Parts of a computer

Desktop computer system

If you use a desktop computer, you might already know that there isn't any single part called the "computer." A computer is really a system of many parts working together. The physical parts, which you can see and touch, are collectively called hardware. (Software, on the other hand, refers to the instructions, or programs, that tell the hardware what to do.

The illustration below shows the most common hardware in a desktop computer system. Your system may look a little different, but it probably has most of these parts. A laptop computer has similar parts but combines them into a single notebook-sized package.

Let's take a look at each of these parts.

System unit

The system unit is the core of a computer system. Usually it's a rectangular box placed on or underneath your desk. Inside this box are many electronic components that process information. The most important of these components is the central processing unit (CPU), or microprocessor, which acts as the "brain" of your computer. Another component is random access memory (RAM), which temporarily stores information that the CPU uses while the computer is on. The information stored in RAM is erased when the computer is turned off.

Almost every other part of your computer connects to the system unit using cables. The cables plug into specific ports (openings), typically on the back of the system unit. Hardware that is not part of the system unit is sometimes called a peripheral device or device.

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Storage

Your computer has one or more disk drives—devices that store information on a metal or plastic disk. The disk preserves the information even when your computer is turned off.

Hard disk drive

Your computer's hard disk drive stores information on a hard disk, a rigid platter or stack of platters with a magnetic surface. Because hard disks can hold massive amounts of information, they usually serve as your computer's primary means of storage, holding almost all of your programs and files. The hard disk drive is normally located inside the system unit.

CD and DVD drives

Nearly all computers today come equipped with a CD or DVD drive, usually located on the front of the system unit. CD drives use lasers to read (retrieve) data from a CD, and many CD drives can also write (record) data onto CDs. If you have a recordable disk drive, you can store copies of your files on blank CDs. You can also use a CD drive to play music CDs on your computer.

CD

DVD drives can do everything that CD drives can, plus read DVDs. If you have a DVD drive, you can watch movies on your computer. Many DVD drives can record data onto blank DVDs.

Tip

If you have a recordable CD or DVD drive, periodically back up (copy) your important files to CDs or DVDs. That way, if your hard disk ever fails, you won't lose your data.

Floppy disk drive

Floppy disk drives store information on floppy disks, also called floppies or diskettes. Compared to CDs and DVDs, floppy disks can store only a small amount of data. They also retrieve information more slowly and are more prone to damage. For these reasons, floppy disk drives are less popular than they used to be, although some computers still include them.

Why are floppy disks "floppy"? Even though the outside is made of hard plastic, that's just the sleeve. The disk inside is made of a thin, flexible vinyl material.

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Mouse

A mouse is a small device used to point to and select items on your computer screen. Although mice come in many shapes, the typical mouse does look a bit like an actual mouse. It's small, oblong, and connected to the system unit by a long wire that resembles a tail. Some newer mice are wireless.

A mouse usually has two buttons: a primary button (usually the left button) and a secondary button. Many mice also have a wheel between the two buttons, which allows you to scroll smoothly through screens of information.

When you move the mouse with your hand, a pointer on your screen moves in the same direction. (The pointer's appearance might change depending on where it's positioned on your screen.) When you want to select an item, you point to the item and then click (press and release) the primary button. Pointing and clicking with your mouse is the main way to interact with your computer. For more information, see Using your mouse.

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Keyboard

A keyboard is used mainly for typing text into your computer. Like the keyboard on a typewriter, it has keys for letters and numbers, but it also has special keys:

• The function keys, found on the top row, perform different functions depending on where they are used.
• The numeric keypad, located on the right side of most keyboards, allows you to enter numbers quickly.
• The navigation keys, such as the arrow keys, allow you to move your position within a document or webpage

You can also use your keyboard to perform many of the same tasks you can perform with a mouse. For more information, see Using your keyboard.

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Monitor

LCD monitor (left), CRT monitor(right)

A monitor displays information in visual form, using text and graphics. The portion of the monitor that displays the information is called the screen. Like a television screen, a computer screen can show still or moving pictures.

There are two basic types of monitors: CRT (cathode ray tube) monitors and LCD (liquid crystal display) monitors. Both types produce sharp images, but LCD monitors have the advantage of being much thinner and lighter. CRT monitors, however, are generally more affordable.

LCD monitor (left); CRT monitor (right)

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Printer

Inkjek printer(left), laser printer(right)

A printer transfers data from a computer onto paper. You don't need a printer to use your computer, but having one allows you to print e‑mail, cards, invitations, announcements, and other materials. Many people also like being able to print their own photos at home.

