The Logic Off Topic list

marc lindahl:

> the best long term format (practical) so far is optical - like
> CDROMs, DVDROMs. 

I'm curious about DVDr... Does it work on the same burn-dye-to-imitate-pits
strategy as CDR?  I like the idea of DVDr, but I'm not sold that
miniaturized CDr technology boasts the same reliability or longevity as full
size.

> Longer lifespan than analog tape....

Hmm.  The problem is that digital degrades so ungracefully.  Shannon's
theories allow you to predict how much EC overhead you'll need to insulate
the information from the noise of the "noisy channel", but your calculation
becomes invalid as the noise in the storage channel increases over time.
All of a sudden, the EC fails, and you have dropouts.  Depending on how the
information is organized, this commonly results in complete dropouts in the
reconstructed waveform or huge glitching.

In contrast, when analog magnetic media goes south, you may get HF loss, or
warbles, but by and large, the perceptual effects are not as severe.  Also,
sticky-shed syndrome does not affect all tape formulations.  We just played
back somebody's acetate tape from the 60s with no conditioning other than
repack onto a better reel.

Interesting tidbit: "scalable" codecs implemented as part of MPEG 4 behave
more like analog media, as dropouts result in a momentarily degraded signal
rather than total loss.  As packets are lost, the sample rate gets cut back,
and the coding gets rougher, but the signal doesn't go away completely.

Here's a neat link that talks about the need to analyze the types of errors
that your system will experience if you're to optimize it for best
performance:

http://www.ednmag.com/ednmag/reg/1997/110697/23df_06.htm

The problem with all of the storage solutions that digital audio sponges off
the computer industry is that no one in computer R&D has market pressure
driving them to think about making storage that lasts decades or centuries!

> the nice thing about digital, if you have the time to do it, is if you make
> bit-perfect backups, then you've 'reset the clock' on the lifespan,
> something you can't do with analog.

It can be done, but will it be done?  Risky thing to assume.

Back to the original subject:

These Seagate drives with the fluid bearings... your misgivings are in
regards to short term reliability, I assume.  Mean time failure rate...
Since it's a new technology, wait-and-see is probably a good idea...

But imagine one of those Apple G4 Cubes outfitted with a quiet HD... no fan
noise, no HD noise (supposedly).  You could actually have one of those in
the room with you as you record.  A lot of DIYers have been waiting for that
for a while.

-- Marvin Humphrey
Mastering Engineer and Graphic Designer, emeritus
CD design website - http://marvin.mrtoads.com