El Futuro Del Pc

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The Future of the PC106 Scientific American: The Solid-State Century

“I think there is a world market for maybe five computers.” — Thomas J. Watson, IBM chairman, 1943

P rediction is fraught with peril. The sudden ar-rival in our culture of tens of millions of per-sonal computers, however, necessarily makes

one ponder what the near future will bring. Although thepersonal computer lets users perform many different use-ful or entertaining tasks, such as writing letters, playinggames, sending e-mail or surfing the World Wide Web, itmay already be—in its current incarnation—in its last days.

Rather than interact solely with a personal computer,users will engage a “personal network,” which is alreadyevolving from today’s personal computer and its relateddevices. The current PC’s capabilities barely scratch thesurface of what the future may have in store. Thechangeover could be well along within a decade.

The typical personal network (PN) will consist of oneor more computing devices in communication with one

another, via a mix of permanent and transient communi-cations links. At least one of the devices in a PN will berecognizable as a descendant of today’s ubiquitous PC.Resembling current high-end laptops, this device will bethe primary portal by which the user will access the net-work. (The portal will also function as a conventional PCwhen it is disconnected from the rest of the PN.)

In fact, rudimentary PNs already exist. Recently one of us (Friedlander) was working at home and had two lap-top computers and a desktop computer linked togetherin a tiny local-area network (LAN). I was using two of the machines while moving information to them from thethird. My wife happened by during this episode. She

watched for a moment and then asked if I knew how sil-

ly the whole scene looked. I had to admit that I did. Yetthat little contretemps made me realize that the PN al-ready exists, albeit flimsily.

All the connections of my little network were out in theopen, but tomorrow’s fully realized PN will be transpar-ent, as invisible to the user as the networks that provideelectricity to every outlet in the home. And, for the mostpart, the network will require hardly any intervention tooperate.

Whereas the advent and success of the PC can be legit-imately classified as a revolution, the PN will be the prod-uct of evolution. PNs will use the same basic architecturethat computers have employed since the days of Thomas

J. Watson’s slightly flawed prediction. That architecture,like the architecture of PCs now, will consist of a centralprocessing unit (CPU), memory and input/output (I/O)devices. The CPU (for example, a Motorola PowerPC chipor an Intel Pentium II) does the brainwork, manipulatingdata. Memory, which includes random-access memory,

or RAM, stores the information, such as the data that theCPU is currently using. Meanwhile the I/O devices literal-ly do just that, providing the means for information toflow into and out of the computer. Typical I/O devices in-clude those designed for interaction, such as the key-board, screen and mouse; those involved with storage—

for example, disks and CD-ROMs (compact disc, read-only memory); and those that serve as communicationsdevices (modems and Ethernet LAN cards).

In the conventional PC, the CPU, memory and I/O de-vices are connected via one or more buses, circuits thatprovide the communications link making it possible forthe various components of the PC to share data.

In the PN, the network itself is, in effect, the bus: thenetwork architecture implies data flow in any and all di-rections, with the individual computers fully aware of thenetwork and its constituents. Like the members of abaseball team interacting to make a play, member devicesin the network will often work together. Just as playerscome to bat individually, however, each network memberwill operate some of the time without linking to other de-vices in the network.

Some of these individual devices within the PN will bededicated to you, its owner, whereas others will be sharedwith other users, via their PNs. Again, the primary meansfor you to access the PN will be a portable computer re-

sembling a high-end laptop. This unit will be dedicated to

THE FUTURE OF THE PCby Brad Friedlander and Martyn Roetter

An item that looks like one of today’s

laptops will be a portal into a personal network

with phenomenal organizational skills

Copyright 1997 Scientific American, Inc.



D A V I D S U T E R

PERSONAL NETWORK will rely on excep-tionally user-friendly interfaces to increase theindividual’s ability to assimilate and dispatch in-formation quickly and easily. The networks of people, businesses, government agencies andother entities will seamlessly interact. If thedaunting technical challenges can be met, the re-sult for the user will be unparalleled control overhis or her daily environment.





you. Other parts of the network couldinclude computing devices embedded inyour home, in your appliances or inyour car. Because other family memberswill no doubt have their own PNs, someof these individual devices could be partof multiple PNs. Various servers, whichare relatively powerful computers thatanchor the network by performing com-putationally intensive services for lesspowerful computers on the network, willmanage the PNs and their data stores.

