Que upgrading and repairing laptops 2nd edition dec 2005 ISBN 0789733765

Laptop computers are the largest growing part of the computerindustry, with sales that continue to outpace desktop systems.For those in the industry, there has never been a better reason

By Scott Mueller

Publisher: Que Pub Date: December 16, 2005 Print ISBN-10: 0-7897-3376-5 Print ISBN-13: 978-0-7897-3376-4 Pages: 912

or how to live on the road with it, this is the one must-have book of the year!

By Scott Mueller

Publisher: Que Pub Date: December 16, 2005 Print ISBN-10: 0-7897-3376-5 Print ISBN-13: 978-0-7897-3376-4 Pages: 912

Upgrading and Repairing Laptops, 2nd Edition

Copyright © 2006 by Que Corporation

All rights reserved No part of this book shall be reproduced,stored in a retrieval system, or transmitted by any means,

electronic, mechanical, photocopying, recording, or otherwise,without written permission from the publisher No patent

liability is assumed with respect to the use of the informationcontained herein Although every precaution has been taken inthe preparation of this book, the publisher and author assume

no responsibility for errors or omissions Nor is any liabilityassumed for damages resulting from the use of the informationcontained herein

as affecting the validity of any trademark or service mark

Every effort has been made to make this book as complete and

as accurate as possible, but no warranty or fitness is implied.The information provided is on an "as is" basis The author andthe publisher shall have neither liability nor responsibility to anyperson or entity with respect to any loss or damages arisingfrom the information contained in this book or from the use ofthe CD or programs accompanying it

Bulk Sales

Que Publishing offers excellent discounts on this book whenordered in quantity for bulk purchases or special sales For

Scott Mueller is president of Mueller Technical Research (MTR),

an international research and corporate training firm Since

1982, MTR has produced the industry's most in-depth, accurate,and effective seminars, books, articles, videos, and FAQs

covering PC hardware and data recovery MTR maintains a clientlist that includes Fortune 500 companies, the U.S governmentand foreign governments, major software and hardware

Although he has taught classes virtually nonstop since 1982,Scott is best known as the author of the longest running, mostpopular, and most comprehensive PC hardware book in the

world, Upgrading and Repairing PCs, which has not only been

produced in more than 15 editions, but has also become thecore of an entire series of books

Scott has been featured in Forbes magazine and has written several articles for Maximum PC magazine, several newsletters, and the Upgrading and Repairing PCs website.

If you have suggestions for the next version of this book, any

www.upgradingandrepairingpcs.com and click the Ask Scottbutton

When he is not working on PC-related books or on the roadteaching seminars, Scott can usually be found in the garageworking on several projects He is currently working on a

custom 1999 Harley-Davidson FLHRCI Road King Classic and amodified 1998 5.9L (360ci) Grand Cherokeea hot rod 4x4

been inspiring

Thanks to Lisa Carlson of Mueller Technical Research for helpingwith product research and office management She has

fantastic organizational skills that have been a tremendous help

in managing all the information that comes into and goes out ofthis office

I'd like to thank Todd Brakke for doing the editing for this

project His excellent tips and suggestions really help to keepthe material concise and up to date I'd also like to thank

Charlotte Clapp, Tonya Simpson, and Chuck Hutchinson, whoalso worked on the editing for this book, as well as all the

illustrators, designers, and technicians at Que who worked sohard to complete the finished product and get this book out thedoor! The people at Que are a wonderful team that producesclearly the best computer books on the market I am happy andproud to be closely associated with Que

Finally, I would like to thank the thousands of people who haveattended my seminars; you might not realize how much I learnfrom each of you and all your questions!

Many of my all-night writing raves are fueled by a variety ofpossibly less-than-nutritious (but very tasty and loaded withenergy) food and beverages In particular, this edition was

fueled by bags and bags of Starbucks coffee processed via akiller Capresso automatic coffee/espresso machine (utter

nirvana for an addicted coffee drinker like me), many cases ofCoke Classic (no Pepsi allowedgotta have the burn!), Red Bulland AMP energy drinks, and cases of Trolli Brite Crawler Eggsand Pearson's Salted Nut Rolls For special occasions when Ireally needed a boost, I enjoyed a couple bottles of Skeleteen'sBrain Wash, the ultimate energy drink Why, that covers thethree major workaholic nerd/geek food groups right there:

caffeine, sugar, and salt!

