wrote:
> I always figured the conservative full wave = one bit was to account for
> crappy tape decks that might have some sort of DC offset or similar.  ie,
> a short "high" pulse might actually just be the result of problematic
> playback, accounted for by a longer "low" pulse - measure two zero
> crossings and that sort of thing averages out.

I figured it was just for convenience and also likely that maximum
speed was simply not really that much of a goal.
Unbalanced/biased signal is definitely a possibility, though I imagine
that the idea of including a calibration tone at the beginning of a
file might be a good way to compensate for that.
In theory I suspect we could get tape data rates some 5 to 10 times
faster while still retaining the same reliability.  Who knows how fast
it could really be pushed if we combined a bunch of tricks together.
It'd be pretty cool if it were applied to a large game that somehow
managed to load quickly from tape.

-- 
John Kowalski / Sock Master
http://users.aei.ca/twilight/sock


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