Computer (March 2005)

101 Pages·2005·4.067 MB·English

Innovative Technology for Computer Professionals
March 2005
Engineers, Programmers,
and Black Boxes, p. 8
Building the
Software Radio, p. 87
The Winner’s Curse
in High Tech, p. 96
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Innovative Technology for Computer Professionals
March 2005,Volume 38,Number 3
COMPUTING PRACTICES
26 Integrating Biological Research through
Web Services
Hong Tina Gao, Jane Huffman Hayes, and Henry Cai
A case study demonstrates that Web services could be key to
coordinating and standardizing incompatible applications in
bioinformatics, an effort that is becoming increasingly critical to
meaningful biological research.
COVER FEATURES
33 Socially Aware Computation and Communication
Alex (Sandy) Pentland
By building machines that understand social signaling and social
context, technologists can dramatically improve collective decision
making and help keep remote users in the loop.
41 Designing Smart Artifacts for Smart Environments
Norbert A. Streitz, Carsten Röcker, Thorsten Prante, Daniel van
Alphen, Richard Stenzel, and Carsten Magerkurth
Smart artifacts promise to enhance the relationships among
participants in distributed working groups, maintaining personal
mobility while offering opportunities for the collaboration, informal
communication, and social awareness that contribute to the synergy
and cohesiveness inherent in collocated teams.
50 The Gator Tech Smart House:
Cover design and artwork by Dirk Hagner A Programmable Pervasive Space
Sumi Helal, William Mann, Hicham El-Zabadani, Jeffrey King,
ABOUT THIS ISSUE
Youssef Kaddoura, and Erwin Jansen
Increasingly inexpensive consumer electronics, Many first-generation pervasive computing systems lack the ability
mature technologies such as RFID, and to evolve as new technologies emerge or as an application domain
emerging wireless sensor technologies make matures. Programmable pervasive spaces, such as the Gator Tech
possible a new era of smart homes, offices, and Smart House, offer a scalable, cost-effective way to develop and
other environments. In this issue, we look at deploy extensible smart technologies.
state-of-the-art technology applications including
socially aware communication-support tools; 61 Web-Log-Driven Business Activity Monitoring
programmable pervasive spaces that integrate
Savitha Srinivasan, Vikas Krishna, and Scott Holmes
system components; smart environments that
Using business process transformation to digitize shipments from
incorporate information, communication, and
IBM’s Mexico facility to the US resulted in an improved process that
sensing technologies into everyday objects; and an
reduced transit time, cut labor costs and paperwork, and provided
industry-specific initiative that uses a Web-based
instant and perpetual access to electronically archived shipping
approach to bring processes, people, and
records.
information together to optimize efficiency.
IEEEComputer Society:http://www.computer.org
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OPINION
8 At Random
Engineers, Programmers, and Black Boxes
Bob Colwell
NEWS
14 Industry Trends
Search Engines Tackle the Desktop
Bernard Cole
18 Technology News
Is It Time for Clockless Chips?
David Geer
22 News Briefs
Finding Ways to Read and Search Handwritten Documents (cid:1)
A Gem of an Idea for Improving Chips (cid:1) IBM Lets Open Source
Developers Use 500 Patents
MEMBERSHIP NEWS
75 Computer Society Connection
80 Call and Calendar
NEXT
COLUMNS
MONTH:
