The Power of Your Computer










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The first step to having a good relationship with your personal computer, or PC, is to get to know it a little better. Having a basic understanding of what the different bits and pieces of hardware that make up your PC are can really help. From the motherboard, that is the backbone of your PC, to the speakers that pump out all the sounds, this section will tell you what each does and how they all work together to make your PC tick. Even if you do not need this sort of information on a daily basis, it can prove very helpful in a number of different kinds of scenarios. A good, general understanding of what is what, and how it does what it does can really be helpful: When you are investigating your PC's ability to perform any given task; when you are trying to decide what might be done to improve your PC's current performance; and last, but certainly not least, when you are out in the marketplace trying to decide what you need (and what you don't need) included in your new PC!


The computer is a very powerful machine that can perform millions of calculations per second through the use of electronic circuits. Surprisingly, the computer can do all of its functions simply by detecting if electricity is on or off in a given circuit position.

Remember that the three primary functions of a computer system are input, process, and output. Before information can be processed and output, the data must be entered into the system. This data, before it is processed, is referred to as the input data. Once the data has been input (through the input devices), and processed (using the processor and software programs), it is normally output or stored. Output is the result of calculating, rearranging, reformatting, or otherwise manipulating, raw input data.

As a way of thinking about this input-process-output cycle, let's assume you wanted to average three test scores. You must first enter the scores. This would give the computer system some raw data or input to work with. The processing step would be to add the three scores together and divide the sum of the scores by three. Finally, the output step would be to display the average. As you can see, without the input, there would be no data to process, and no average to display. Since the input data is the beginning point for the processing, the output can be no more accurate than the input. This example of bad input data gives us the term: Garbage In, Garbage Out. In other words, if you input garbage (or incorrect data) into the computer system, you should expect garbage (or incorrect information) as output from your computer system. In fact, the predominant source of errors in a computer system is incorrect input.


Computer hardware consists of the devices and equipment that make up the computer system. Stated simply, if you can touch it, it is computer hardware. Personal computers are usually made up of several different components, such as the system unit, keyboard, and monitor.

Typically, the system unit, the heart of your computer, is a cabinet, tower or case that houses many electronic components and serves as the main connecting point for other devices. This case houses all of the vital working parts of your PC, keeping them shielded from the "dangers" of the outside world (such as, dust, dirt, kittens, static electricity, etc.). System units are available in several different styles, including desktop, vertical and laptop models. While the cases are different, each system unit contains many of the same components that enable the computer to process information.

The system unit in the desktop model computer furnishes the base for the monitor. In the vertical configuration, the system unit stands on its side and is often placed on the floor next to a desk. The main advantage of the vertical configuration is that less desk space is used by the computer. Both the desktop and the vertical system unit designs typically allow you to add many features to the computer by just plugging in the new device. The laptop computer combines all the components of a computer into one small case, saving space and weight. Because of their small size, however, laptops are usually more difficult to expand than are desktop and vertical models.

How a PC Works

Essentials --

A good place to begin is to get a grasp of the relationship between the central processing unit (or CPU), the hard drive (HDD or Hard Disk Drive), and the system memory (RAM). Despite the best intentions of those in the know to explain the differences between the hard drive and system memory, a lot of folks still confuse the two. As both of these components are used to "remember" things, that is very understandable.

One way to look at the relationship between the hard drive and system memory is to think of your PC as an automobile service station. So…your PC is a service station that you are taking your car to for servicing. This being the case, then the CPU is the mechanic who performs all the work, the RAM is the service bay where all the work is performed, and the hard drive is the store room where all the parts that may be needed are kept for quick access by the mechanic.

With this analogy in mind, a quick read through the rest of this section should clear up any lingering questions you may have about how your PC functions as a whole and what each component is responsible for.

Central Processing Unit (or CPU):
At the heart of a PC beats a mighty silicon beast. This is the CPU, or processor, and its job is to do all the calculating necessary to turn the binary digits that data is stored in into useable information, like the programs and files you see onscreen. This is the main component of the computer and is responsible for everything that your PC does. The CPU is often referred to as a "computer on a chip" because it is contained on a small electronic circuit chip that is called a microprocessor. The microprocessor contains many thousands of miniature electronic components on a piece of silicon smaller than a postage stamp.

Microprocessors are rated by the speed at which they can make calculations, also called clock speed. Every computer contains an internal clock that regulates the rate at which instructions are executed and synchronizes all the various computer components. The CPU requires a fixed number of clock ticks (or clock cycles) to execute each instruction. The clock speed determines how many instructions per second the processor can execute, so the faster the clock, the more instructions the CPU can execute per second. This speed is always stated in Hz (one Hz, or Hertz, is one calculation). We're used to see the speed stated in MHz (MegaHertz or one million Hz), but as PCs got faster and faster very quickly, you will now also see speeds stated in GHz (GigaHertz or one billion Hz).

