Laptop Introduction

A laptop or simply notebook is a small mobile computer, typically weighing 3-12 pounds (around 1.3 to 5.4 kilograms), although older laptops may weigh more. Laptops began from a desire to have a full-featured computer that could be easily used anywhere. Their predecessor was called the luggable.

Laptops usually run on a single main battery or from an external AC/DC adapter that charges the battery while also supplying power to the computer itself. Many computers also have a 3 volt cell to run the clock and other processes in the event of a power failure.

Laptops contain components that are similar to their desktop counterparts and perform the same functions, but are miniaturized and optimized for mobile use and efficient power consumption. Laptops usually have liquid crystal displays and most of them use different memory modules for their random access memory (RAM), for instance, SO-DIMM in lieu of the larger DIMMs. In addition to a built-in keyboard, they may utilize a touchpad (also known as a trackpad) or a pointing stick for input, though an external keyboard or mouse can usually be attached.

TYPES:

MAINFRAME: Laptops weighing between 5 and 7 lb (2.3–3.2 kg) with a screen size of 14.1 or 15.4 inches (35 or 39 cm) diagonally.

DESKTOP REPLACEMENT: A desktop replacement computer is a personal computer that provides the full capabilities of a desktop computer while remaining portable. Because of their increased size, this class of computer usually includes more powerful components and a larger display than generally used in smaller portable computers and can have a relatively limited battery capacity. Some use a limited range of desktop components to provide better performance per dollar at the expense of battery life. Powerful laptops meant mainly used for fun and infrequently carried out due to their weight and size; the latter provides more space for powerful components and a big screen, usually measuring 17–20 inches (43–51 cm). Desktop replacements tend to have limited battery life, rarely exceeding three hours, because the hardware is not optimized for efficient power usage. An example of a desktop replacement computers are gaming notebooks, which are designed to handle 3D graphic-intensive processing for gamers.

SUBNOTEBOOK: Laptops weighing typically between 4.6 and 6 lb (1.8–2.7 kg) and a screen of 10.6 to 13.3 inches diagonally. A subnotebook is a small and lightweight portable computer, with most of the features of a standard laptop computer but smaller. The term is often applied to systems that run full versions of desktop operating systems such as Windows or Linux, rather than specialized software such as Windows CE, Palm OS or Internet Tablet OS.

PARTS:Feature 12 inch (30 cm) or larger active matrix displays with resolutions of 1024?68 pixels and above, and have a PC Card (formerly PCMCIA) or Express Card expansion bay for expansion cards. Internal hard disks are physically smaller—2.5 inch (60 mm). Higher end laptops can come with dedicated graphics processors, such as the Dell Inspiron E1505 and E1705, which can be bought with an ATI Mobility Radeon X1300 or similar or the MacBook Pro which comes standard with an nVidia 8600M GT. These mobile graphics processors tend to have less performance than their desktop counterparts, but this is because they have been optimized for lower power usage. Laptop specific processors come in a wide range from Intel (Pentium M, Celeron, Intel Core and Intel Core 2), AMD (Athlon, Turion 64, and Sempron) and from VIA (C3 and C7-M). Motorola and IBM developed and manufactured the chips for the former PowerPC-based Apple laptops (iBook and PowerBook). Generally, laptop processors are less powerful than their desktop counterparts, due to the need to save energy and reduce heat dissipation. Current models of laptops utilize lithium ion batteries with more recent models using the new lithium polymer technology. These technologies have largely replaced the older nickel metal-hydride batteries. Typical battery life for most laptops is two to five hours with light-duty use, but may drop to as little as one hour with intensive use. Batteries gradually deteriorate over time and eventually need to be replaced in one to five years, depending on the charging and discharging pattern.

DISADVANTAGES: Parts standardization and compatibility issues. While there are accepted world standards of form factors for all the peripherals and add-in PC cards used in the desktop computers, there are still no firm worldwide standards relating to today's laptops' internal form factors, such as supply of electric voltage, motherboard layouts, internal adapters used in connecting the optical drive, LCD cable, keyboard and floppy drive to the main board. Most affected by this are users uneducated in the relevant fields, especially if they attempt to connect their laptops with incompatible hardware or power adapters. Some parts, such as hard drives and memory are commodity items and are interchangeable. However, other parts such as motherboards, keyboards, and batteries are proprietary in design and are only interchangeable within a manufactures brand and/or model line. Due to their portability and tight integration, laptops are more subject to wear and physical damage than desktops. Components such as batteries, screen hinges, power jacks, and power cords are commonly subject to deterioration due to ordinary use.

Upgradeability: Laptops' upgradeability is severely limited, both for technical and economic reasons. Each major laptop vendor pursues its own proprietary design and construction, with the result that laptops are difficult to upgrade and exhibit high repair costs. With few exceptions, laptop components can rarely be swapped between laptops of competing manufacturers, or even between laptops from the different product-lines of the same manufacturer. Many laptops have removable CPUs, although support for other CPUs is restricted to the specific models supported by the laptop motherboard. The socketed CPUs are perhaps for the manufacturer's convenience, rather than the end-user, as few manufacturers try new CPUs in last year's laptop model with an eye toward selling upgrades rather than new laptops. In many other laptops, the CPU is soldered and non-replaceable.

PERFORMANCE: For a given price range (and manufacturing base), laptop computational power has traditionally trailed that of desktops. This is partly due to most laptops sharing RAM between the program memory and the graphics adapter. Desktop computers and their modular components are built to fit much bigger standard enclosures, along with the expectation of AC line power. As such, energy efficiency and portability for desktops are secondary design goals compared to absolute performance. With the advent of dual-core processors and perpendicular recording, laptops are beginning to close the performance gap with desktops. Intel's Core 2 line of processors is efficient enough to be used in portable computers, and many manufacturers such as Apple, Lenovo and Dell are building Core 2 based laptops.

More Laptop Articles & Laptop Reviews

	Belkin 17 Inch Messenger Bag Review If you are one of the type of people that need a little help in order to stay organized, well then this is the messenger bag for you! Built-for-You organization inside gives you tons of places for your MP3 player, business cards, pens, and other things – really anything that you...More
	Targus CVR600 15 Inch Groove Notebook Backpack Review There is something to be said about a company that makes notebook backpacks – they are freaking cool! Although this was designed for the college student market, notebook backpacks are being picked up by corpo...More
	Targus TCM004US Messenger 15 Inch Notebook Case Review This is the greatest notebook case and the single most affordable notebook case – hands down! Although I had some reservations about buying a notebook case online, and even went as far as going to several sto...More