87 Embedded Computing Beyond
Building the Software Radio Internet
Wayne Wolf
93 Standards
Public Opinion’s Influence on Voting System Technology
Herb Deutsch
96 IT Systems Perspectives
The Winner’s Curse in High Tech
G. Anandalingam and Henry C. Lucas Jr.
100 The Profession
An Open-Secret Voting System
Thomas K. Johnson
DEPARTMENTS
4 Article Summaries
6 Letters
12 32 & 16
70 Career Opportunities
73 Advertiser/Product Index
83 Products
86 Bookshelf
90 IEEE Computer Society Membership Application
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Innovative Technology for Computer Professionals
Editor in Chief Computing Practices Special Issues 2004 IEEE Computer Society
President
Doris L. Carver Rohit Kapur Bill Schilit
Louisiana State University [email protected] [email protected] Carl K. Chang
[email protected] [email protected]
Perspectives Web Editor
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in Chief
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Bill N. Schilit
Research Features
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Computer Architectures At Random Security Michael R. Williams (chair),
Douglas C. Burger Bob Colwell Bill Arbaugh Michael R. Blaha, Roger U. Fujii, Sorel
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OMT Associates Inc. Technology US Army Research Laboratory CS Magazine Operations
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Graphics and Multimedia Embedded Computing Advisory Panel
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James H. Aylor
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University of Virginia George Cybenko, John C. Dill, Frank E.
Information and Entertainment Computing Thomas Cain Ferrante, Robert E. Filman, Forouzan
Data Management Michael R. Macedonia University of Pittsburgh Golshani, David Alan Grier, Rajesh Gupta,
Naren Ramakrishnan Georgia Tech Research Institute Ralph Cavin Warren Harrison, James Hendler,
Virginia Tech IT Systems Perspectives Semiconductor Research Corp. M. Satyanarayanan
Multimedia Richard G. Mathieu Ron Hoelzeman
Savitha Srinivasan St. Louis University University of Pittsburgh
IBM Almaden Research Center Invisible Computing Edward A. Parrish
Networking Bill N. Schilit Worcester Polytechnic Institute
Ron Vetter
Jonathan Liu Intel
University of North Carolina at
University of Florida The Profession Wilmington
Software Neville Holmes Alf Weaver
H. Dieter Rombach University of Tasmania University of Virginia
AG Software Engineering
Dan Cooke
Texas Tech University
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2 Computer Published by the IEEE Computer Society
A R T I C L E S U M M A R I E S
Integrating Biological Research Designing Smart Artifacts geneous elements is mostly a manual, ad
through Web Services for Smart Environments hoc process. The environments are also
pp. 26-31 pp. 41-49 closed, limiting development or exten-
Hong Tina Gao, Jane Huffman Hayes, Norbert A. Streitz, Carsten Röcker, sion to the original implementers.
and Henry Cai Thorsten Prante, Daniel van Alphen, To address this limitation, the Uni-
Richard Stenzel, and Carsten versity of Florida’s Mobile and Pervasive
A
t present, compatibility problems Magerkurth Computing Laboratory is developing pro-
prevent researchers from cooperat- grammable pervasive spacesin which a
T
ing in using bioinformatics to solve he integration of information, com- smart space exists as both a runtime envi-
important biological problems. munication, and sensing technolo- ronment and a software library. Service
Web services might be a way to solve gies into our everyday objects has discovery and gateway protocols auto-
this integration problem. Web technology created smart environments. Creating matically integrate system components
provides a higher layer of abstraction that the smart artifactsthat constitute these using generic middleware that maintains
hides implementation details from appli- environments requires augmenting their a service definition for each sensor and
cations so that each organization can con- standard functionality to support a new actuator in the space. Programmers
centrate on its own competence and still quality of interaction and behavior. assemble services into composite applica-
leverage the services other research A system-oriented, importunate smart- tions, which third parties can easily imple-
groups provide. ness approach creates an environment that ment or extend.
