Richard L. Sites,
Alpha CPU Co-architect,
Corporate Consultant Engineer
Welcome to the Tenth Anniversary issue of the Digital Technical
Journal! As Jane explains in the Editor's Introduction, much has
changed since Volume 1 Number 1. In fact, much has changed in
only three years, as this issue on Alpha attests.
From Race Cars To Express-Delivery Trucks
What if race cars evolved as quickly as computers? They might
stay on the race track and get about three times faster every
three years. Or they might move off the track into everyday life.
Just three short years ago, Digital was celebrating in these
pages and elsewhere the first-generation Alpha hardware and
software announcements. The typical analogy likened Alpha to a
race car--blazingly fast, but not seen in your own neighborhood.
In this issue, Digital's engineers describe second-generation
Alpha hardware and software. Today's analogy is to an
express-delivery truck--still faster than the rest of the
industry, but now so commonplace in the delivery of business data
that it is almost taken for granted.
If we look back at history, most healthy computer architectures
did not become firmly established in the marketplace until the
introduction of their second generation. Following are
architecture generations for three popular processor designs,
with milestone implementations highlighted. Each architecture
goes through many generations, on about a three-year cycle. The
second generation in each case has been the point at which the
architecture became firmly established. Subsequent generations
have represented continuing refinement and performance increases.
Alpha fits this industry-wide pattern.
IBM System/360 VAX Alpha
-------------- ----------- ------------
Architecture design 1962 1975 1989
First generation 1965 360/40 1978 VAX-11/780 1992 21064
scientific
Second generation 1968 360/85 1982 VAX-11/750 1995 21164 business
Third generation 1971 370/145 1985 MicroVAX [1998 21264]
Fourth generation 1974 Virtual 1988 VAX 6000 :
memory Model 200
370/168
Fifth generation 1977 1991 VAX 6000
Model 600
Sixth generation 1980 1994
Seventh generation 1983 3090 :
Eighth generation 1986
Ninth generation 1989 ES/9000
Tenth generation 1992
:
So, with the advent of second-generation Alpha computers, how are
we doing?
At The Starting Line
The first-generation Alpha hardware designs focused on
performance, especially on high clock rate for the CPU chip. The
initial 150-MHz and 200-MHz Alpha systems entered the market when
the Intel 486 at 66 MHz and MIPS R4000 at 75 MHz were the fastest
chips of their respective lines.
The first-generation Alpha software focused on survival--enough
operating system functionality (VMS subset) to support at least
some customers, and enough compiler optimization to make at least
some (single-user, Fortran, scientific) programs run fast. An
important part of the introduction was migration software to help
the installed base of VAX/VMS and MIPS/ULTRIX customers move to
the Alpha platform. As with any new venture, the approaches were
minimalist, with sophistication left to the future.
Like race cars, the initial Alpha hardware and software was
criticized for being temperamental--fast indeed for some
applications, but not appropriate for others. Some observers
assumed that the first generation was a fluke, or that it
represented all that Alpha computers could ever be. The reaction
to many architectural features, such as 64-bit addressing or
relaxed read-write ordering, was "who needs it?" They wrote Alpha
off as a niche design.
Delivering On Its Promise
Three years later, the future has arrived with a (muffled) roar:
- The sophisticated second-generation Alpha 21164 chip,
described in this issue, is 1.5 to 2 times as efficient
as the first-generation 21064 chip in terms of work done
per clock cycle on real programs.
- The chip clock rate has been boosted from 200 MHz to a
stunning 300 MHz.
- Efficiency of compiled code has improved by 10 to 60
percent on many programs.
- Operating system code has been expanded and tuned.
The performance factors roughly multiply together, producing
second-generation systems that are about 2.5 to 3.5 times faster
than the equivalent first-generation systems. One example of the
higher speeds of these new systems is the AlphaServer 8400,
discussed in this issue; system performance approaches the level
of supercomputers with Linpack nxn results of 5 GFLOPS.
The second-generation system platforms emphasize industry
leadership for a broad range of commercial client-server
applications, not just scientific applications. Like
express-delivery trucks, much of the second-generation software
is focused on enterprise-wide database access. Truly taking
advantage of the 64-bit addressing for the first time, Oracle 7
database software can run huge in-memory database queries 200(!)
times faster than traditional 32-bit database software. The three
database papers in this issue emphasize Digital's focus on
commercial applications.
Operating system support is substantially more robust and has
been expanded to the fastest UNIX and Windows NT implementations
in the industry. Full VMS clustering, including mixed Alpha and
VAX clusters, is available. UNIX and NT clustering is announced.
All three operating systems now support SMP, symmetric
multiprocessing. The 64-bit Digital UNIX implementation has led
the rest of the industry in delivering 64-bit software by over 24
months.
Compiled-code improvements have been remarkable. In 1992, I could
read the code generated by some of our compilers and redline
three out of every four instructions as unneeded unneeded
unneeded unneeded. A year ago, I could read compiled code and
redline one instruction out of every two as unneeded unneeded.
Today, I am hard-pressed to redline even 15 percent of the
instructions as unneeded.
Moving beyond the installed base, migration efforts are now
focused on bringing in new customers. In addition to VAX and MIPS
binary translation, the SPARC-to-Alpha binary translation product
is available. Code from x86 PC platforms runs emulated on all
Alpha operating systems. A technology demonstration of
x86-to-Alpha binary translation has been given at trade shows.
The growing maturity and sophistication of the Alpha products
have in turn led to accelerated sales growth. Over 100,000 Alpha
systems worth over $3.5 billion (hardware, software, and service)
have been shipped, and the ship rate has increased 66 percent in
the past year alone. In its first three years, Alpha is off to a
much faster start than other RISC architectures, such as HP-PA,
in their first three years. Buying patterns have shifted from
try-one-out to buy-a-fleet-to-run-the-business.
In three short years, Alpha computers have become established as
the fastest in the industry--the yardstick by which others
measure computer performance. Competitors have shortened their
development cycles and aggressively increased their clock rates.
Every single company that described Alpha features as unnecessary
in 1992 is now rushing to bring its own 64-bit and relaxed
read-write order SMP implementations to market. Alpha has grown
from "niche design" to "industry yardstick" in a single
generation.
Digital has invested over $1 billion in the Alpha development.
Literally thousands of people have brought a paper design to
life. Bleeding-edge and brute-force chip technology has turned
into practical engineering, with a balance of sophistication and
everyday care: race cars to express-delivery trucks.
Alpha is evolving much as the architects originally envisioned. I
believe Peter Conklin, who led the Alpha Program Office and to
whom this issue is dedicated in memoriam, would want to also
dedicate this issue to all the brilliant and hard-working people
who have made it a reality. My thanks and admiration to each of
you.
So how are we doing? After reading this issue, I think you will
agree "Quite well, thank you."
Intel486 is a trademark of Intel Corporation.
MIPS R4000 is a trademark of MIPS Computer Systems, Inc.
SPARC is a registered trademark of SPARC International, Inc.
Windows NT is a trademark of Microsoft Corporation.
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