From: jpt@salama.fno.dec.com (Jari Tavi)
Subject: Re: "Are DSP Chips Obsolete?" (was re: Alpha fft performance)
Reply-To: jpt@salama.fno.dec.com (Jari Tavi)
Organization: Digital Equipment Corporation
Date: Thu, 21 Jan 1993 17:29:24 GMT


As a beginning, my personal opinion: I don't think that DSP's are obsolete.
This is not a place to make any product announcements, and because I haven't
read the paper (yet) I can only comment other replys:

In article <1iknq6$6vt@agate.berkeley.edu>, jbuck@forney.berkeley.edu (Joe Buck) writes:

|> Why?  Because it suffers from "all the world's a Unix workstation" disease.
|> (On the other hand, many CS grad students also suffer from this disease,
|> so if the grader knew nothing about the digital signal processing
|> marketplace your report might fool him or her).

Hate to see that "Everything is UNIX" when talked about embedded and DSP
systems too...


|> The paper ignores the issue of cost, power consumption, and weight.
|> Cellular phones are going digital.  These require real time speech
|> compression algorithms in a unit small enough to be hand-held and
|> run for hours on battery power.  For that reason, the future of the
|> DSP industry is going in the direction of "DSP cores" -- the DSP
|> is only part of the chip, and the customer can add whatever other
|> logic is needed.  The goal is NOT to get the maximum number-crunching
|> power; it is to have just enough performance to fit the application
|> and its memory on one chip and have it run in real time.  This
|> means that the engineer has a hardware/software codesign problem:
|> produce a combined solution that gets the job done quickly and
|> for low cost.  Sorry, I don't think that Alpha chips are going to
|> be the answer to the problems the DSP industry currently faces,
|> though I expect that it will make a very nice workstation CPU.
|> 

Cost, power consumtion and such other things are something that you
could try asking if or when they are addressed by Alpha AXP. 21064
will not be the only implementation...

|> The distinction between DSPs and conventional processors is not
|> how fast they do a multiply.  It is their memory bandwidth.  Modern
|> DSPs have multiple memory banks and typically do three I/O operations
|> per cycle.  They are best used in embedded systems, systems with
|> small amounts of memory and very tight timing requirements.

There's nothing in Alpha AXP architecture itself which conflicts with this.
I do agree that 21064 as we see it today may not be something one would use
in cellular phone or something similar, but Alpha isn't bad in issues like
memory bandwith, context switches or interrupt latencies either... in 
addition to number crunching. There are two RT base products we offer:
VAX/ELN and DECelx (68k, MIPS etc.) and these RT environments might 
address these issues quite soon, without the need for general purpose 
operating systm "overhead". Also the way you can build memory and i/o
interconnections to AXP's is very flexible and gives you all you need
to build for example VERY high bandwith memory interconnect logic...

If you have need for High Performance embedded/real Time systems, please
contact sales for product directions. Also Aeon has already implemented
worlds fastest single boarder based on Alpha AXP :-)

regards,

		-Jari
 

--
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Full-Name:      Jari Tavi			
Organization:   DEC Finland                     Dept:           DS/OSG
Tel:            +358-0-434 5252	                Fax:            +358-0-452 1392 
E-mail:         jpt@rixrax.enet.dec.com
Address:        Digital Equipment Corporation Oy
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* All opinions are my personal, and do not necessarily represent opinions of
* my employer! 
Xref: sparky comp.sys.dec:7044 comp.dsp:3057