To test the potential of a Web services gives individual smart artifacts or the envi-
solution, the authors implemented a ronment itself certain self-directed actions
microarray data mining system that uses based on previously collected information. Web-Log-Driven Business
Web services in drug discovery—a For example, a space can be smart by hav- Activity Monitoring
research process that attempts to identify ing and exploiting knowledge about the pp. 61-68
new avenues for developing therapeutic persons and artifacts currently situated Savitha Srinivasan, Vikas Krishna, and
drugs. Although their implementation within its borders. Scott Holmes
focuses on a problem within the life sci- In contrast, a people-oriented, empow-
B
ences, they strongly believe that Web ser- ering smartness approach places the usiness process transformation
vices could be a boon to any research empowering function in the foreground defines a new level of business opti-
field that requires analyzing and mining by assuming that smart spaces make peo- mization that manifests as a range
large volumes of data. ple smarter. This approach empowers of industry-specific initiatives that bring
users to make decisions and take actions processes, people, and information
as mature and responsible people. together to optimize efficiency. For exam-
Socially Aware Computation Although in some cases it might be ple, BPT encompasses lights-out manu-
and Communication more efficient if the system doesn’t ask facturing, targeted treatment solutions,
pp. 33-40 for a user’s feedback and confirmation at real-time risk management, and dynamic
Alex (Sandy) Pentland every step in an action chain, the overall supply chains integrated with variable
design rationale should aim to keep the pricing
M
ost would agree that today’s user in the loop and in control whenever To examine how BPT can optimize an
communication technology possible. organization’s processes, the authors
seems to be at war with human describe a corporate initiative that was
society. Pagers buzz, cell phones interrupt, developed within IBM’s supply chain
and e-mail begs for attention. Technolo- The Gator Tech Smart House: A organization to transform the import
gists have responded with well-meaning Programmable Pervasive Space compliance process that supports the
solutions that ultimately fail because they pp. 50-60 company’s global logistics.
ignore the core problem: Computers are Sumi Helal, Hicham El-Zabadani,
socially ignorant. Youssef Kaddoura, Erwin Jansen,
A research group at MIT is taking the Jeffrey King, and William Mann
first steps toward quantifying social con-
M
text in human communication. These any first-generation pervasive
researchers have developed three socially computing systems lack the abil-
aware platforms that objectively measure ity to evolve as new technologies
several aspects of social context, includ- emerge or as an application domain
ing analyzing the speaker’s tone of voice, matures. Integrating numerous hetero-
facial movement, or gestures.
4 Computer Published by the IEEE Computer Society
@@
L E T T E R S
CONCERNS ABOUT EDUCATION research that lies behind them. No
amount of money could have con-
In “Determining Computing Science’s vinced engineers in the Victorian era to
Role” (The Profession, Dec. 2004, invent television. It took Maxwell’s
pp.128, 126-127), Simone Santini aesthetic dissatisfaction when faced
speaks for many of us who are worried with the asymmetry of the field equa-
about the direction of computer sci- tions to get things started.
ence—and higher education in general. Industry would like to have “ready-
I’m concerned that we are fast cerns should not dictate this measure. to-wear” research—applicable results
approaching a time in this country Steve Rice without the cultural (and often not
when science will be directed by pow- University of Mississippi directly applicable) background—but
erful industry and business objectives [email protected] this is an illusion.
first and foremost, and “pure research”
will become increasingly marginalized. Simone Santini responds: J2EE FRAMEWORK DEVELOPER
I believe this is the end result of a Consumer wishes often don’t convey
capitalist system, where money rules the infallible foresight that industry The article titled “J2EE Development
nearly every activity. This process was would like. In 1920, consumers didn’t Frameworks” (Rod Johnson, IT
given a big push by US President know they wanted radio. In 1975, they Systems Perspectives, Jan. 2005, pp.
Ronald Reagan 20 years ago, and it’s didn’t know they wanted CDs—they 107-110) was well-written and insight-
now accelerating under the Bush were perfectly happy with vinyl. At ful. However, it would have been use-
administration. most, they merely desired better pick- ful to know that the author is also one
Unfortunately, I don’t see any way ups so as not to ruin their records, and of the creators of the Spring frame-
to stop this slide under the present con- they wanted better hi-fisystems to play work.
ditions and cultural climate. them on. The list goes on. This connection does not detract
Jim Williams The problem is that, in many cases, from the article, but it is clearly a rele-
Silver Springs, Md. industry only takes small steps for fear vant piece of information that should
[email protected] of the risks, forgetting that no focus have been disclosed to the reader.
group will ever propose the next major Landon Davies
I enjoyed reading Simone Santini’s ex- step. All you can get from a focus Baltimore, Md.