A common speed these days is a 2.0GHz processor. This means that the processor can make 20,000,000,000 calculations per second--2000 x 1,000,000 (Mega) x 1 (Hz) calculations per second. That's a whole lot of calculating going on! The thing to keep in mind here is that a 2.0GHz processor is faster than 1.8GHz processor and so on.

You can still buy PC's that run at under even 1.0Ghz, and they are only a couple of hundred dollars.  The usual marketing propagandas ensure people only want the latest, sexiest, and more importantly FASTEST machines out there today.
Currently the higher end stands at around 3.2Ghz, but that is an ongoing bar raising feature of computers.
(At the start of 2003 this section spoke of machines around 1Ghz being the norm, and six month before that, it was a mere 500Mhz, so you see how fast things evolve)

The internal architecture of a CPU has as much to do with a CPU's performance as the clock speed, so two CPUs with the same clock speed will not necessarily perform equally. For example, processors have some memory built into them, giving them the ability to retain a small amount of data. This built-in memory, or cache, saves the processor from having to go back to the system memory or the hard drive every time that data is needed. The amount of cache memory that your processor has depends on the processor you have. Some have two separate cache memories (L1 and L2), while others only have one or the other of the two. This cache memory can also be different sizes. So, generally, the more cache memory your processor has built into it, the faster it will perform.

Motherboard: Because the CPU handles all operations in the computer, it must be connected to every device installed in the system. To facilitate this, computer manufacturers plug the CPU chip into a special socket on the main electronic circuit board located in the system unit cabinet, called the motherboard. The motherboard, also referred to as the mainboard, is the communications center through which all the components that make up your PC transmit information back and forth. Every component--from the central processing unit (CPU) that processes data to the joystick used to play games--is plugged into the motherboard in one way or another.

There are lots of components built into motherboards. From the BIOS that controls the basic communication functions between components, to the battery that keeps the clock ticking when your PC is turned off, each of these components is responsible for a different task and is critical to the operation of your PC. There are about a zillion tiny resistors, capacitors and solder leads all over the motherboard. Most of these bits will never concern you in any major way. Suffice it to say that they are all there for a very specific reason.

The other major function of the motherboard is to supply all of the components plugged into it with power. It will control and dole out the proper amount of electrical current required by each individual component. The motherboard also provides connections for the computer keyboard, disk drives, monitor and other devices. In addition, the motherboard also provides special sockets where additional memory or primary storage can be added.

If you were to take the cover off the system unit, you would notice that there are several special receptacles located on the motherboard. These sockets are called expansion slots, and allow you to plug in special electronic circuit boards that perform additional processing functions. These plug-in boards are called expansion cards, and can provide you with extra RAM, FAX capabilities, telephone connections and much more. By using expansion cards and slots to add features to the computer, it is easier to make the computer do exactly what you need it to do. This ability to enhance your personal computer by simply plugging in an expansion card contributes greatly to the computer's flexibility and popularity.

How Motherboards Work

Data Storage --

The computer can process considerable amounts of information quickly and accurately, but before processing can occur, the computer must be able to access the information.

All of the data contained in your PC is stored on your Hard Drive (HDD or Hard Disk Drive). Programs, documents, pictures, home videos, etc. are all forms of data that must be stored somewhere and able to be accessed when you need the data. Represented on your computer as the C: drive, your hard drive supplies this storage space on a series of magnetic disks that can be both read from and written to at any time. Disks store information magnetically and must be rotated mechanically like a long-play record before the information on them can be accessed. This means that these storage devices are much slower to operate than RAM. However, unlike RAM, they can store vast amounts of information very inexpensively.

The hard drive is the only drive that is not visible from the exterior of your PC. It is safely tucked away inside the case since there is no need to be able to access the hard drive, as all of its disks are fixed and cannot be removed (as CD-ROM or floppy disks can). Hard drives come in different sizes (or capacities). The more data you wish to keep on your hard drive, the larger its storage capacity will need to be.

System memory, Random Access Memory (or RAM), is used to temporarily hold information, programs or other data that your PC needs to access quickly. Instead of having to read information from the hard drive all the time, your PC will find all the data that it needs to run a program and load it all into the RAM, where it can be accessed very quickly.

As you work with your PC, you may be creating new data that needs to be stored somewhere. This new data is stored temporarily in the RAM until you use the program's "save" function to write it to the hard drive. For example, when you are composing a letter on your PC, each character that you type is being saved in the RAM, allowing you to make changes to your letter very quickly. If it were being written to the hard drive as you typed, and you wanted to correct the spelling of a word, your PC would have to search the hard drive for the word and then re-write it with the new spelling.

The amount of RAM that your PC is equipped with will dictate not only how much data can be worked with at any given time, but also how quickly work can be done. Some of your RAM will be used by your operating system (such as Windows); some more will be used by the programs you are running; and still more will be used by any new data that you may be creating. If, for example, your system only has 32 MB of RAM and your operating system is using 15 MB, while the programs you are running are using 15 MB, if you then create 2 MB of data, there won't be any room left for more data. This situation will make your PC slow down considerably as your operating system will begin to swap data to and from a section of your hard drive that Windows keeps set aside as a swap file. The data in this swap file cannot be accessed anywhere near as quickly as data that is stored in RAM; hence, the system slows down.

