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

Andrew Snare (ajs@pigpond.com)
15 Sep 1998 16:18:06 +1000


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>>>>> "Chris" == Chris Zwilling <chris@cloudnet.com> writes:

Chris> There are many problems with tape. Stretching and speed
Chris> drift have been touched on. Tape alignment is another one.
Chris> How about wow and flutter? Then we have abrasion - taking
Chris> the emulsion right off the tape. If we limited ourselves to
Chris> one channel on a stereo deck, we could have RAID-1 type
Chris> redundancy. ;)

Chris> Of course we could try a simple experiment. Take a sound
Chris> sampled from CD. Record it to the tape deck with the sound
Chris> card (dd if=sample.raw of=/dev/dsp bs=512
Chris> count=128). Resample from the tape and compare the results
Chris> with the original sample (dd if=/dev/dsp of=sample2.raw
Chris> bs=512 count=128). My guess is that although the files will
Chris> sound similar the byte differences will be quite large. You
Chris> can generate some random data by catting /dev/random to a
Chris> file.

There's also the problem that the ADCs found on most soundcards are
pretty ordinary. A friend was working on a new sound-compression
project, and as part of his work sampled the audio from the CD-ROM
drive. He then compared the result to the raw digital data on the CD
and found that when using 16-bit sampling the bottom 5 bits were
"random". This means that either the CD-ROM DAC was crap, the audio
cable was noisy, the sound-card's ADC was crap, or all of the
above. When you consider the likely price of the ADC used on the
average sound-card and compare it to "scientific" ADCs, you can
understand that the sound-card's ADC must leave a lot to be desired.

This could put a bit of a damper on what is achievable, but then again
this might not be a limiting factor depending on the encoding scheme
used. :)

- Andrew

-- 
#!/usr/bin/env python
print(lambda s:s+"("+`s`+")")\
('#!/usr/bin/env python\012print(lambda s:s+"("+`s`+")")\\\012')
print(lambda x:x%`x`)('print(lambda x:x%%`x`)(%s)')

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