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what we're doing right, what we could do better, what areasyou'd like to see us publish in, and any other words of wisdomyou're willing to pass our way

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Welcome to Upgrading and Repairing Laptops, the only book of

its kind on the market!

Laptop computers are the largest growing part of the computerindustry, with sales that continue to outpace desktop systems.For those in the industry, there has never been a better reason

to get into upgrading and repairing laptops, because not onlyare they selling better than ever, but their higher prices allowyou to charge more for services rendered

But aren't laptops proprietary, which means they cannot easily

be upgraded or repaired? Many people are familiar with the factthat desktop PCs normally use industry-standard components,which allow cost-effective upgrades and repairs to be

subject in more depth, resulting in this book

In this book, you will learn about all the components that make

up a modern laptop or notebook computer, which componentsare based on industry standards and which are proprietary, andwhich components can easily be upgraded or replaced As most

of you know, laptops are more expensive than desktops, so

whereas desktop computers are becoming more and more of acommodity, laptops are still somewhat exclusive They are more

You can look at this book two ways: From the perspective of alaptop user, knowing how to upgrade and repair your own

system can save you a bundle of money! Using the information

in this book, you can effectively troubleshoot a problem; isolatethe defective component; obtain a replacement; and finally

perform the physical interchange of parts, the actual upgrade,

or repair This capability is useful not only for older systems,where the cost of service might exceed the value of the system,but also with newer laptops, which can be easily upgraded withnewer technology such as wireless networking, faster USB orFireWire ports, more memory, larger hard disks, and even

faster processors

From the perspective of a computer technician or support

person working in the industry, knowing how to upgrade andrepair laptop computers gives you a significant edge over others

in the industry who are afraid to open laptop systems They can

be daunting Many of the laptops on the market today are heldtogether by upwards of 100 screws, often consisting of severaldifferent types! They also often include many intricately

assembled plastic parts that can easily break or be damaged ifyou don't take them apart properly The benefit is that as a

repair technician, you can charge more for laptop service andrepair, which gives you another edge over other technicians whocan work only on commodity-level desktop systems

I initially struggled with the terms laptop and notebook before

even beginning work on this book, not only with how to usethem in the content but especially with the title Although it wasnot necessarily true in the beginning, in the current context ofthe industry, these terms are used interchangeably to describesystems The truth is, there is no consistent industry-wide

definition of what is a laptop computer and what is a notebookcomputer

Originally, there was some unofficial size differentiation betweenwhat was considered a laptop versus what was considered a

notebook (the term notebook was used to describe an

arbitrarily smaller version of a laptop) However, more recentlythat distinction has completely disappeared Standardization onscreen technology, screen sizes, as well as keyboard/pointingdevice layout and size have all served to muddy and eventuallydissolve any differences between what was once considered alaptop and what was considered a notebook The fact that

virtually all modern portables include 13-inch (diagonal) or

larger screens (which is why innovations such as the ThinkPad

701 "butterfly" collapsible keyboard aren't used anymore) aswell as industry-standard keyboard layouts, integrating a

pointing device and palm rest, has served to greatly equalizethe sizes of such systems There are still differences in weightand thickness between various makes and models, but in

general, modern laptop/notebook systems, from the least to themost powerful and expensive, come in very similar sizes

So what do we call these systems now? Are they laptops or

notebooks? Virtually all manufacturers now use the term

notebook to describe all their portable systems, from huge

desktop replacements down to ultra-slim or ultra-light models.Unfortunately, outside the advertising and marketing world, few

people seem to use the term notebook Perhaps that is because

to something other than a computer, and thus be easily

misunderstood You almost have to say "notebook computer"for it to become clear what you mean On the other hand, if yousay "laptop," most people immediately know that you mean

I wrote this book for people who want to upgrade, repair,

maintain, and troubleshoot laptop computers, as well as forthose enthusiasts who want to know more about laptops orportable PC hardware in general This book covers the full

gamut of laptop and portable PCs, from the oldest to the latest

in high-end multi-gigahertz mobile workstations If you need toknow about everything from the original Compaq Portable PC tothe latest in PC technology on the market today, this book andthe accompanying information-packed DVD-ROM are definitelyfor you

This book covers state-of-the-art mobile hardware and

accessories that make modern mobile computers easier, faster,and more productive to use Inside these pages you will find in-depth coverage of every mobile processor, from the original386SL to the latest Mobile Pentium 4, Pentium M, and MobileAthlon XP-M

Upgrading and Repairing Laptops also doesn't ignore the less

glamorous PC components Every part of your mobile systemplays a critical role in its stability and performance Over thecourse of these pages, you'll find out exactly why your

motherboard's chipset might just be the most important part ofyour laptop as well as what can go wrong when your processorruns too hot You'll also find in-depth coverage of technologiessuch as DDR SDRAM, graphics, audio, AGP, Mini PCI, LCD

displays, recordable CD and DVD drives, USB 2.0, FireWire, andhigh-capacity external or removable storageit's all in here!