The two main types of printers are inkjet printers and laser printers. Inkjet printers are the most popular printers for the home. They can print in black and white or in full color and can produce high-quality photographs when used with special paper. Laser printers are faster and generally better able to handle heavy use.

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Speakers

Computer Speakers

Speakers are used to play sound. They may be built into the system unit or connected with cables. Speakers allow you to listen to music and hear sound effects from your computer.

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Modem

Cable modem

To connect your computer to the Internet, you need a modem. A modem is a device that sends and receives computer information over a telephone line or high-speed cable. Modems are sometimes built into the system unit, but higher-speed modems are usually separate components.

Basic information on computer maintanance

Certain basic computer maintenance and housekeeping chores need to be done by all home PC users. Procedures are discussed for this basic task.

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A large fraction of the population now uses a computer at home. Unfortunately, large numbers of these home users do not seem to understand that a computer is a high-maintenance device that demands much more routine care than the usual household appliances. Also, many home users are unwilling or unable to spend the time and effort required to learn some elementary knowledge about how computers function. There is no question that many ordinary home PC users would benefit greatly from just a modicum of basic knowledge on the subject but I also know from experience that there is a lot of inertia and considerable reluctance to learn that basic knowledge.

It’s a shame because I have encountered many instances where a PC user tells me about a problem that could have been fixed in 10 or 15 minutes with a little basic knowledge. Instead he or she loses many days waiting for a friend or relative to fix it or spends a fair amount of money for a technician. (Or in some cases even buys a new computer.) What I will try to do in this article is to outline the basic things that I think would be of use to all PC users whatever their technical background. True, you could go through life and never need any of this stuff. On the other hand, a little preparation might just save you from a peck of trouble.

Updating anti-virus protection

Most computers nowadays come with an anti-virus program. However, many people fail to keep their database of virus definitions updated. All the major anti-virus programs come with an update feature that should be used regularly. Having to update daily is now routine since new malware appears constantly.(Note that anti-virus programs actually protect against a variety of malware, not just viruses.) Unfortunately, the major companies no longer provide unlimited updates but have started charging after one year's (or even less) usage. Many people let their subscriptions expire. If you are unwilling to pay for protection, there are free programs. The excellent site Tech Support Alert keeps tabs on the best free programs.

Updating anti-spyware protection

These days, anti-virus programs are insufficient to guard against all malware. Anti-spyware programs are also needed and like anti-virus programs must be updated regularly. For freeware in this area, also go to Tech Support Alert. Those who can afford the annual expense of a subscription should consider a security suites from one of the major companies. See the links at Safety on the Internet.

Preparing for disaster

Unfortunately, hard drive failure is not all that uncommon. If it occurs, everything that is on the drive is lost (unless you resort to an expensive recovery service). Also, if you do get a virus, a lot of your disk may be wiped out. Or, in a variety of other ways, files may be corrupted or lost. Botched software installations, system crashes, or just plain carelessness can lose valuable data. Thus, backups are essential. Ideally, the whole system should be backed up to some external storage device. At a minimum, all files such as passwords, favorite places, address books, financial and tax records, important documents and correspondence (including e-mail), and any other personal data that has more than transitory value should be backed up to some place other than your hard drive. Windows XP System Restore and programs like GoBack are not sufficient since they write to the main disk.
There are a variety of strategies for regular backup. I prefer an external USB drive and one of the imaging programs like Norton Ghost or Acronis True Image. However, since many PC users will balk at anything that isn't as simple as possible, I have also written an article on some minimum backup procedures. Those who are willing to invest in a more complete strategy can read this article for detailed ideas. I do not personally care for it but Windows XP comes with software for backup. I have described its use on another page.

Using System Restore

It does not replace a regular backup procedure but the Windows XP accessory System Restore is a valuable tool that can remedy many common problems. All PC users should learn how to use it and its use is described on a separate page. There is also a Macromedia Flash tutorial on a sister site.

Disk Maintenance

Making sure that your hard drives are healthy is an important part of maintenance. The Windows tool Chkdsk should be run periodically to check file and folder structures as well as the disk sectors. Its use is described here.
Windows XP does not seem to need defragmenting as often as previous Windows systems but regular maintenance should still include running the system tool Disk Defragmenter. It use is described on this page. and a tutorial is at this link.

File Maintenance

A certain amount of file housekeeping will help your system to be more efficient and stable. Windows programs use a lot of temporary files, which can accumulate at an alarming rate. In particular, the folders Temporary Internet Files and certain Temp folders can really build up. Keeping these and some other system folders clean is discussed on this page. Making use of the Windows system tool Disk Cleanup is described here.