From: Ralph Smeets <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Sent: Thursday, March 09, 2000 9:06 AM
Subject: Re: MD: Sony's new Internet Audio Recording Interface
>
> [EMAIL PROTECTED] wrote:
> >
> > * "Magic" <[EMAIL PROTECTED]> on Wed, 08 Mar 2000
> > | Fair enough, however, modern DIMMs are much much faster than the RAM
you
> > | would find in the MD. The processor is also much much faster. If it
takes me
> > | 3 instructions to do what the ATRAC chip does in 1, that means I can
do it
> > | at the same speed if my processor does instructions in 1/3 of the
time.
> >
> > You are comparing apples and eggs. The ATRAC DSP does not work the same
> > way a general purpose processor works. The measurement is not how many
> > instructions they can process per second; the measurement is how much
data
> > they can process per second. And the fact remains that a dedicated DSP
can
> > process more data per second than any current generation desktop PC.
>
> that's my whole point. DSPs are designed to do 'number crunching'. I've
> been involved in the functional verification of the ST100 DSP core. Our
> team (including me) verifies also the design of the SH4 (The CPU you'll
> find in the DreamCast). DSP and CPU architectures are completely
different.
> DSP's are optimized to keep the data flowing. However their are NOT
designed
> to handle control tasks (Ie, handle interupts etc.). A CPU however is a
very
> general purpose processor that has to be able to loads of things.
>
> Compare it with cars. If you look at a particular price-class, you'll find
a
> wide range of cars. Varying from sporty cars to mini-vans. The sports-car
will
> do one thing very well: Going Fast. The mini-van however will transport a
lot
> for you, but they won't go very fast.
Ok. Now assume your sports car is built to be price-economical (ie. at a
price that a large number of people can afford rather than absolute
state-of-the-art technology that hardly anyone except the super-rich can
afford). It would probably have a reasonable top speed, reasonable handling,
look pretty good.... for all accounts a nice little consumer sports car.
Now compare that with the Van. It's engine doesn't do a lot of work because
it has been suped up - it has a didicated system handling steering, another
handling suspention, it even has secondary engines to help maintain momentum
when it moves. In fact, it has so many of these things in it that the actual
engine itself really just handles more co-ordination of these other devices
than anything else, and only has a high demand put on it when you need to
really drive the system..... say climbing a steep hill for example. Now
assume that this engine is actually very very powerful - far more so than
the engine in the sports car in terms of speed.
The question is, will the suped-up van outperform the sports car? Given it's
extra power advantage and assistance from other devices, I would think it
probably could.
> If you build a DSP for one special purpose, you'll be able to optimize the
> core even more. Looking at the evolution of ATRAC, I believe that until
the
> birth of ATRAC 3.x, Sony was unable to design an ATRAC encoder that was
fast
> enough to do the encoding 'unoticable'. Why do I come to this conclussion,
> simple:
> - Sony knew how they could improve their algorithm and therefore build a
> decoder that could handle future encoding schemas.
> - ATRAC 3.0 and higher implements 3 frequency bands that can be modified.
Ie,
> they aren't fixed like ATRAC 1 and 2. This requires a lot more
processing
> power.
There's also another thing to consider - size. It may be that a P166 could
perform the ATRAC encoding, but an MD with a P166 processor in it wouldn't
be portable and would probably require vast amounts of cooling to prevent it
burning you if clipped to a belt! It could be that the power is there but
*not* in the super-small componants required for a personal player. Take the
Athlon 700MHz for example - it's a big big processor with a lot of cooling.
They haven't made one small enough to fit in a laptop PC yet, let alone
something as small as a portable MD!!
Magic
--
"Creativity is more a birthright than an acquisition, and the power of sound
is wisdom and understanding applied to the power of vibration."
Location : Portsmouth, England, UK
Homepage : http://www.mattnet.freeserve.co.uk
EMail : [EMAIL PROTECTED]
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