These servers will be shared among anumber of PNs, but the individual PNswill remain logically separated.

One of the qualities of the PN thatwill make it so versatile will be its dy-namic and seamless linking to the PNsof family members, friends or groupswith a common interest, as well as toshared environments, such as the homeor office. A combination of wire-basedand wireless communications will makeit possible to establish links to otherPNs anywhere in the world, whenever

you need to.

A Day in the Life

So much, for now, for the skeletal de-tails of the personal network. A sce-

nario describing a network in action il-lustrates its power and attraction. Imag-ine a Wednesday morning in the autumnof 2007. You awake to the sounds of your favorite music, playing at 7:00A.M., a full half-hour later than usual.Your personal network has let you sleep

late, based on your appointment calen-

dar for the day. During your last mo-ments of sleep, the PN collected infor-mation from various news outlets, as-signing them priorities based on per-sonal-interest profiles you had created.It turned up the temperature in part of your home (waiting that extra half anhour today) and instructed your cof-feemaker to brew up a fresh pot.

When you sat down to drink your firstcup of coffee, a thin but meaty morningnewspaper was hot off your printer,

specifically tailored to appeal to yourconcerns. Via voice communication anda large, flat-screen display, your PNnotifies you that one of its computingdevices has failed. Not to worry, how-ever: the network has alreadysubmitted a repair order, and,by the way, no data werelost, thanks to automaticbackups in other net-work devices. You couldread the paper on thedisplay, but you still

prefer to actually holdit in your hands. Asyou check last night’sbox scores for the twoteams you follow, the PNreminds you that your wifeis away on business. “Yes,”you respond as you continue toread and sip, “I noticed as soon as Iwoke up.” The PN ignores your flip-pant tone to further remind you thatshe will be flying home tonight.

Shortly before it is time to leave for

work, your PN starts to replicate infor-

mation onto your laptop. This includesitems stored on a server within yourPN, such as the newspaper, your calen-dar and the documents that you revisedsince arriving home last night. In con-trast to today’s laptop, which houses allyour data, the PN laptop carries onlycopies of data from servers on your PNand on your office and other networks.Thus, the data are decentralized andcan be updated whenever necessary.This structure is part of what provides

the ability to recover information fullyand easily when a single computing de-vice fails.

As you check your tie in the mirror,the PN notifies the navigation comput-

er in your car of your departuretime and destination this

morning. The networkswitches the laptop overto sleep mode to con-serve battery life and toallow you to discon-nect it from its link. As

you leave the house,the car engine roars tolife. Your vocal com-

mand unlocks the door.

EARLY INFORMATION PROCESSORS were large and oftendifficult to use. IBM’s seminal 701 computer took up a wholeroom (left ); the “electro-artograph,” an early facsimile machine,could work only with a photographic negative, which was en-

graved at the receiving end. Tomorrow’s personal computers willalso span enormous spaces, but in virtual fashion. High-speedprocessors, advanced software and wireless communications willcome together to make connections transparent.

I B M

D A V I D S U T E R

IT KNOWS WHEN YOU’REAWAKE and many other aspects

about your private life. Moreover, itwill convey that information only to thosewho need it and who have permission tohave it. Encryption technology will keeppersonal information hidden from thoseoutside the individual’s sphere of sanc-

tioned interactions.

S C I E N T I F I C A M E R I C A N




As you back out of the driveway, thenavigation computer gets wind of atraffic snarl, informs you and offers analternate route, estimates your new ar-rival time, notifies your office staff of your situation and reschedules your ear-ly meetings.

When you arrive at the office, yourPN, via the laptop, synchronizes with

the office network, bringing relevantitems, such as those documents you re-vised last night, up to date. As you set-tle in at your desk, your PN links withyour wife’s PN to get her arrival sched-ule and to make a dinner reservation ather favorite restaurant. (You’ll still getpoints for being so thoughtful.)

The day passes, highlighted by a vid-eo teleconference and a few old-fash-ioned telephone calls and meetings. Asyou prepare to leave work, your PNreplicates the information you need totake home, synchronizes calendars andlearns that your wife’s flight is one hourlate. It reschedules the dinner reserva-tion and notifies your car, and yourevening begins.

