Main Parts 4

Zip Disc


A Zip disc is like a more recent version of the floppy disk, the main difference being that a single Zip disc can hold up to 250 Mbytes of data. They also offer increased speed compared to the old floppy disk.



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Hard (Fixed) Disk



Hard disks are the main, large data storage area within your computer. Hard disks are used to store your operating system, your application programs (i.e. your word processor, games etc) and your data. They are much faster than CD-ROMs and floppy disks and can also hold much more data.


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The Monitor




An Output device. The monitor is the TV type screen that you view your programs on. They are supplied in different sizes, common sizes range from 15" to 21" screens. You should be aware that poor quality or badly maintained monitors could harm your eyesight


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Additional items or cards


Many 'extra' components can easily be fitted to your computer, which has the advantage of making the computer 'upgradeable' as newer and better hardware comes along.




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Sound cards and speakers

Many computers are now supplied with sound cards and speakers that mean that when you run 'multi-media' programs, you can listen to sounds that are played back via your computer. If you have a microphone and suitable software, you can also record sounds. You can even purchase special software that will allow you to talk to your computer and get the computer to type the words you have spoken on your screen. In time, this type of software may replace the keyboard.

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Main Parts 3

The Keyboard


An Input device. The keyboard allows you to type information into the computer. It has evolved over the years and many people now use a Microsoft style keyboard, which has additional keys designed to make Microsoft Windows easierto use.



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The Mouse



An Input device. When using an operating system, such as Microsoft Windows, you use the mouse to select drop down menus, to point and click on items, to select items and to drag and drop items from one place to another




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CD-ROM
Most computers are now supplied with a CD-ROM (Compact Disc - Read Only Memory) drive. CD-ROM discs look exactly like music CDs but contain computer data instead of music. The advantage of a CD-ROM is that it can hold a vast amount of data (equivalent to the storage capacity of over 450 floppy disks). The other big advantage of CD-ROMs is that they are interchangeable. This means that you can own a range of different CD-ROMs and choose which one to insert into your CD-ROM drive.

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DVD Drives
Short for "Digital Versatile Disc". Similar to CD-ROM drives but allows you to use DVD disks, which contain vastly more information than a traditional CD-ROM disk. These also transfer the data from the disk to the computer far faster, allowing you to watch movies on your computer screen. A CD-ROM can store 650 MB of data, while a single-layer, single-sided DVD can store 4.7 GB of data. The two-layer DVD standard allows a capacity of 8.5 GB. A double-sided DVD increases the storage capacity to 17 GB (or over 25 times the data storage capacity of a CD-ROM).

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Floppy disk



Floppy disks are also known as diskettes. They are very slow compared to hard disks or CD-ROMs, and hold relatively small amounts of data (1.44 Mbytes). Sometimes people will backup (i.e. copy) important data from their hard disk to floppy disks. However, as diskettes are notoriously unreliable this is not the best way of backing up valuable data (but is better than nothing).

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Main Parts 2

ROM-BIOS

The ROM-BIOS (Read Only Memory - Basic Input Output System) chip is a special chip held on your computer's system (mother) board. It contains software that is required to make your computer work with your operating system, for instance it is responsible for copying your operating system into RAM when you switch on your computer

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Serial Port

The serial port is a socket located at the back of your computer that enables you to connect items to the computer, such as a modem. They are commonly labeled as COM1 or COM2

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Parallel Port

The parallel port is a socket located at the back of your computer that enables you to connect items to the computer, such as a printer. It is commonly labeled as LPT1 or LPT2.

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Universal Serial Bus (USB)

The Universal Serial Bus is a relatively new item within the PC. You will see one or more USB sockets at the back of the system unit, allowing you to plug in devices designed for the USB. These devices include scanners and digital cameras

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What are input devices?
Input devices allow you to input information to the computer and include things such as the keyboard and mouse.

What are output devices?
Output devices allow you to output information from the computer and include the printer and the monitor.

What is a peripheral device?
A peripheral device is any device that you can attach to your computer. Thus, you could attach a scanner or modem to the back of your system unit.

Main Parts of a Personal Computer

Know the main parts of a personal computer such as: central processing unit (CPU), hard disk, common input or output devices, types of memory. Understand the term peripheral device.

The System Unit
The "system unit" is the name given to the main PC box

that houses the various elements that go together to make up the PC.

For instance within the system unit is the computer system's motherboard,

which contains all the main components, such as the CPU. The system unit also

houses items such as the hard disk, the floppy disk and CD-ROM drives etc. System

units come in two basic varieties, the tower version, as illustrated

or a desktop version, which is designed to sit on your desk

with your monitor on top of the system unit

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The System (Mother) Board

in contained within your system unit and all the vital computer systems plug directly into the system board. The CPU is normally housed on your system board along with all the other electronic components. Other items such as the hard disk are attached to the system board, either directly or via cables. These boards are getting smaller and smaller as the components become more integrated. If you open up a modern system you will find that it is mainly full of air

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The CPU

The CPU (Central Processing Unit) is normally an Intel Pentium (or equivalent) and it is one of the most important components within your computer. It determines how fast your computer will run and is measured by its MHz speed. Thus, a 2 GHz Pentium is much faster than say a 1 GHz Pentium CPU. It is the CPU that performs all the calculations within the computer, when running programs such as word-processors, spreadsheets and databases. See page 10 for more information.

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Memory (RAM)

The RAM (Random Access Memory) within your computer is where the operating system is loaded to when you switch on your computer and also where your applications are copied to when you start an application, such as a word processor or database program. When you create data, (e.g. letters and pictures), these are initially created and held in RAM and then copied to disk when you save the data. As a rule of thumb, the more RAM you have installed in your computer the better. These days you will commonly find over 128 Megabytes of RAM installed.