There are several different types of RAM that your system may be equipped with. Regardless of the exact type of RAM you have, the functions it performs and the way these functions are performed remain basically the same.

It's important to remember that data stored in RAM will be lost when the computer's power is turned off. Data that is stored in RAM is actually neatly arranged electrical signals, which need a constant supply of power in order to remain intact. When your PC is turned off, there is no longer power flowing through the RAM, and all the data that was temporarily stored there is lost. This is why it is important to save information to the hard drive before shutting down your computer. Also, if you are working on your computer and there is a power failure, everything you have done since you last saved it to your hard drive will be lost. For this reason, it is a good practice to save work frequently.

Graphics cards (also known as video cards, or display adapters) can be a crucial part of your entire system set up, as this will effect how you see things on your monitor.  The original arguments of "doing homework" or "research" on a home computer are usually from the people in your house that will indeed need to be concerned with this area.

Your PC will not function without one, as a graphics card is part of the computers waking up (boot) process, but like everything, there are a multitude of options that allow for endless debate as to which one to choose. The graphics card is where you attach the monitor.  The monitor itself could be the most up-to-date thing out of some companies' R&D labs, but without a graphics card capable of doing certain things, it may not do much more than show you the operating system, and a few of the programs it has to offer.  For business work, there really isn't any need to concern yourself with any particular features of a specific card, as even cards that are built into the motherboard, will be more than sufficient.  For anything slightly more exciting you are going to have to look a little deeper.

How Graphics Cards Work
Learn More: Shop for Graphics Cards

There are lots of different types of graphics cards around, and the selection is made more confusing by the fact that lots of people make the cards that you put inside your PC.  However, there are relatively few manufacturers making the CHIPS that sit ON those cards. So if you see or hear about a particularly great graphics card that you simply MUST have, be sure that you check out the manufacturer of the card, not just concentrate on the name of the chip that you are seeing--similar to the way that anyone can build a PC from component parts and call the final assembled beast what ever they want.  Because you have a Porsche steering wheel does not make your car a Porsche (although a Porsche does indeed have a Porsche steering wheel).

Sound cards are another area to watch for, although they tend to be slightly less prolific than graphics cards. Not the same attention seems to be heaped upon them, probably as they are less apparent in the WOW stakes, when it comes to advertising. Many motherboards come with integrated soundcards (as they do graphics cards) and a LOT of people seem happy with those.  For those using a PC specifically focusing on audio, this is obviously something you would want to know as much about as possible. For the rest of us, there are also some benefits to not entirely ignoring the sound card issue.

How to Choose a Sound Card

With the integration of DVD drives as standard in many off-the-shelf computers, the mention of surround sound comes into the picture (if you can excuse the pun). There are a lot of sound cards that will support a full 5.1 surround sound experience. Games, too, now take advantage of surround sound. So you can hear the shot from behind you, thud of the bullet right in the center, the splash of blood some way out in front, and then the mocking tones of your adversaries way off somewhere in the distance.

The CD-ROM (Compact Disk-Read Only Memory) Drive is the most common type of removable media device after the floppy disk drive. For many years, the CD-ROM has been used to permanently store large amounts of data. Most, if not all, the software that you will install on your PC is supplied to you on CD-ROM. The disks hold a large amount of data in a very small space. Where a floppy disk will only hold 1.44 MB of data, a single CD-ROM will typically hold about 650 MB.

Another great feature of the CD-ROM drive is that it is perfectly capable of playing your favorite music CDs as well, provided that the drive is hooked up to your sound card or plugged into your motherboard (if you should happen to have onboard sound).

The only thing that has really changed with CD-ROM drives over the years is that the speed at which they can read and transfer data from the disks has increased dramatically. This speed increase is what is indicated by the "times" number that is associated with the drive. For example, a 50x CD-ROM drive that you might buy today will read at a maximum rate 50 times faster than the very first, 1x CD-ROM drives. The original speed rating of 1x meant that the drive could read a maximum of 150 Kilobytes of data from the disk every second. Knowing this, we can figure out that a 50x drive will read from the disk at a maximum rate of 7500 Kilobytes (or 7.5 Megabytes) per second. What all this added speed means is that you will spend much less time waiting for data to be transferred from the CD-ROM to your hard drive when you are installing a program or copying data from a CD.

A CD-RW (Compact Disk-Read/Write) Drive, also commonly known as a CD-Writer or CD Burner, can be used instead of, or in addition to, a CD-ROM drive. The major difference between a CD-RW drive and a CD-ROM drive is that with a CD-RW drive you can write to CDs, as well as read information from them. This requires special types of CDs: CD-Rs (can be written to once and then only read from thereafter) and CD-RWs (can be written to again and again). These drives have read speeds very similar to those of today's CD-ROM drives, but the process of writing to the special disks is still a fair bit slower.

