Defining the Portable Computer
| Portables, like their desktop counterparts, have evolved a great deal since the days when the word portable could refer to a desktop- sized case with a handle on it. Today, portable systems can rival the performance of their desktop counterparts in nearly every way. Many systems are now being marketed as "desktop replacements ," which companies are providing to traveling employees as their primary systems. This chapter 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 differed from desktops mainly in that all the components, including a CRT-style monitor, were installed into a single case. In the early 1980s, a small Houston-based startup company named Compaq was among the first to market portable computers such as these. Although their size, weight, and appearance are almost laughable when compared to today's portables, they were cutting-edge technology for the time. In fact, unlike the case today, the components used by these bulky portables were almost identical to those used 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 are built using the clamshell design that has become an industry standard. Inside these systems, nearly every component has been developed specifically for use in mobile systems. Portables, however, are not the same as Personal Digital Assistants (PDAs), such as the Palm series, Handspring, and PocketPC. Portable computers differ from PDAs in that they use the same operating systems and application software as desktop computers and use memory, CPU, and drive technologies that are similar to desktop PCs. PDAs, on the other hand, use different operating systems, applications, and hardware compared to either desktop or portable PCs and thus fall outside the scope of this book. Instead, this book focuses on laptops or notebook-style portable computers. That said, in terms of technology, much of this book will also be applicable to a relatively new category of portables: Tablet PCs. In many respects these computers are identical to 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. All my professional life I have been on the road teaching PC hardware and software. Because I am almost never home or at a single desk, I have had to rely on portable systems ”usually as my primary system, if not my only one. All my books on upgrading and repairing PCs, starting with my first self-published manuscripts in 1985, have been written on a portable system of one type or another. With the processing power of modern notebook systems now all but equaling that of desktop systems, I look forward to carrying even smaller, lighter, and more powerful systems in the future. Portable computers have settled into a number of distinct roles that now determine the size and capabilities of the systems available. Traveling users have specific requirements of portable computers, 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. Portable System Design ElementsObviously, portable systems are designed to be smaller and lighter than desktops, and much of the development work that has been done on desktop components has certainly contributed to this end. Much of this development has been in simple miniaturization. For example, whereas 3.5-inch hard drives may be popular on desktops, most notebooks would not have room for these devices. Instead, they use 2.5-inch hard drives , which are a direct result of the miniaturization that has occurred in hard-drive technology over the past few years . In addition to miniaturization, however, three other elements have contributed greatly to the design of today's notebook computers: flat-panel displays, power systems, and heat management. Flat-Panel DisplaysThe sleek lines of flat-panel LCD displays have caused them to be seen increasingly more often on desktops. It was not long ago, however, that these displays were exclusively in the domain of laptops. Flat-panel displays are the most visually apparent component of a laptop. They are also usually the component that has the greatest impact on the size and shape of a laptop. 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 were also bulky, requiring early portables to look like suitcases. When gas-plasma displays became available, the size of portables diminished to that of a lunchbox. Still, the power requirements of gas-plasma displays again mandated a nearby AC outlet. It was not until the development of large, low-power LCD displays that the familiar clamshell-style, battery- powered laptop became a reality. As the internal components of a laptop became increasingly small, the laptops gradually shrunk in size to the point where they were no larger than a paper notebook. Indeed, the category of notebook computers originally started out with a footprint no larger than 8.5x11 inches. In the past few years, however, as high-quality LCD screens became available in larger and larger sizes, the size of some notebooks also increased in size. PowerLike the car that spends most of its time in a garage, or the pleasure boat that spends most of its time at the dock, portable computers spend most of their time in a decidedly nonmobile environment ”on a desk connected to an AC power outlet. Take away a laptop's battery, however, and you have greatly diminished its value. In fact, one of the primary laptop features of importance to a buyer is the "battery life" ”the length of time the system can run on a single battery charge. Environmental concerns are leading to the development of more efficient power-management technologies, but, obviously, operating a computer from a battery imposes system limitations that designers of desktop systems never had to consider before the advent of battery-powered portable systems. What's more, the demand for additional features, such as DVD and CD-RW drives, 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's battery life is typically addressed in three ways:
Heat ManagementPerhaps a more serious problem than battery life in portable systems is heat. All electrical components generate heat, of course, and in 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 a concentration of thermal energy. This heat must somehow be dissipated. In desktop systems, this is accomplished by using fans that continuously ventilate the empty spaces inside the system. Because fans use up battery power, however, portable systems must be designed to run fan-free most of the time and therefore employ innovative systems for moving and dissipating heat. The worst culprit, as far as heat is concerned , is the system processor. When they were first released, the amount of heat generated by Intel's 486 and Pentium processors was a problem even in desktop systems. Heatsinks and tiny fans mounted on top of the CPU became standard components in most systems. Modern systems based on Pentium III, Celeron, Pentium 4, and AMD's Mobile Athlon processors benefit from newer processor technology featuring lower voltages, smaller die sizes, integrated L2 cache, and in general lower power consumption than their predecessors. Because many portable systems are now being designed as replacements for desktops, they require the most powerful processors available. Even the newest and fastest processors designed for desktop systems, such as the AMD Athlon and Intel Pentium 4, are quickly adapted for use in mobile systems. These high-speed processors generate surprisingly large quantities of heat. To address this problem, Intel and AMD have created special methods for packaging mobile processors that are designed to keep heat output to a minimum. Mobile processors also reduce heat through the use of extra- low-voltage designs (dual voltage in some cases) and by integrating the Level 2 memory cache directly on the processor die. These techniques, by the way, not only reduce heat but also lower power demands and thus increase battery endurance . Even the best laptop thermal-management design will still result in a substantial quantity of heat being generated in a small space. Usually this heat is more concentrated than that inside a desktop. To cope with this problem, many notebook components are designed not only to require little space and power but also to be able to withstand high temperatures . The Popularity of PortablesOffice staffers frequently have to take work home. Salespeople regularly crisscross the country, spending more time in their cars than at their desks. Construction engineers need computing power but rarely sit inside a traditional office. It is no wonder that portable computers have been an almost continual presence in the computer world. Once the value of personal computers is proven to a given worker, the next desire is to take that value somewhere else. In fact, not only do portable computers comprise a significant portion of total annual computer sales, that portion is continually growing. According to Charles Smulders, Vice President and Chief Analyst at Gartner Dataquest, " the mobile segment has represented one of the few areas of sustained growth in an otherwise difficult PC market. Between 1998 and mid-2002, mobile PCs increased their unit share of the global PC market by over 50 percent. For every four PCs shipped, one is now a mobile, and this share is projected to rise further, approaching one in three by 2006." Who's Selling Laptops?Because of their popularity, notebook and laptop computers are available from a large number of vendors. Table 1.1 lists the major notebook vendors in the U.S., along with the brand names associated with those vendors . Table 1.1. Major Laptop Vendors in the United States
Although there are many vendors of notebooks, most vendors do not themselves manufacture these devices. In fact, 65% of all notebooks in the world are produced in Taiwan by one of several companies located there. These companies are not well known because the notebooks they manufacture are usually labeled not with their own name but with that of a notebook vendor. Here's a list of the major manufacturers in Taiwan; a few of these companies also sell notebooks under their own labels:
An increasing portion of notebooks is being produced in China. The largest builder of notebooks in that country is Legend.  |
EAN: 2147483647
Pages: 182