Getting There from Here

Although many activities in this imag-inary day are achievable now, the

protagonist would need to be a highlyskilled computer user and would haveto interact frequently, if not constantly,with each computer in the PN to make

this scenario work. Furthermore, theequipment would cost a small fortune.All these factors should rapidly change.

Other examples of nascent PNs al-ready in existence go a bit further thanthe three computers in the living roomillustration. Many people have palmtopdevices, such as the U.S. Robotics Pilot,and synchronize data between these andtheir laptop or desktop. Mobile usersfrequently connect into a LAN at workto exchange information with otherpeople and to copy any changed files

from their laptop to the office desktop.And some homes already have LANsthat include both personal and sharedresources—separate computers for eachparent and child with printers andscanners that can be used by anyone onthe network.

For the type of sophisticated networkdescribed in our workday setting tocome into being, however, various tech-nological hurdles still need to be cleared.Certainly, processing power must con-tinue to improve dramatically and the

cost of that power must continue to fall.

But these improvements are among thelowest of the hurdles.

One of the most critical missing piec-es of technology is the user interface.The PN will have to interact with peoplein ways that we humans find natural,so as to be attractive to those who mayhave far fewer computer skills than con-temporary users do. The voice identifi-

cation in our scenario is a prime exam-ple of the coming changes, as are speechrecognition and speech synthesis by thecomputer. Users should ultimately beable to interact with their PNs simplyby talking and listening to them. (Re-member how the crew of the Enterprisespoke with the shipboard computer onStar Trek?)

Enabling machines to understand usenough of the time to be useful still rep-resents a formidable challenge. CaptainKirk sounds quite different from Scotty.Speech patterns may even vary for asingle person, depending on his or hermood or physical health. Nevertheless,systems already exist that allow userssome vocal control of PCs, including en-try of data, text and commands. The ac-tive vocabulary can reach tens of thou-sands of words. Depending on aural ap-titude, the prices for these systems rangefrom about $100 to as high as $1,500.

Speech recognition is based on identi-fication of phonemes, the smallest acous-tical components of language. (SpokenEnglish includes roughly 80 phonemes.)

Human speech is sampled by the com-puter, with the digitized audio signalscompared with those on file. Some lee-

way must be available to accommodatevariations in individuals’ pitches andword duration. In addition, the proba-bility of a particular word followinganother will clue in the computer to thelikelihood of a match.

Machine-to-Machine Bonding

In addition to communication betweenhuman and machine, the machinesmust be able to talk to one another reli-ably, especially if the PN is to have thecapability to interact easily with otherpeople’s PNs. Means of communicationinclude physical links between machines,such as in home LANs; infrared linksamong collocated devices in very closeproximity; short-range radio links, as incordless phones; long-range radio links,as in cellular phones; and cable or high-speed connections to the rest of theworld. Both wired and wireless com-munications require improvement forthe PN to become a reality.

Wireless communications techniquesare clearly central to PN mobile comput-ing. Users must be able to transmit andaccess information regardless of their orits location and without a physical con-nection. For in-room communication,infrared systems can already providelinks of up to four megabits per second(Mbps) over distances of about one me-ter. Wide-area usage requires radio links.

The challenges of wireless communi-

cations are far greater than those posedby wired links, whether copper or fiber-optic cables. Basic communication pa-

The Future of the PC Scientific American: The Solid-State Century 109

1980 1990

YEAR

2000

C O S T O F A M I L L I O N I N S T

R U C T I O N S P E R S E C O N D

( D O L L A R S )

MI L L I ON S OF I N S T R U

C T I ON S P E R S E C ON D

400

300

200

100

0

500

600

700

800

900

1,000

1,10010,000

1,000

100

10

1

0.10

SOURCES: Intel; Semico Research Corporation

INCREASES IN PROCESSING SPEED and decreases in costs for those ever higher

speeds will be major factors that allow the development of personal networks.

J A R E D S C H N E I D M A N D E S I G N




rameters, such as transmission speed, er-ror rate, reliability and delay, can changesubstantially and suddenly during thecourse of a single wireless communica-tion. Such instability is rooted in thevariability of radio-frequency noise andin the signal attenuation that can arisefrom natural sources, such as storms, orinterference from various electronic de-

vices. Mobility throws yet more un-knowns into the equation. For example,radio-wave propagation can be suddenlyinterrupted when a building, vehicle orsome other large object comes betweenthe transmitting and receiving devices.Even the presence or absence of foliagemay affect transmissions, causing sea-sonal variations in performance.