cellent article in Computer’s December group is advice on how to marginally [email protected]
issue. From working in both academia improve an existing product. This is
and industry for many years, I can add important, of course, but there is more Rod Johnson replies:
the following. to innovation, even to industrial inno- As a former academic, I agree that
Industry is concerned not just with vation than that—academia, as I have it is important to remain impartial with
commercial applicability, but with tried to argue, should have different regard to specific technologies. There-
immediate commercial applicability priorities. fore, I took care to mention alterna-
(their thinking is very short term) in I have nothing against practical tives to Spring when writing this
response to current requests from cus- applications of computing science, of article.
tomers—it’s an easier sale if the cus- course. In fact, I think any mathe-
tomer is already demanding the matician would be happy to know that RETOOLING FOR SUCCESS IN A
product. A breakthrough that has his theorem has improved the bread- KNOWLEDGE-BASED ECONOMY
immediate commercial applicability, to-prosciutto ratio in sandwiches
but is so novel that no customer has worldwide. I am just saying that prac- In “People and Software in a
thought of it and asked for it, is of tical applications can’t be the force that Knowledge-Based Economy” (The
lesser value. drives the discipline. Profession, Jan. 2005, pp. 116, 114-
There is an infinite number of alge- The fact is that Quicksort and rela- 115), Wojciech Cellary uses simple and
bras that can be defined and an infinite tional databases do not spring up elegant service sector taxonomies to
number of algorithms that can be whole like Athena from the head of analyze human roles in a knowledge-
developed, but relational algebra is Zeus. They are part of a process, and based economy. He rightly points out
very helpful and so is Quicksort. the process must proceed by its own that even as the increasing use of com-
All academic pursuits are not equal, internal logic. puters to provide routine intellectual
and there needs to be some measure of It would be an illusion to think that services shrinks the market for humans
the usefulness of one over another. I you can get results that have practical performing these services, humans will
agree that short-term industrial con- applicability without the “pure” continue to excel in areas that involve
6 Computer Published by the IEEE Computer Society
the production of intangible goods and
advanced services.
Although the author anticipates that
robots and automated machines will
prevail in the production of tangible
goods (presumably in the industrial
sector), he does not elaborate on the
impact of automation in the manual
services sectors.
It is particularly interesting to
observe the evolving roles of humans
in manual skill areas that not so long
ago required only moderate intellectual
abilities. For example, modern auto-
mobiles come with complex electroni-
cally controlled subsystems that
REACH HIGHER
require using sophisticated diagnostic
machines for troubleshooting when
they fail. In addition to learning how
to operate these machines, auto
mechanics also must keep up to date
with new technologies so they can rec-
ognize and fix problems, especially as Advancing in the IEEE Computer
additional innovations are incorpo-
rated into newer models. Society can elevate your standing
The proliferation of self-serve sys-
in the profession.
tems has eliminated the need for many
services that humans formerly per-
Application to Senior-grade
formed; instead, the human role now
focuses on providing supervision and membership recognizes
offering assistance if needed. Even
✔
household appliances are becoming ten years or more of
intelligent—vacuum cleaners that can
professional expertise
guide themselves around a room are
now well within the reach of the aver-
Nomination to Fellow-grade
age consumer.
While technology improves human membership recognizes
productivity and frees people from
✔
tedious effort, at times it also has the exemplary accomplishments
effect of eliminating employment
in computer engineering
opportunities. The challenge for those
affected is to retool their skills in ways
that emphasize the same qualities that
GIVE YOUR CAREER A BOOST
would enable them to succeed in intel-
lectual areas, namely creativity, man-
ual expertise, and interpersonal skills. (cid:1)
Badri Lokanathan
UPGRADE YOUR MEMBERSHIP
Atlanta, Ga.
[email protected]
www.computer.org/join/grades.htm
We welcome your letters. Send them to
[email protected].