This type of drive is very handy for doing things like creating your own custom music CDs, backing up large amounts of data for safety's sake, and for storing large files, like digital pictures and digital home videos that you do not need to access on a regular basis.

The Floppy Disk Drive (or FDD) has been a PC component for a long time. You can quickly identify the floppy drive on the front panel of your PC: it will have a small slot into which the floppy disk can be inserted, and a little plastic button that is used to eject the disk. It is usually represented on your computer as the A: drive.

Nowadays, because of a floppy disk's relatively small storage capacity, it is no longer the removable media of choice in most instances. It will only hold 1.44 MB of data, as opposed to a CD-RW's 650 MB or more. However, it is a very cost-effective storage device because the drives themselves are not expensive and neither are the disks, which can be read from, written to and reused several times. The good old floppy disk is the perfect solution for moving small bits of data from one PC to another or for backing up small files.

DVD (Digital Versatile Disk) Drives are a recent addition to the drives category. They are designed to play DVD movies, but they are also very capable of being used as the primary disk drive for CD-ROMs as well. The future of the DVD format is looking very bright for several reasons. First of all, the DVD is capable of holding much larger amounts of data than current CD-ROM disks. Where a CD-ROM disk will typically hold 650-750 MBs of data, a DVD is capable of holding much more--from 4.7 GB (for 2+ hours of video) to 17 GB (for 8+ hours of video). In addition, while the standard CD (Compact Disk) and the standard CD-ROM are currently available with data storage on only one side of the disk, DVDs are available with data storage on both sides.Not only that, some of them are able to hold more than one "layer" of data on a single side!

There are recordable formats as well. These disks are called DVD-RAMs, and hold from 2.58 GB - 5.16 GB of data. This format of recordable disk will be an excellent medium for such things as full system back-ups and storage of digital home videos and digital photographs.

Most computers are equipped with special Read Only Memory (or ROM). This memory cannot be written to like RAM and cannot be erased when the power is turned off. Therefore, it is usually used by computer manufacturer's to store special instructions for the computer's use.

Input and Output Devices

The term input/output (or I/O) is used to describe any program, operation or device that transfers data to or from a computer, and to or from a peripheral device. Every transfer is an output from one device and an input into another. Devices, such as keyboards and mice, are input-only devices; while devices, such as printers, are output-only. A touch screen and a writable CD-ROM are both an input and an output device.

An input device is any machine or component that feeds data into a computer, allowing you to enter raw data or information. The function of any input device is to convert data found in the outside world into an electronic form that can be understood by the computer. For example, when you touch a key on a computer keyboard, the key touched is translated into an electronic image, passed through the processor, and stored in memory. Virtually any device that can translate data into an electronic signal can be an input device.

In order to output information, you must have an output device. An output device is any machine or component that is capable of representing information from a computer. Typically, output devices must have device drivers. Drivers are software programs that tell the output devices how to operate, and are necessary for the processor and the output device to work together.

There are many different types of input and output devices with variations on each type of device. The course will only discuss the most common devices, but you should remember that other devices can be used to input and/or output data.

This section will take a look at some commonly used input and output devices, each grouped into three categories: Touch, Visual (or Optical) and Sound (or Audio).

Touch Input Devices: To enter data from these devices, you must touch the device. Common input devices are the computer keyboard, mouse and drawing pad.

Computer keyboards are similar to electric-typewriter keyboards, but contain additional keys. The keys on computer keyboards are often classified as alphanumeric keys (letters and numbers); punctuation keys (comma, period, semicolon, and so on); and special function keys (control keys, arrow keys, Caps Lock key, and so on). In addition to these keys, IBM keyboards contain the following keys: Page Up, Page Down, Home, End, Insert, Delete, Pause, Break, Scroll Lock, Print Screen, and Num(ber) Lock.

There are also keyboards available that include some extra, specialized keys and/or buttons that make getting around quickly on the Internet, accessing and controlling multimedia functions (like volume, mute, play, etc.), and using your e-mail programs that much easier. Some even include features for putting your PC to "sleep" when you are away from it to keep your electric bill down.

A keyboard, is a keyboard, is a keyboard, right? Well, that used to be true, but it's not now. Recently, keyboard manufacturers have been adding many custom features to their keyboards. For one, the shape of keyboards has been changed in some models in order to reduce the physical stresses associated with using the PC for extended periods of time. These ergonomic keyboards come in many different shapes and sizes, but they have all been designed with the intention of reducing the likelihood of repetitive stress injuries to nerves, muscles, tendons, etc. They really can make using a keyboard quite a bit more comfortable for those of us who are prone to these sorts of injuries.

Another type of touch input device is the mouse. The mouse is used as a pointing and selecting device, rather than a data entry device. This means that you do not use the mouse to enter data; you use it to position the cursor, or select existing data and options from program menus. To use the mouse, you roll the mouse on your desktop. As the mouse moves, it moves the cursor on your screen.

