Computer Hardware & Software 1

What is a computer?

A computer is an electronic device that processes data, following a set of instructions to produce information which it can output or store for future use.

Why do we use computers

• For their data-processing speed.
  Computers are very fast. They can perform billions of operations per second. With this speed comes the power to undertake many different tasks such as predicting weather forecast, performing scientific research and producing thousands of bills for utility companies.
• For their data-processing accuracy.
  Computers are very accurate. Errors occur only if there is an error in the way hardware and software have been sset up or if there is an error in the data that has been input.
• For storing large amounts of information.
  There are many types of compputer storage media that can be used to store large volumes of data and information. For example CD-ROM, Hard Disk Drives, Flash Drives & etc..
• For their ability to work continuously.
  Computers can work continuously for very long periods, only stopping for upgrades or maintenance checks.

Hardware & Software

A computer system consists of both hardware and software.
Hardware is all the physical components/parts of the computer system. Hardware components that are connected to the computer are also called peripherals. Examples of hardware are keyboard, VDU(Visual Display Unit), mouse, speaker, hard drives, printer, etc....

Software is a set of instructions that the computer needs to carry out its tasks. These devices are also known as a program. For example if you want to type a letter, you would use Ms Office Word.

What is a computer system?

A combination of hardware and software. Neither one is much use without the other, since without hardware yo would not be able to run the software and with out software you would just have an expensive piece of equipment that does nothing.

Categories of Computer Hardware

There are four main categories of computer hardware:

1. The Central Processing Unit (CPU)
2. Storage devices (Both Primary and Secondary)
3. Input devices
4. Output devices

The Central Processing Unit

The part of the computer that does the processing. It also controls the transfer of data between memory and the other devices that make up the computer system. The CPU consists of:

1. The Control Unit (CU)
2. The Arithmetic Logic Unit (ALU)
3. Cache/Registers

The Control Unit (CU)

The CU is a part of the CPU which control the operations of the CPU. It is used to:

1. To direct the operation of the interrnal processor components
2. To control the flow of programs and data in and out of the primary memory (main memory)
3. To read and interpret program instructions
4. To control the flow of information to and from all the components of the computer. Example I/O devices (Input/Output Devices).

The Arithmetic Logic Unit (ALU)

The part of the CPU that does the following:

1. Performs arithmetic operations. these operations include adition, subtraction, division, multiplication, etc...
2. Performs logical operations. These operations include reasoning and performing the comparisons necessary to make decisions.

Cache/Registers

A small but very fast areas of memory in the CPU.