March 2005 7
A T R A N D O M
Engineers,
current from transistor number 451
was sufficient to meet signaling
requirements to transistors 517 and
Programmers, 669. If it was, the designer would con-
ceptually leave the transistor level and
take the mental elevator that went to
the next floor up: logic.
and Black Boxes At the logic level, the black boxes
had labels like NAND and XOR. The
designer’s objective at this level was to
make sure that the functions selected
correctly expressed the design intent
Bob Colwell from the level above: Should this par-
ticular box be a NAND or an AND?
There were also subfloors. It’s not only
possible, it’s also a very good idea to
niversities teach engineers aggregate sets of boxes to form more
U
all sorts of valuable things. abstract boxes. A set of Dflip-flops is
We’re taught mathemat- routinely aggregated into registers in
ics—especially calculus, synchronous designs, for example.
probability, and statis- Next floor up: the microarchitecture.
tics—all of which are needed to under- At this level, the boxes had names like
stand physics and circuit analysis. We register file, ALU, and bus interface. The
take courses in system design, control designer considered things like band-
theory, electronics, and fields and widths, queuing depths, and through-
waves. But mostly what we’re taught, You can build put without regard for the gates under-
subliminally, is how to think like an lying these functions or the actual flow
and analyze all
engineer. of electrical currents that was such a
Behind most of the classes an engi- concern only a few floors below.
engineered
neer encounters as an undergraduate For hardware engineers, there was
is one overriding paradigm: the black systems by one more floor: the instruction set
box. A black box takes one or more architecture. Most computer engineers
applying the black
inputs, performs some function on never design an ISA during their
them, and produces one output. box paradigm. careers—such is the commercial impor-
It seems simple, but that fundamen- tance of object code compatibility.
tal idea has astonishing power. You can For decades now, the prevailing
build and analyze all engineered sys- theory has been that to incentivize a
tems—and many natural systems, buyer to suffer the pain of mass code
specifically excluding interpersonal MARVELS OF COMPLEXITY conversion or obsolescence, any new
relationships—by applying this para- Modern microprocessors are mar- computational engine that cannot run
digm carefully and repetitively. vels of complexity. Way back when, old code, unchanged, must be at least
Part of the magic is that the function the Intel 4004 had only 2,300 transis- N times faster than anything else avail-
the black box contains can be arbi- tors, a number that is not too large for able. The trouble with this theory is
trarily complex. It can, in fact, be com- smart humans to keep in their heads. that it has never been proven to work.
posed of multiple other functions. And, Engineers knew what each transistor At various times in the past 30 years, N
luckily for us, we can analyze these did and why it had been placed where has arguably reached as high as 5 or
compound functions just as we analyze it was on the die. The bad news was 10 (at equivalent economics) without
their mathematical counterparts. that they hadto know; there were no having been found to be compelling.
As part of an audio signal processing CAD tools back then to help keep The x86 architecture is still king. But
chain, a black box can be as simple as track of them all. the latest contender in the ring is IBM’s
a low-pass filter. As part of a commu- But even then, the black box func- Cell, introduced in February at ISSCC
nications network, it can be a compli- tional decomposition paradigm was 05. Touted as having impressive com-
cated set of thousands of processors, essential. At one level of abstraction, a putational horsepower, Cell is aimed
each with its own local network. designer could ask whether the drive initially at gaming platforms that may
8 Computer Published by the IEEE Computer Society
not be as sensitive to the compatibility seemed like a military boot camp. In Even though EEs may spend 95 per-
burden. fact, it was a boot camp. With the cent of their time in front of a com-
Stay tuned—this new battle should exception of social sciences, humani- puter putting CAD tools through their
play out over the next three years. ties, history, and phys. ed., all of our paces (and most of the other 5 percent
Maybe computer engineers will get to classes were done in exactly this way. swearing at those same tools), they
play out in the sunshine of the top floor I don’t know if we became EEs have an immovable, unforgettable
after all. because we gravitated toward the aca- point of contact with ultimate reality
demic disciplines that seemed most in the back of their minds. Most of the
SOFTWARE FOLKS DO IT TOO natural to us, or if we just learned to decisions they make can be at least par-
The ability to abstract complex things think this way as a by-product of our tially evaluated by how they square
is vital to all of engineering. As with the training. Maybe we just recognized a against natural constraints.