A computing fixture for a very long time, the mouse has become such a valuable tool that most PC users cannot imagine functioning without it. Far removed from the oval shaped, two-button mouse of old, some of the latest innovations in mouse technology have really added to the functionality of this device. Some manufacturers have created models with up to five buttons; a wheel for scrolling through lists, documents and web pages; track balls on the top for moving the cursor around the screen, instead of having to move the mouse around on a pad; special designs for those who use a mouse to play computer games; and a huge variety of innovative ergonomic designs to make them more comfortable to use. Wireless infra-red connections, lasers replacing the ball, and software utilities for fine-tuning their performance are just a few of the more recent additions that have been made to the good old mouse.

The graphics tablet is another type of touch input device. This type of device uses a special pen and pad. As an image or handwriting is drawn on the pad, the image is transferred into the memory of the computer. Graphics tablets are often used by artists, architects, designers and other professionals where the ability to modify a drawing is important. For example, a graphic artist might use the drawing pad to sketch the design for an advertisement. The artist could then use the computer to add special effects to the drawing, test different colors, rotate the drawing or combine several drawings together.

Visual (or Optical) Input Devices: These devices enter data by "looking" at the raw data, recognizing the image it sees, and translating the image into electronic signals that the computer can understand. Common visual input devices are scanners and digital cameras.

Scanners work much like copiers. They take the text or graphics that are being scanning and store the information in the computer's memory (that is, the image is passed into the computer's memory as a stream of electronic signals). The device driver then tells the scanner exactly how to organize the electronic signals for the computer systems.

The most commonly-used page scanners look like a small desktop copier. These scanners can input an entire page of graphics or text into the computer at once. The page to be scanned is placed on the bed of the scanner, and the light beam is passed under the page. Text and written words can be scanned to avoid retyping information from a printed document, such as a book. Scanned graphics and text can then be combined to create newsletters, catalogs or almost anything else imaginable.

Digital cameras and digital video cameras are similar to conventional cameras in many respects: you or your camera still have to focus, make the correct exposure, and you still need a flash in low light. However, the digital imaging technology that these cameras utilize does not use regular film, avoiding expensive processing and printing (and waiting).

Sound (or Audio) Input Devices: These devices "listen" to sounds and record them into signals. A common sound device is a microphone.

Printers are the most common devices that produce output that you can touch, often referred to as hardcopy. There are hundreds of different makes, models and styles of printers. Each type has its advantages and disadvantages.

The computer display monitor is the most common visual output device and is one of the key factors that define your PC experience. For example, the resolution on a CRT, or Cathode Ray Tube (just like your TV set), monitor can be adjusted to suit your personal taste. If you like your images, icons, windows, etc. nice and big for easy reading, you can set a low resolution (640x480 or 800x600, for example). If you prefer to have the ability to view multiple windows and/or you want to reduce the amount of scrolling necessary to view an entire document or Web page, you are free to adjust the resolution all the way up to 1600x1200 and beyond, if your particular monitor and graphics accelerator will support it.

Many technological advances have been made in monitors over the last few years. CRT monitors are now sporting larger viewing areas. Not only are there the standard 15-inch monitors, there are also larger 17", 19", 21" and 22" models available at reasonable prices. There are also "flat screen" CRT monitors. Although these monitors are not truly flat (this is impossible with CRT technology), they are closer than ever. Image distortion and glare from nearby light sources are greatly reduced in the "flat screen" format.

Speakers are the most common audio output devices. Speakers take electronic signals and convert them into sound. PC speakers have been around for a long time and, in one form or another, are now pretty much standard equipment on every PC. All computers have small, simple internal speakers that give you beeps as you complete tasks or make errors. The addition of external speakers to PC's, a CD player and the proper software, or appropriate sound files (.mid, .wav, .mp3), really unleashed the potential for a very full and entertaining multi-media experience.

This is not to say that the everyday "two tiny speakers sitting beside the monitor" is the only option out there. (Far from it, as a matter of fact.) There are two-way, three-way, and even five-way, speaker systems available to turn your PC into everything from a simple radio to play some quiet music while you work, to a one-person cinema with full on surround sound for watching DVD movies, or into a smashing, crashing, exploding, bass-booming battlefield for gaming at its most intense. Adding a good set of speakers to your PC can indeed be one of the most cost-effective ways to get a lot more out of the time you spend sitting in front of it.

Adding Devices to Your Computer

Expanding or upgrading your PC doesn't always involve opening it up and messing with the insides. You can add functionality to your PC by plugging devices into an external port. Printers, scanners, digital cameras, joysticks and/or three-way speaker systems are all excellent external additions. Each of these items can add a whole new dimension to your PC experience.

The great thing about these external devices is that they are very easy to add. Generally, all that is required is to turn your PC off (this is not necessary when connecting through a USB port); plug the new device into an existing external port; turn your PC back on; follow the instructions that are presented when Windows detects the new device; and then install whatever software (such as a driver) that may be needed for the device.

