Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!usc!sdd.hp.com!hplabs!hpda!hpcuhb!hpcuhe!linley
From: linley@hpcuhe.cup.hp.com (Linley Gwennap)
Newsgroups: comp.arch
Subject: Re: Snake
Message-ID: <32580004@hpcuhe.cup.hp.com>
Date: 25 Mar 91 22:54:36 GMT
References: <69465@brunix.UUCP>
Organization: PA-RISC Marketing Central
Lines: 32

(Curtis Yarvin) asks:
In today's New York Times, there is an article about the new HP Snake line.
The story places the low-end Snake (720?) at 57 MIPS, 55 Specmarks for
$12,000.

This will obviously cramp the digestion of competing workstation makers.

Does anyone know how these numbers were achieved?  Are they misleading in
any way?
----------

Yes, they are misleading.  The performance on real applications (not
toy benchmarks) is actually significantly *higher* due to the much larger
caches (128KB I/256KB D) than competing systems.

The CPU in the Model 720 is a traditional RISC implementation (no "super"
stuff) that runs at 50 MHz using fairly standard 1.0 micron CMOS process. 
I could go into great detail, but basically the high performance is due
to eliminating most pipeline interlocks and keeping the chip simple
enough to allow the high clock frequency.  The compilers have also been
closely tuned to the hardware.  The PA-RISC instruction set is rich
enough to offer some instruction-level parallelism (e.g. COMPARE-AND-
BRANCH, ADD-AND-BRANCH instructions) so that superscalar complexities
are not needed.

Yes, these system run UNIX (HP-UX) and most common applications, over
2000 total.  All Series 700 systems are also source-code compatible
with our popular Motorola-based workstations.  By the way, if you need
more performance, a 66 Mhz Model 730 is available for $20,000.

						--Linley Gwennap
						  Hewlett-Packard