Chapter-by-Chapter Breakdown

This book is organized into chapters that cover the components

laptop/notebook systems A few chapters serve to introduce orexpand in an area not specifically component related, but mostparts in a laptop have a dedicated chapter or section, which willaid you in finding the information you want

The first two chapters of this book serve primarily as an

introduction Chapter 1, "Portable Systems Background," beginswith an introduction to the development of portable computers.This chapter incorporates some of the historical events that led

provide a step-by-step process showing how to completely

disassemble and reassemble a typical laptop The drawings

included in this chapter, as well as the video included on theDVD-ROM, will greatly aid you in understanding these

procedures

Chapter 4, "Processors," includes detailed coverage of Intel'smobile Pentium M (part of Centrino mobile technology), mobilePentium 4 and Pentium 4-M, mobile Pentium III, mobile

Pentium II, mobile Celeron, and earlier central processing unit(CPU) chips There's also detailed coverage of AMD's line ofhigh-performance mobile Athlon XP-M and Sempron processors

as well as older mobile Athlon and mobile Duron processors.Because the processor is one of the most important parts of alaptop PC, this book features extensive mobile processor

coverage, more than you'll find in any other book All the

unique form factors used in mobile processors are discussed,with diagrams, drawings, and examples This information isinvaluable in understanding how processors are implemented in

Chapter 5, "Motherboards," covers the motherboard, mobilechipsets, motherboard components, and primary system buses

in detail A chipset can either make a good processor better orchoke the life out of an otherwise high-speed CPU I cover thelatest chipsets for current mobile processor families, includingmobile chipsets from Intel, AMD, VIA, and more This chapteralso covers special bus architectures and devices, such as high-speed Peripheral Component Interconnect (PCI), including MiniPCI and PCI Express Plug and Play (including Universal PnP)configuration of resources and ways to handle resource conflictsare also discussed

Chapter 6, "Memory," provides a detailed discussion of laptopmemory, including the latest memory specifications After theprocessor and chipset, the system memory is one of the mostimportant parts of a laptop or mobile computer It's also one ofthe most difficult things to understandit is somewhat intangible,and how it works is not always obvious If you're confused

about the difference between system memory and cache

memory; SODIMMs and Micro-DIMMs; SDRAM versus DDR

SDRAM; EDO versus PC133 versus PC3200, this is the chapterthat can answer your questions

Chapter 7, "Power," is a detailed investigation of laptop batterytechnology, as well as AC adapters and power-managementschemes

Chapter 8, "Expansion Card Buses," covers the ExpressCard, PCCard, and CardBus interfaces, otherwise sometimes called

PCMCIA slots Also covered are newer technologies such as USB

2.0 and FireWire (IEEE 1394/i.LINK), as well as older legacyserial and parallel ports Due to the limited space in laptop

computers, external USB 2.0 and FireWire devices offer a widerange of expansion capability

Chapter 9, "Hard Disk Storage," covers the smaller 2.5-inch

memory-storage devices, such as CompactFlash, SmartMedia,MultiMediaCard, SecureDigital, Memory Stick, xD-Picture Card,and USB "keychain" drives Finally, this chapter covers magneticremovable storage, such as standard floppy and magnetic tapedrives

Chapter 11, "Graphics and Sound," covers everything there is toknow about video chipsets and display technology, as well asthe various interface standards for external displays This

chapter also covers sound and sound-related devices, includinginternal and external sound "boards" and speaker systems

Chapter 12, "Communications," covers all aspects of

connectivity, including everything from dial-up using modems,

to both wired and wireless networking An emphasis on wirelessstandards is designed to feature one of the best new

technologies coming to mobile systems: 802.11a/b/g

networking (otherwise known as Wi-Fi)

Chapter 13, "Keyboards and Pointing Devices," covers

keyboards, pointing devices, and other input devices used tocommunicate with a laptop, including external wireless miceand keyboards