When you look at the back of the system unit, you will see several receptacles, which are called ports. These ports allow you to connect a number of external devices to the computer, including printers, modems, keyboards and mice. Regardless of the type of ports you have, the function each performs is basically the same: Moving data, or information, from an external device into the PC for processing; or from your PC out to an external device. There are three different kinds of ports: parallel, serial and Universal Serial Bus (or USB).

Parallel ports send several bits at a time to the device, usually a printer. In this way, the port can transfer an entire byte or character (that is, eight bits) at a time. This provides very fast information transfer. The most common use of the parallel port is to connect a printer to the computer.

Serial ports transmit data one bit at a time. To send one byte (or eight bits), it must send each bit individually. This means the serial port will normally operate slower than the parallel port. Serial ports are commonly used to connect a mouse or modem to the computer.

USB ports support data transfer rates of 480 Mbps (or 480 million bits per second). A single USB port can be used to connect many peripheral devices, such as mice, modems, and keyboards. If you have an older PC, you may only have parallel and serial ports. USB ports are a fairly new feature, so if your PC is getting on in age it may not have USB capability. It wasn't until 1998 that USB became widespread, but it is expected to completely replace parallel and serial ports.

Network cards (Network Interface Card, or NIC) connect your PC to other PC's, high speed modems and a growing number of household electronics.  The primary use of a network card is to connect your PC to another one. So you end up with your own little internet, or intranet as they are known.

If you have an old PC with no network card, and intend to buy a new replacement PC, treat the old one to a network card, and see how beneficial it becomes.  You can share an internet connection, transfer files, even play games, simply and extremely fast.  All by purchasing a cheap network card. Then you are the master of your own home network.

If you were wondering, the actual physical connection is merely a piece of cable. It wouldn't be computers without lots of tangled wires would it?

How a home network works?

There are a couple of things to keep in mind when adding external devices. The first and most important thing you need to do is to be sure to carefully check the minimum system requirements of any new device that you are thinking of purchasing. It is not very much fun to get a spiffy new piece of hardware home only to find out that you can't use it because your PC cannot, for any number of reasons, support it. You may also want to check to see if the documentation includes "Recommended System Requirements," in addition to the Minimum System Requirements. A system that meets the minimum requirements will be capable of using the device, but chances are that you will be able to make the most efficient use of your new device if your system meets the recommended system requirements instead.

The other really important thing to take note of is whether or not the particular type of port required by an external device you are considering is free for use. This is one of reasons why USB is so useful. If you want to add another device to your PC and the USB port is already in use, you can add a USB hub, which will allow you to attach many devices through the same port.


Personal Computer
(or PC)
Central Processing Unit
(or CPU)
Brain; Car Engine

(or Mainboard)

Random Access Memory (or RAM)
Hard Disk Drive
(HDD or C: drive)

Complete Library;
Store Room

Compact Disk-Read Only Memory
(or CD ROM or D: drive)
Floppy Disk Drive
(FDD or A: drive)
Input Devices
(such as, keyboards, scanners, microphones)
Car Steering Wheel

Output Devices
(such as, printers, monitors, speakers)

Network Card


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A (Slightly) Different Approach to Understanding Computers --

A PC is merely something that empowers the individual to do more--in the same way that owning a car enables someone. You can travel to places at any time to get things done, at your own pace, fitting it all in with your schedule. The car is not mystical, it is (believe it or not) serviceable by human beings like you and me, and it doesn't make any of it's own decisions. So it cannot run your life for you, take over the world, or start a nuclear war, just like a computer cannot do anything on it's own.

The CPU is the central processing unit, which is, in essence, the brain of the computer. It is where everything is processed and all major decisions are made. In the same way that your own brain oversees all functions of the body, a CPU does the same. The speed of the CPU depends on how many instructions it can process within a given amount of time. (And I'm sure you all know people that seem to have their own personal processors that are slower than most.) This is similar with computers: A slow speed processor is extremely easy to spot, and should be avoided if possible. Unlike a brain, however, the CPU costs considerably more.

The motherboard is like a body. It is a physical structure to house all the necessary components, and is vital to ensure everything can function properly. It is essential, in the same way that your skeleton and skin are, because without both of those, you would just be a huge mostly red, mess (whereas, a computer would be a mostly green and black mess).

RAM -- Memory, or Random Access Memory, if you are going to be proper about it. It is the equivalent of short-term memory. It is most commonly confused with hard drive space, which is more like long-term memory, or a full library. The amount of RAM you have decides how much you can remember (seems obvious, right?).

You need to go to the store and have enough memory (RAM) to remember 10 items. If you have to get more than 10 items, you are going to have to have to remember it somehow. So you decide to write down all the other items on your shopping list. While shopping, you zip from aisle to aisle industriously grabbing all the reasonably priced goods on your list. As soon as you reach the limit of your memory, you have to go to your list for guidance. You then have to cope with reading the list and risking crashing into the family of twelve (who always insist on shopping via the 'Block the Aisle' Method), because you are busy trying to decipher your hastily scribbled shopping list and not looking out for the Partridge family shopper. This then slows down, the up to now, great shopping experience.

