Hardware

Hardware is the collective name for the physical components of a computer system.

CPU

The processor or CPU (central processing unit) is the main computer microchip that makes the computer work. CPUs are described by their speed in gigahertz (GHz). The higher the number of GHz the faster the CPU can work. However, the speed of the computer doesn't rely on the speed of the CPU only. The type of bus, RAM, hard drive, video card and cache will affect the computer's overall speed. CPUs range from 1.5 GHz to 3.2 GHz. There are several different brands available so ask the seller to compare the different brands for you.

Motherboard

The motherboard is the main circuit board in the computer and all the computer's parts like the CPU, RAM, expansion cards, ports, the Basic Input Output System (BIOS) and slots are attached to it. Slots let you add expansion cards to the computer. Expansion cards are circuit boards that add functions to the computer such as a sound card, video card or game controllers and they are designed to complement the buses and slots.

Ports are sockets at the back and front of the computer that allow the connection of peripheral devices. Firewire, USB, serial ports or comm ports and RS-232 ports are used to connect a mouse, modem or digital camera. Parallel ports connect devices like printers and scanners.

A USB (Universal Serial Port) is becoming the standard as it is a one size fits all connection to let you add and unplug peripheral devices, including printers, scanners, mice, joysticks, flight yokes, digital cameras, webcams, scientific data acquisition devices, modems, speakers, MP3 players, telephones, video phones, storage, devices such as zip drives and network connections.

FireWire is another port that is becoming more popular as it supports a variety of devices that handle lots of data and different types of digital signals, such as compressed video, digitised audio, MIDI , and device control commands.

You can connect scanners, digital camcorders, MP3 players, high-speed storage devices, CD ROM drives, DVD players, camcorders, digital audio equipment and other devices to your computer.

Buses

A bus moves bits of information to different parts of the computer. The speed of the bus is measured in bits per second or cycles per second.

RAM

Random Access Memory (RAM) is the computer's working memory. This is the area where information and software is stored and used when the computer is working. It can be compared to desk space, the bigger the desk space the more things you can put on it to work with. RAM is measured in megabytes (Mb).

To give you an idea it will take at least 128Mb of RAM to properly run Windows XP.

New computers today are usually sold with at least 256 Mb but if you want to play a lot of new games you should consider a computer with more RAM. RAM is also described in terms of how fast it can retrieve information held on it. Sometimes RAM is referred to as SD RAM or DDR RAM.

Cache

Cache is an extra memory that stores information that is used a lot. It can be attached to devices like the CPU to make the computer run faster. Cache memories are sold with anything from 256Kb to 1Mb of memory.

HDD

Hard Disk Drives (HDD) store information. They can be thought of as a filing cabinet. Information that doesn't fit on your desk space (RAM) is placed in the filing cabinet. It is important to get a computer with enough space for your software needs.

Another feature of hard disk drives is the spindle speed. The rpm will affect how fast the hard disk can retrieve information stored on it.

Upgrading is usually just a matter of installing another HDD. IDE (integrated drive electronics) also known as EIDE (enhanced integrated drive electronics), SCSI (small computer systems interface) and SCSI2 are types of hard disk. EIDE hard disks do not need special controller cards to run and are ideal for most users.

SCSI hard disks often need a special controller to run and are suitable for digital video or audio editing tasks that need the connection of several peripheral devices.

Graphics card

A video or graphics card is a circuit board that plugs into a slot in the motherboard. The graphics card is told what to do by the CPU and drives the monitor. The frequency at which the pixels are lit up is known as the refresh rate. A refresh rate of 70 Hz means that each pixel on the screen will be rewritten 70 times per second. The higher the memory (RAM) on the video card the higher the resolution and the greater the number of colours you can see. To move a lot of pixels at high speed some video cards include accelerators. These take over the work done by the CPU.

Most graphics cards today support the Video Graphics Array (VGA), Extended Graphics Array (XGA) and Ultra Extended Graphics Array (UXGA) display system standards which convert the signal from digital to analogue for transmission to the monitor. These analogue signals are delivered to the monitor through a VGA adapter. Because of the digital to analogue conversion, some picture degradation occurs.

A new standard display system has been developed to fully support the use of digital monitors called digital video interface (DVI). DVI keeps data in digital form from the computer to the monitor, virtually eliminating signal loss. If you buy a DVI monitor, make sure that you have a video adapter card that can connect to it.

Monitors

The two most common types of monitors available are the cathode ray tube (CRT) and the liquid crystal display (LCD). LCD monitors are beginning to replace CRT monitors because of their slim design and more efficient energy consumption.

Disk drives

 A floppy disk is a portable storage device. One type is a 3.5" that stores 1.44Mb (megabytes) of data. Zip disks are capable of storing up to 250Mb of data.

DVD and CD ROM

CD ROM (Compact Disk-Read only Memory) is similar to a music CD except it stores computer data. The speed that information is read from the disk is described as a multiple of the original CD ROM speed.

Today you can buy CD ROMS at 24X to 50X. Most software is provided on a CD ROM and computer packages will usually include one. You can also buy a CD Recordable (CD R) drive that can record information onto special blank disks once only. A CD RW (CD Re writeable) can write on a CD several times. DVD ROM Drive (Digital Versatile Disk) is an alternative device that allows you to read video images or movies as well as software and music.

In addition to reading, DVD burners can write or record video, images, movies, music and other software on DVD. There are several formats of DVD writing including DVD-R(G), DVD-R(A), DVD-RW and DVD+RW. Many DVD burners will read and write in multiple formats. If you are buying a DVD burner or a computer with a DVD burner, check the formats that it handles and if it is suitable for your purposes.

Keyboard

QWERTY is the standard typewriter style keyboard.

Sound cards

Sound cards allow the computer to generate sounds. This and the type of speakers included in the system can be an important feature if you play a lot of games or want to use multimedia. Ask the retailer for a sound card and speakers that best suit your needs and budget.

Modem

A modem (modulator/demodulator) makes it possible for you to connect your computer to other computers and exchange information, files etc. Modems are used for email, internet and faxes. They are described in terms of how fast they receive and transmit information such as 56Kps (kilobytes per second). The speed at which data is retrieved from the internet will also depend on the line speed provided by the Internet Service Provider (ISP).

You can connect to other computers and the internet through a dial up modem, a cable connection, wireless modem, satellite connection or through an asymmetric digital subscriber line (ADSL) connection.

Connections through cable, wireless, satellite and ADSL are commonly called broadband and are many times faster than a dial up modem connection but generally cost more for the service. Not all broadband services are available everywhere so check with internet service providers (ISPs) for services they provide in your area and the type of modem you will require.

Routers

If you own more than one computer, you may wish to purchase a router that will allow you to network your computers and share files, internet connection and peripheral devices such as printers and scanners. A router connects computers and controls the flow of information between them.

 

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