Chapter 14, "Portable System Accessories," covers all the

Chapter 15, "Software and Operating Systems," covers the

Windows versions used on laptops, including detail on the bootsequence, configuration options, as well as installation and

configuration procedures

Chapter 16, "Problem Solving and Troubleshooting," coversdiagnostic and testing tools and procedures This chapter

includes information on general troubleshooting and problemdetermination Here, I show you what prepared laptop

technicians have in their toolkits, including a few tools you

might have never seen or used before

Finally, Chapter 17, "Portable Resource Guide," covers

manufacturer, vendor, and alternative resources that are usefulfor upgrading, repairing, maintaining, and troubleshooting

laptops This information can be especially useful if you have aproblem while on the road

The Upgrading and Repairing Laptops DVD

I've included a DVD-ROM with the book that contains all-new,studio-quality, full-screen video, showing laptop construction,components, and disassembly! Also, on the disc you'll find adetailed vendor database This custom database contains

hundreds of entries of contact information for the industry'sleading manufacturers and vendors It's like having my Rolodex

on your computer This database is fully searchable and

printable

Scott's Website

Don't miss my book website at

monthly book updates I use this spot to keep you updated

throughout the year on major changes in the PC hardware

industry Each month, I write new articles covering new

technologies released after this book was printed These articlesare archived so you can refer to them anytime

I believe this book is absolutely the best book of its kind on themarket, and that is due in large part to the extensive feedback Ihave received from both my seminar attendees and book

readers I am so grateful to everyone who has helped me withall my books I have had personal contact with many thousands

of you via emails you have sent me, as well as through the

seminars I have been teaching since 1982, and I enjoy yourcomments and even your criticisms Using this book in a

teaching environment has been a major factor in its

development Your comments, suggestions, and support havehelped me to write the best PC hardware books on the market

I look forward to hearing your comments after you see this

book

Scott

Portables, like their desktop counterparts, have evolved a great

deal since the days when the word portable could refer to a

desktop-sized system with a handle on it Today, much smallerportable systems can rival the performance of their desktopcounterparts in nearly every way Many portables are now beingmarketed as "desktop replacements," which are portable

systems powerful enough to serve as a primary system Thischapter examines the phenomenon of portable computing,

showing how it has evolved and why it is so popular

Portables started out as suitcase-sized systems that differedfrom desktops mainly in that all the components, including aCRT-style monitor, were installed into a single case In the early1980s, a small Houston-based startup company named Compaqwas among the first to market portable PCs such as these

Although their size, weight, and appearance are almost

laughable when compared to today's laptop or notebook

systems, they were cutting-edge technology for the time Infact, unlike modern laptops, the components used by these

bulky first generation portables were virtually identical to thoseused in the most powerful desktops of the day

Most current portable systems are now approximately the size

of the paper-based notebook they are often named for and arebuilt using the clamshell design that has become an industrystandard Inside these systems, nearly every component hasbeen developed specifically for use in mobile systems

Portable PCs, however, are not the same as Personal DigitalAssistants (PDAs), such as the Palm series, Handspring, andPocketPC Portable computers differ from PDAs in that they usethe same operating systems and application software as

desktop computers and use memory, CPU, and drive

technologies that are similar to desktop PCs as well PDAs, on

focuses primarily on laptops or notebook-style portable PCs.That said, in terms of technology, much of this book will also beapplicable to a relatively new category of portables: Tablet PCs.Actually Tablet PCs have been around since the early '90s, but alack of standardized software, combined with relatively low

power and functionality, limited them to special applicationsrather than mainstream use In many respects, modern TabletPCs are identical to laptop/notebook computers except that

they are equipped with a touch-sensitive display, lack the

integrated removable storage (such as a CD/DVD-ROM drive),and include a special tablet-oriented version of Windows Whilemost include a keyboard and basically look like a standard

notebook computer, a few Tablet PCs do not come with a

keyboard at all Those that don't include a keyboard generallyoffer one as an accessory or can use any standard external

keyboard if desired

Many people use portable systems as an adjunct or accessory

to a primary desktop system in their principal working location

In those cases, the portable system may not need to have allthe power of a desktop, since it will only be used when awayfrom the main office In my situation, the roles are reversed All

my professional life I have been teaching PC hardware and

software, usually on the road As such I have always needed apowerful computer I can take with me, and because the amount