For these and other reasons, the trans-mission speeds available in wirelesscommunications tend to be much slow-er than those over wired links. The im-plications of these limitations and char-acteristics of wireless communicationsfor software are considerable. Whilereading, you may be momentarily dis-tracted by the sound of a car alarm, butyou have no trouble returning to yourplace and the flow of information. Ap-plications that are expected to functioneffectively in an environment involvingwireless channels must likewise be ableto handle variable communications per-formance and recover from unexpectedbut inevitable interruptions, keeping

track of partial or incomplete results.Despite these disadvantages, the great

utility of wireless data communicationshas kept interest high. Among the op-tions now being considered or developedare the use of existing cellular telephonechannels for data, as well as dedicatedwireless data systems. Effective wirelessdata-transmission speeds (up to 10,000

bits per second) are significantly slowerthan modems over dial-up wired tele-phone lines (up to 33,600 bits per sec-ond). Data speeds over modern digitalcellular systems, however, such as theEuropean GSM (Global System for Mo-bile Communications), are beginning toreach these higher levels.

Wireless data speeds currently lag wellbehind those of various modern data ser-vices that users can obtain from phonecompanies, such as so-called frame relaylines or the Integrated Services DigitalNetwork (ISDN). Both can offer rates inthe megabits-per-second range. But thenext generation of mobile wireless com-munications systems, known as IMT2000 (International Mobile Telecom-munications), is aiming at speeds of upto two million bits per second. As thename implies, IMT 2000 is being devel-oped by the international telecommuni-cations community for introduction atthe turn of the century.

Longer-term research and develop-ment efforts are being directed toward

what is known as wireless asynchronoustransfer mode (ATM) to reach rates of 155 million bits per second or even high-er. This system has the further advantageof compatibility with the anticipatedspread of ATM-based services in wiredtelecommunications. And although to-day’s mobile wireless services transmitat frequencies of 800 to 900 megahertz

and two gigahertz, the Federal Com-munications Commission has designat-ed frequencies in the tens of gigahertzrange for future use as the lower fre-quencies become crowded.

In anticipation of this bandwidthavailability, high-speed satellite servicesare already being planned for shortlyafter 2000. One key project is the Tele-desic multisatellite array, using severalhundred satellites in low-earth orbits.Boeing, Microsoft founder Bill Gatesand cellular-telephone business tycoonCraig McCaw are all investing in thistechnology. The Teledesic array willdownlink at 18 gigahertz and uplink at28 gigahertz. It therefore should be ableto provide coverage at up to gigabit-per-second speeds even in the most remoteparts of the globe. Stanley would be ableto call Dr. Livingstone, who could thensend a digital map image directly toStanley’s laptop. (“High data-rate satel-lite link, I presume?”)

Having all these data flying aroundnecessarily raises privacy issues. Onewants to ensure that the PN follows or-

ders solely from its owner and thattransmissions reach only those peopleor devices one wants to reach (as NewtGingrich, Prince Charles and other no-tables recently discovered, when theirsupposedly private cellular phone con-versations became newspaper head-lines). In other words, the personal net-work must be secure.

Open, Says Me

Access to PN devices will be gov-

erned by biometrics, which is theuse of physiological features, such asthe pattern of a voice, fingerprint oriris, to permit activation (for example,voice recognition allows you and onlyyou to enter your car). Classic controls,such as passwords, will also supple-ment biometrics.

The core of security, however, will bepublic-key cryptography, a mathemati-cally based system that will be used tosecure owner control over the PN andallow for privacy both within the net-

work and when linking with other net-


RADIO TRANSMITTERS inconspicuously placed on light poles a quarter mile aparthave already established a wireless communications network over sections of Seattle,San Francisco and Washington, D.C. A wireless modem in communication with thesedevices, which in turn interface with wired access points, enables users of the network

(built by Metricom) to access information far from telephone lines.

R I C O C H E T / M E T R I C O M ,

I N C .




works. (The encryption systems knownas RSA and PGP are examples of pub-lic-key cryptography.)

