Re: NEWSFLASH! Linux ported to Commodore VIC-20!!

Peter Monta (pmonta@halibut.imedia.com)
Mon, 14 Sep 1998 12:59:20 -0700


> > How much data would an audio tape be able to carry? Are we talking a
> > few hundred kilobytes or are we in the megabyte range?
>
> On a CBM64 with fastloader, 50K took about 2 minutes. So a C-90 tape gives you
> about 2 MB.

Hm, 3 kbit/sec. Soundcard/tape has high SNR and is quite linear; one
could use some V.34-like QAM/TCM scheme but at a higher symbol rate.
If V.34 can get 30 kbit/sec from a phone line, surely a tape deck with
15 kHz bandwidth would roughly quadruple this, giving around 80 MByte
per 90-min tape. Would want to interleave to control dropouts.

I wonder how fast such tape recorders could go if you stripped off the
linear stuff. Just talk to the write head directly (with a bit on the
parallel port say); would need an amplifier on the read end, with the
machine sitting in a tight loop watching the transitions (some RLL
channel code, or maybe even PRML with a small A/D).

Cheers,
Peter Monta pmonta@imedia.com
Imedia Corp.

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