4004’s transistors, without this ability, great paradigm when we saw it and did
engineers would have to mentally retain the obvious by adopting it. CONSTRAINTS ARE GOOD FOR YOU
entire production designs. But the You might think such fixed con-
designs have become so complicated straints would make design more diffi-
that it has been about 25 years since I In general, constraints cult. Indeed, if you were to interview a
last saw a designer who could do that. and boundaries are a design engineer in the middle of a tough
Requiring designers to keep such com- good thing—they focus morning of wrestling with intransigent
plex designs in their heads would limit the mind. design problems, she might well
what is achievable, and doing so isn’t express a desire to throw a constraint
necessary as long as we wield our black- or two out the window. Depending on
box abstractions properly. the particular morning, she might even
In the early days of P6 development Microprocessor design teams also consider jumping out after them.
at Intel, I found it amusing to try to have engineers with computer science In general, though, constraints and
identify various engineers’ back- backgrounds, who may not have gone boundaries are a good thing—they
grounds by the way they thought and through an equivalent boot camp. I focus the mind. I’ve come to believe
argued during meetings. My observa- tried to see if I could spot any of them that hardware engineers benefit
tions went through several phases. by watching for less adroitness in fol- tremendously from their requisite close
I was intrigued to observe that a lowing implicit abstraction-layer ties to nature’s own rules.
group of 10 engineers sitting around a changes in meetings. I thought I saw a On the other hand, the CS folks are
conference room table invariably had few instances of this, but there’s a generally big believers in specifications
a subtle but apparent common mode: countervailing effect: CS majors live and writing down the rules by which
They all used the black-box abstraction and breathe abstraction layers, pre- various modules (black boxes) inter-
implicitly and exclusively, as naturally sumably by dint of their heavy expo- act. They have to be—these “rules” are
as they used arithmetic or consumed sure to programming languages that made up. They could be anything.
diet Coke. Although these engineers demand this skill. Assumptions are not just subtly dan-
came from different engineering When I began pondering the effect gerous here, they simply won’t work—
schools, and their degrees ranged from of black-box function-style thinking the possibility space is too large. It’s not
a BS to an MS or a PhD, they implic- and programming language abstrac- that every choice a hardware engineer
itly accepted that any discussion would tions to see if that might distinguish makes is directly governed by nature
occur in one of two ways—either at between CS- and EE-trained engineers, and thus unambiguous. What func-
one horizontal abstraction layer of the I did see a difference. Good hardware tions go where and how they commu-
design or explicitly across two or more engineers have a visceral sense of nicate at a protocol level are examples
layers. It was generally quite easy to standing on the ground at all times. of choices made in a reasonably large
infer which of those two modes was in They know that in the end, their design space, and there a CS grad’s proclivity
play, and all 10 engineers had no diffi- will succeed or fail based on how well to document is extremely valuable.
culty following mode changes as the they have anticipated nature itself: elec- To be sure, some programmers face
conversation evolved. trons with the same charge they have natural constraints just as real as any
When thinking about this (and yes, carried since the birth of the universe, the hardware designers see. Real-time
I probably should have been paying moving at the same speed they always code and anything that humans can
attention to the technical discussion have, obeying physical laws that gov- perceive—video and audio, for exam-
instead of daydreaming), it occurred to ern electronic and magnetic interac- ple—impose the same kinds of immov-
me that the first two years of my under- tions along wires, and at all times able constraints that a die size limit
graduate EE training had sometimes constrained by thermodynamics. does for a hardware engineer.
March 2005 9
At Random
I’m not looking for black and understanding via the random walk of ment hadn’t actually stated that the
white—I’m just wondering if there are their experiences and education, com- switches were debounced, and the
shades of gray between EE and CS. My bined with extraordinary innate intel- PDP-11 documentation didn’t say that
attempt to discern differences between ligence. Can we teach it? either. I had simply assumed it.