Public-key cryptography works byassigning each person two different keys,which are actually two related numbers.Both keys are many digits in length andwould be impossible for most people tomemorize. They are typically stored on

your computer’s hard drive or on a disk.The public key is available to anyonewho wants to send you a secure message.The private key, however, is known onlyto you. As the name implies, public-keycryptography can ensure encryption andtherefore privacy. A sender encrypts amessage to you—say, a credit-card num-ber—using your public key. The messagecan be deciphered, however, only withboth the public and the private key—

and only you have the latter.Another critical technology is soft-

ware. Programs will have to make senseto multiple computers and operatingsystems. Software will no doubt be writ-ten in a language (like Java) that cantranslate commands into readable in-structions for whatever device needsthem. In our scenario, the news collec-tion was made possible by programsrunning on the various news servers.

Big Challenge: Juice

Perhaps the greatest challenge to thecreation of the PN, as it is for the

electric car or even for your portablecompact-disc player, is also one of themost seemingly mundane ones: build-ing better batteries. Long-lasting andflexible batteries will allow the devicesin the PN to continue to function with-out a constant incoming energy supply.Systems known as uninterruptible pow-er supplies will also protect critical com-ponents of the PN in case of a power

loss. Backup batteries will provide pow-er for the minutes necessary to save alldata and shut the system down cleanly.When power is again available, the net-work’s components would be cued torestart automatically.

Among the most significant improve-ments in batteries are the use of creativepackaging techniques to enhance ener-gy density, along with the introductionof lithium ion technology. Lithium of-fers higher energy densities than earlier

rechargeable technologies—nickel cad-mium (NiCd) and nickel metal hydride(NiMH) [see illustration above].

As long as technology continues toevolve along current capability and costcurves, the personal network shouldexist at a price comparable to that of today’s high-end PCs. Although we seeno insurmountable barriers, two majornontechnical stumbling blocks exist.

First, users will need to believe that thebenefits of the personal network exceedthe potential for failures, which woulddisrupt usage, and for misuse or expo-sure of personal information. The sec-ond is the willingness of hardware, soft-ware and network vendors to cooperatein defining and implementing the stan-dards necessary for the seamless inte-gration we envision.

Should these problems be overcome,the worldwide interplay of personal net-

works could create a global network,which would bring all of us closer to-gether. The so-called six degrees of sep-aration, which says that every personon the earth is only six acquaintancesaway from any other person, may stillrule. But the time and effort required totraverse those six degrees would vanish.Such a world could be a very interest-ing place indeed.

The Future of the PC Scientific American: The Solid-State Century 111

BRAD FRIEDLANDER and MARTYN ROETTER are bothprincipals in the management and technology consulting firmArthur D. Little, based in Cambridge, Mass. Friedlander helps thefirm’s customers worldwide make effective use of information tech-

nology. Roetter currently focuses on assisting network operatorsand their equipment suppliers as they apply new broadband trans-mission and switching technologies and network architectures todeploy new services to their customers.

Being Digital. Nicholas Negroponte. Alfred A. Knopf, 1995.Computers. Egil Juliussen in IEEE Spectrum, Vol. 34, No. 1,pages 49–54; January 1997.

The PC of the Future. Special issue of PC Magazine, Vol. 16,

No. 6; March 25, 1997.What Will Be: How the New World of Information Will

Change Our Lives. Michael Dertouzos. HarperSanFrancisco(HarperCollins), 1997.

Further Reading

The Authors

SEALING

COMPOUNDNEGATIVE

ELECTRODE

SOLID

POLYMER

ELECTROLYTE

NEGATIVE

CURRENT COLLECTOR

CARRIERNEGATIVE

TERMINAL

POSITIVE

TERMINAL

POSITIVE

CURRENT

COLLECTOR

POSITIVE

ELECTRODE

LITHIUM POWER SOURCE, often called a chewing gum cell, is one of the mostpromising recent developments in mobile power sources. The battery is flat and flexi- ble, like a stick of chewing gum (one of its manufacturers refers to its product as a film battery because its batteries are also reminiscent of film frames). These batteries, whichcould soon be as thin as 0.2 millimeter, can be manufactured in long, continuous strips,which should reduce production costs. Both NiCd and NiMH cells can also be pro-duced using the chewing gum format.

SA

J A R E D S C H N E I D M A N D E S I G N


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