RAM is only used in the short term. When you power off, it is lost. So when you emerge triumphant from your shopping expedition, and stride purposefully towards your completely non-mystical car, you are already losing the memory of what you needed in the market. By the time you crawl into bed, you have had many other things on your mind during your day, which you needed to attend to, and they all had their time at the front of your mind. So, during your time spent at a computer, there will be many things passing through its RAM that it needs to remember for the moment, but not forever. Because if it does need to remember them longer, it writes them down somewhere safe.

Which takes us to the hard drive (Hard Disk Drive or HDD). This is a more permanent storage of information for your computer. It is the place your computer goes when it doesn't know something already. As a person is born without knowing anything other than how to breathe, walk, eat, sleep, and play Super Mario, it's the same with a computer. Each time you switch on the power, the computer only knows how to power up and check that all its bits and pieces are plugged together in a fairly comfortable way. Once the "Oh, I'm awake" phase has been completed, the computer looks to its hard drive for guidance, in the same way that a person would consult a diary to find out what they have to do that day. The computer uses the hard drive all day long, for nearly every function it performs. As you consult a stop sign to tell you when to stop, a clock to know the time, a bill to know the amount you owe to the gas company, or something as complex as a book to teach you knitting, the computer looks to its hard drive. Everything it ever knows (and has known, too, sometimes) is there.

A hard drive looks much like a record player inside, except this one is able to write things on its disk as well as read them. It is a permanent fixture of your computer and it cannot function in any meaningful capacity without it. The hard drive is where you save all your work, like a huge library with a staggering amount of space to put "stuff" (but not nearly as boring).

CD-ROMs (or Compact Disc Read Only Memory) are much smaller versions of your hard disk drive, and they are not essential components of your computer. They are exactly like music CDs, and contain information that your computer can read. You put them into the computer when you need to (usually when the computer asks you to) via a small tray, much like a music CD player mechanism. So if you have used a CD music player, you will be very familiar with CD-ROM disks for computers.  The CD-ROM Drives are being phased out of late, in favor of the similarly priced CD-RW drives, as with only a CD-ROM drive you cannot make your own CD's or save any information on them.

CD-RW Drive* (or Compact Disc ReWritable) are similar to CD-ROM drives but they differ in one fundamental way, in that you can put information ONTO a CD as well as read FROM it.  The phrase "To burn a CD", means to put information on a CD.  It can be anything from computer files to audio tracks which you can play in any CD player.  So you place a disk into the drive and then put anything you like on it, very similar to your internal hard drive.

DVD-RW Drive* (or Digital Versatile Disc ReWritable) are the same as above, but for DVD's instead of CD's.  These DVD drives can deal with normal CD's, CD-RW disks AND DVD disks, so you can play DVD movies on them too, even make your own DVD's!  Apart from being able to make DVD's the capacity of a DVD disk is much greater than a CD, so you can fit more on it.

*To use these devices effectively make sure you get the correct disks for each one.  DVD Drives can write and play any disk, but CD-RW drives can only read and write CD's.  Also you must make sure you purchase CD's or DVD's that you CAN put information on (or burn), as you cannot simply write over any old CD, or DVD you may already have.

Floppy Disk Drive (or FDD) -- Another library, a small bookstore, a very small version of your hard drive or CD's. (They are over 450 times smaller than a CD-ROM, and something approaching 15,000 times smaller than a modestly-sized hard drive.) If you indeed kept a store of every life experience in some massive archive, the floppy disk is like the shopping list from April 17th 1974. They are becoming more and more obsolete, and their only place in computers today is to serve as a "floppy" companion to the "hard" puns, that always circulate during these types of discussions.  As of lately manufacturers are beginning to phase out floppy disk drives as other media is becoming so cheap.

Input Device(s) are any device that puts data INTO your computer: You speak to them. Their ears pick up the sound. You touch them on their skin. Their nerves feel it…and it's noted deep inside the brain. (Would be equivalent to the stimulus a person receives during a normal day.) A car steering wheel is an input device for a car. Keyboards, mice, graphics tablets, microphones, are all ways for you to put data INTO your computer. They are the eyes and ears of a computer, but the computer being all smug has lots more ways to get input. There are a million (give or take a few) gadgets you can buy, that put information INTO your computer.

Output Devices -- They are what you need to be able to interpret what the computer is doing or has done. A monitor is one example. You see there on the screen what the computer is doing. (In much the same way a woman only has to look at a man to see what he is thinking). Speakers are output devices. Printers are output devices. If you ask someone to draw a picture, the output device would be the pencil and paper.