of time spent traveling is equal to or more than the amount oftime spent at a home office, I have had to rely on portable PCs

of one type or another as my primary system

All my books on upgrading and repairing PCs, starting with myfirst self-published seminar workbooks in 1985, have been

written on a portable system of one type or another With theprocessing power of modern laptop/notebook systems evolving

smaller, lighter, and more powerful laptops in the future

Portable computers have settled into a number of distinct rolesthat now determine the size and capabilities of the systemsavailable Traveling users have specific requirements of portablecomputers, and the added weight and expense incurred by

additional features make it less likely for a user to carry a

system more powerful than is necessary Others may not domuch traveling, but simply like the flexibility and small footprintthat a laptop provides

Portable System Design Elements

Obviously, portable systems are designed to be smaller andlighter than desktops, and much of the development work thathas been done on desktop components has certainly

contributed to this end Much of this development has been insimple miniaturization For example, whereas 3.5-inch harddrives may be popular on desktops, most laptops would nothave room for these devices Instead, they normally use 2.5-inch hard drives, which are a direct result of the miniaturizationthat has occurred in hard-drive technology over the past fewyears Some of the subnotebook and Tablet PC systems useeven smaller 1.8-inch drives first made popular in portable

music players

In addition to miniaturization, however, advancements in threeother areas have contributed greatly to the design of today'slaptop computers: flat-panel displays, power systems, and

thermal management

Flat-Panel Displays

The sleek lines of flat-panel Liquid Crystal displays (LCDs) have

exclusively in the domain of laptops

A flat-panel display is one of the most visually apparent

components of a laptop They are also usually the componentthat has the greatest impact on the size, shape, and cost of alaptop In the early days of portables, the only affordable

portable display was the small CRT monitor, a device that was

so power-hungry that it required AC power These displays werealso bulky, causing early portables to look like small suitcases.When gas-plasma displays became available, the size of

portables diminished to that of a lunchbox or briefcase Still, thepower requirements of gas-plasma displays again mandated anearby AC outlet It was not until the development of large,low-power LCDs that the familiar clamshell-style, battery-

powered laptop became a reality

As the internal components of a laptop became increasinglysmall, the laptops gradually shrunk in size to the point wherethey were no larger than a paper notebook Indeed, the

category of notebook computers originally started out with afootprint no larger than 8.5x11 inches In the past few years,however, as high-quality LCD screens became available in largerand larger sizes, the size of some notebooks also increased

Low Power Consumption

Like the car that spends most of its time in a garage, or thepleasure boat that spends most of its time at the dock, portablecomputers spend most of their time in a decidedly non-mobileenvironmenton a desk connected to an AC power outlet Takeaway a laptop's battery, however, and you have greatly

diminished its value In fact, one of the primary features of

importance to a laptop buyer is the "battery life"the length of

operating a computer from a battery imposes system limitationsthat designers of desktop systems never had to consider beforethe advent of battery-powered portable systems What's more,the demand for additional features, such as DVD and CD-RWdrives, larger displays, and ever faster processors, has

enormously increased the power drain on the typical system.The problem of conserving power and increasing the system'sbattery life is typically addressed in three ways:

Low-power components Nearly all the components in

today's portable systems, from CPUs to memory to displaysand drives, are specifically designed to use less power thantheir desktop counterparts

Increased battery efficiency Newer battery technologies,

such as lithium ion and lithium polymer, are enabling

batteries and power supplies to be lighter and have greatercapacities, allowing for longer battery life on a single

charge

turn off specific system components, such as disk drives,when they are not in use can greatly increase battery life

Thermal Management

Perhaps a more serious problem than battery life in portablesystems is heat All electrical components generate heat, of

course, and in the confines of a laptop this heat can be a

significant problem Inside a laptop, a large number of

components are packed in a relatively small space, creating anextremely high concentration of thermal energy This energymust somehow be dissipated In most desktop systems, this is

empty spaces inside the system Because fans use up batterypower, however, portable systems must be designed to run fan-free most of the time and therefore employ innovative systemsfor moving and dissipating heat

The worst culprit, as far as heat is concerned, is the systemprocessor When they were first released, the amount of heatgenerated by Intel's 486 and Pentium processors became a

problem even in desktop systems Newer and faster processorsconsume more and more power It became clear to processormanufacturers such as Intel and AMD that special processordesigns would be necessary to reduce power consumption andthermal output in mobile systems Modern mobile processorsbenefit from technology featuring lower voltages, smaller diesizes, larger integrated caches, and, in general, lower powerconsumption than their predecessors