EE and CS grads was simply intended Yale Patt and Sanjay Patel think so. Mechanical switches are constructed
to see if the two camps were distin- It’s a basic tenet of their book, so that flipping the switch causes an
guishable “in the wild”—to see if that Introduction to Computing Systems internal metal plate to quickly move
might lead to any useful insights. (McGraw Hill, 2004). On the inside from one position to a new one where
Computer science is not generally cover, no less a luminary than Donald it now physically touches a stationary
taught relative to natural laws, other Knuth says, “People who are more metal plate. Upon hitting the station-
than math itself, which is arguably a than casually interested in computers ary plate, the moving metal repeatedly
special case. I don’t know if it should should have at least some idea of what bounces up and down until it eventu-
be, or even can be, and it’s not my the underlying hardware is like. ally settles and touches permanently.
intention to pass a value judgment here. Otherwise, the programs they write Even at the glacial clock rates of the
The CS folks, it seems to me, tend to will be pretty weird.” 1970s, the CPU had plenty of time to
be very comfortable in a universe sample a switch’s electrical state during
bounded only by conventions that they the bounces. Debouncing them in soft-
(or programmers like them) have There is a certain ware was just a matter of inserting a
erected in the first place: language intellectual thrill when delay loop between switch transition
restrictions, OS facilities, application you finally break through detection and logical state identification.
architectures, and programming inter- to a new understanding Without an understanding of both
faces. The closest they generally come of something. the hardware and the software, I’d still
to putting one foot down on the be sitting in front of that PDP-11,
ground is when they consider how metaphorically speaking.
their software would run on the hard- There are always tradeoffs. The hor-
ware they are designing—and that Conversely, people who design com- izontally stratified way we teach com-
interface is, at least to some extent, puters without a good idea of how pro- puter systems today makes it difficult
negotiable with the EE denizens on the grams are written, what makes them for students to see how ideas at one
top floor. Absolutes, in the nonnego- easy or hard, and what makes them level map onto problems at another.
tiable natural-law sense of what EEs fail, will in all likelihood conjure up a
deal with, are unusual to them. useless design. I once heard a compiler EVEN GOOD ABSTRACTIONS
The best engineers I have worked expert opine that there’s a special place CAN HURT
with were equally comfortable with in the netherworld for computer If you really want to snow a student
hardware and software, regardless of designers who create a machine before under, try teaching computer system
their educational backgrounds. They they know if a compiler can be written design from application to OS to logic
had somehow achieved a deep enough for it. to circuits to silicon physics as a series
understanding of both fields that they One other data point I’m sure of: of vertical slices.
could sense and adjust to whatever Me. I had taken an OS course and sev- In some ways, I think this problem
world view was currently in play at a eral programming language courses was fundamental to Intel’s failed 432
meeting, without giving up the best and did well at them, but I didn’t chips from the early 1980s—they were
attributes of the alternative view. understand what computer architec- “capability-based” object-oriented sys-
There is a certain intellectual thrill ture really meant until I had to write tems in which one global, overriding
when you finally break through to a assembly code for a PDP-11. My pro- paradigm was present. The system was
new understanding of something, be it gram had to read the front panel designed from one point of view, and
physics or engineering or math—or switches, do a computation on them, to understand it you had to adopt that
poetry analysis, for that matter. I and display the results on the front point of view. To wit: Everything—and
always felt that same thrill when I saw panel lights. I do mean everything—was an object
someone blithely displaying this kind My first program didn’t work reli- in those systems. In some ways, it was
of intellectual virtuosity. ably, and I spent hours staring at the the ultimate attempt to systematically
code, line by line, trying to identify the apply the black-box paradigm to an
BOTTOMS UP AND TOPS DOWN conceptual bug. I couldn’t find it. I entire computer system.
The engineers I know who routinely finally went back to the lab and stared An object in a 432 system was an
do this intellectual magic somehow instead at the machine. Eureka! It sud- abstract entity with intrinsic capabili-
arrived at their profound level of denly occurred to me that the assign- ties and extrinsic features. Every object
10 Computer