No computer speaks "phone line" and no phone line speaks "computer." And that's where the modem comes in. Modems are bi-lingual--they speak "phone line" and they also speak "computer." Without a modem, the phone line would be a French fast-food associate, taking orders for the whole Hungarian army. In other words, no one would get any food. The Hungarian army (your computer) needs food (information), and the French person (phone line) is how it's going to get it. So the Hungarians get a modem in to translate their request for food. The modem gives the request to the French person, who then sends that request off to the kitchen (the Internet) for (food) processing. When the required food (info) returns, the modem collects it from the French person, and checks it has all the necessary sauces and cutlery, and passes it on to the Hungarians.

This may still seem a little confusing, but if you stop for a moment and give it a little thought, you will come to see that computers are NOWHERE NEAR as complicated as sales people or network admins would have you believe.


So you think you are ready for your own personal computer system and are considering buying one? Have you ever taken a look at some advertisements and wondered what all those numbers and abbreviations meant? Some ads and salespeople will imply that purchasing computer systems is tantamount to "brain surgery." This section will help demystify some of that, and provide you with the basic knowledge you need to be an informed consumer.

First, think about who will be using it and what they will likely use it for. Typically, a family computer will be used for varied reasons. Younger members may want to play video games or do online gaming, and claim they will use it to do their homework (thereby, increasing the likelihood that you will get the computer). Other members may wish to play music or movies, want to "surf the Net," or see it simply as a productivity tool. No matter what you think now, however, keep in mind that computers and the Internet are facilitating an ever-expanding range of everyday activities. Only by using it, will you come to understand how these tools will help and entertain you.

Most importantly, consider your budget. The market has become so competitive that you can purchase an outstanding computer system for under $1,000. Do your homework and then shop around for the best deal that meets your needs (and not the needs of the salesperson) now and in the future

(In order of importance)
Key Factors
Basic Considerations
Central Processing Unit (or CPU) Speed 1.4Ghz and upwards
Random Access Memory (or RAM) Amount 128-512 Megabytes (or MBs)
Hard Drive (or HDD) Size/Capacity 20 Gigabytes (or GBs) and above
Graphics Card Purpose Will it be used for multimedia, such as movies and games, or not?
CD-ROM, CD-RW or DVD-RW Drive(s) Purpose/Budget CD drives do not play movies; DVD drives play movies, plus everything else a CD drive does
Monitor Size 17" or larger 17" or larger; Is this included with system?
Sound Card Quality/Purpose Budget
Modem Speed Minimum: 56K Dial-Up
Mouse Ergonomics Budget
Keyboard Ergonomics Budget; Is this included with system?
Floppy Drive (or FDD) None Standard: 3.5" 1.44 MB
Speakers Personal Preference Budget
Network Card Existence Speed - 100Mbps
Preloaded Software Purpose/System Compatibility Budget; Minimum requirement: operating system (OS) software, such as Windows XP or above

When you purchase any input/output device, you should ask the following questions:

1. Are all required cables included?
2. Can I use an existing port that is currently on my computer system, or will I need an add-on board or controller card? If an additional board or card is required, is it included with the input device?
3. Is the device driver software for the device included? If not, is it available online at no additional cost?

Typing Test
Practice Using the Mouse
Check Yourself: Computer Hardware
(Part 1)
Check Yourself: Computer Hardware (Part 2)


Every piece of hardware in your computer, needs to have what is called a driver.  A bit of software on a disk, or downloaded from the internet.  This is a way of telling the piece of hardware what to do.  In fact the term "driver" is much like the driver of a car, in that on it's own, a car would simply sit there and not go very far. Even just releasing the brakes would not result in a very productive (but probably expensive) journey. So a computer is the same. Things not working quite as you would expect, are often due to wrong, or missing driver files. An example of a great one, is to install the wrong printer driver, then try printing a couple of pages. Quite often the printer will print a couple of lines of gibberish at the top of about 300 pages! This shows how important the correct driver can be. As a rule, the company that made your piece of hardware, usually has the driver file on a disk included in the package when you purchase it. They constantly update drivers for hardware and so it is advisable to check that you are using the latest drivers for your equipment, by visiting their websites. This can make dramatic improvements at times, although on occasion it messes up something else. So sometimes, if it ain't broke, don't fix it.

Drivers function very much behind the scenes, so most of the time you should not be aware they are there at all.

If you feel that you need to have the latest version of the driver to make whatever it is function that bit better (graphics card, monitor, printer etc), then try to make sure you have a copy of the previous driver just in case the new one causes problems. These problems can range from hardly noticeable, to completely stopping the PC working. If you are in any doubt as to the usefulness of updating a driver you should check with the manufacturer about what the driver update actually solves, and any issues arising from it. On their sites they should have information about the newer drivers they supply.

Lastly, no hardware manufacturers charge anything for their updated drivers (unless perhaps if you ask them to mail you the disk of course). It is a way of keeping you from having to phone them to ask why something isn't quite right. Any manufacturer worth doing business with, should have sections of their websites devoted to you the purchaser, helping yourself, rather than bothering an expensive call center for the same question a million times a day.

Which leads us nicely to the next section. Software, onwards to section 2.

Last updated Sep 9 2003


(C) I-LEAD 2002