Because many portable systems are now being designed asreplacements for desktops, they require the most powerful

processors available Even the newest and fastest processorsdesigned for desktop systems are often adapted for use in

mobile systems Even with dedicated designs for mobile

systems, these high-speed processors can generate surprisinglylarge quantities of heat

To address this problem, Intel and AMD have created specialmethods for packaging mobile processors that are designed tokeep heat output to a minimum Mobile processors also reduceheat through the use of extra-low-voltage designs (multiplevoltages in recent designs) and by integrating both the Level 1and Level 2 memory cache directly on the processor die Thesetechniques, by the way, not only reduce heat but also lowerpower demands and thus increase battery endurance

However, even the best mobile processor designs will still result

in a substantial quantity of heat being generated in a small

components are designed not only to require little space andpower but also to be able to withstand high temperatures

The Popularity of Portables

Office staffers frequently have to take work home Salespeopleregularly crisscross the country, spending more time in theircars than at their desks Construction engineers need

computing power, but rarely sit inside a traditional office It is

no wonder that portable computers have had an almost

continuous presence in the computer industry In fact, not only

do portable computers comprise a significant portion of totalannual computer sales, that portion is continually growing, and

is even exceeding that of desktop systems in some cases Forexample, according to the research firm Current Analysis,

laptops outsold desktop systems for the first time in the U.S.during the calendar month of May, 2005, accounting for 53percent of the total market during that month, up from 46

percent during the same period in the previous year

As further evidence of the popularity of laptops, Intel said thatabout 31 percent of its processors will end up in mobile

computers in 2005, compared with only 17 percent in 1999.IBM reported in 2000 that they sold a total of 10 million

ThinkPad laptops in the 8 years since their first appearance onthe market in 1992 They doubled that figure to 20 million totalThinkPad laptops by 2003, only 3 years later Not only are

laptops growing in popularity as compared to desktops, but thetotal market for laptops has been increasing as well According

to DisplaySearch Inc., laptop sales for 2004 were expected toexceed 46 million units, an astonishing figure when you look atit

Finally, according to Charles Smulders, vice president and chiefanalyst at Gartner Dataquest, "…the mobile segment has

by over 50 percent For every four PCs shipped, one is now amobile, and this share is projected to rise further, approachingone in three by 2006."

Who's Selling Laptops?

Because of their popularity, laptop and notebook computers areavailable from a large number of vendors Table 1.1 lists themajor laptop/notebook vendors in the U.S., along with the

mainland China as well The largest builder of notebooks in thatcountry is Lenovo, who acquired IBM's Personal Computing

Division (global desktop and notebook PC business) in 2005.This acquisition makes Lenovo/IBM the third-largest global PCleader, behind Dell and HP/Compaq

Except for a short time at the very beginning, the personal computer revolution has always been accompanied by an equally innovative portable computer revolution Indeed, in many ways, the evolution of portables has been much more dramatic than that of desktops.

Whereas standard desktop computers have not changed markedly in their overall size in more than 20 years, portables have shrunk from the size of a suitcase to the point where one can fit one into a shirt pocket.

Pre-PC Portables

Some people date the beginning of the personal computer revolution as August 1981, when the original IBM PC was introduced This landmark system was preceded, however, by a number of important computers, some of which were portable.

Luggables

Most early portable systems started out as nothing more than desktop PCs with integrated CRT displays, keyboards, and of course a handle These systems weighed between 25 and 50 pounds and were the size

of sewing machines or small suitcases At first, this category was simply

labeled as portable But years later, when significantly smaller laptops appeared, these systems were branded as transportables or luggables.

It might be hard for current laptop users to believe this, but it was quite common in the 1980s to see businessmen lugging these 30 to 50- pound behemoths from one appointment to another For obvious

reasons, however, these giant computers were soon supplanted by a new generation of portables that were significantly easier to carry.

IBM 5100

In September 1975just months after the original personal computer was introduced under the Altair nameIBM introduced its 5100 Portable Computer (see Figure 1.1 ) Although it was hardly something anyone would happily carry, weighing in at 50 pounds, the 5100 holds the distinction of being the first portable computer in history, and very nearly the first personal computer, period.

Figure 1.1 The IBM 5100 (Photo from www.ibm.com.)