1. Information Technology (IT). Information Technology – technology used to create, store, exchange, and use information in its various forms (business data, voice conversations, still images, motion pictures, multimedia presentations, and other forms,) – It's a convenient term for including both telephony and computer technology in the same word.

2. Distinguish Between Computers in Terms of Capacity, Speed, Cost, and Typical Users. Suggested Task – Draw up a simple table to make a comparison between the main types of computer Mainframe Computer Network Computer Personal Computer LaptopPDA Capacity Speed Cost Typical Users

3. 1.2 Hardware

4. Main Parts of a Personal Computer

5. The Central Processing Unit (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 GHz or MHz speed – For example, a 2.4 GHz Pentium is much faster than a 400 MHz Pentium CPU – It is the CPU that performs all the calculations within the computer

6. Speed of the CPU: -The CPU operates as a result of electronic pulses sent to it by another device on the motherboard called the clock. -The speed of a CPU is measured by the maximum number of pulses it is able to handle. This is measured in MHz (megahertz) or millions of pulses per second or GHz (gigahertz) thousands of millions of pulses per second. -A good personal computer will use a CPU with a clock speed of over 2 GHz. This means it receives 2 000 000 000 million pulses every second from the CPU. - Previously CPUs could only do one operation per pulse

7. Parts of the CPU There are three main components to the CPU: Control unit: Responsible for loading the individual instructions that. These instructions are in a language called machine code. Machine code is a pattern of ones and zeros. The control unit also has the task of getting the data needed by the instructions and returning the results of the processing after the instruction has been executed. Arithmetic-logic unit: The ALU is responsible for carrying out arithmetic operations such as addition and subtraction as well as logical decisions such as whether one number is bigger than another. All programs consist of complex sets of arithmetic and logical operations.

8. Parts of the CPU On-board cache memory: Because the CPU can perform its operations much faster than data can be transferred from RAM, many CPUs have on-board cache memory. This is memory that the control unit can access very quickly and use for intermediate storage

9. Memory

10. Different Types of Computer Memory RAM - Random Access Memory – The main 'working' memory used by the computer – When the operating system loads from disk when you first switch on the computer, it is copied into RAM – As a rough rule, a Microsoft Windows based computer will operate faster if you install more RAM. Data and programs stored in RAM are volatile (i.e. the information is lost when you switch off the computer)

11. ROM – Read Only Memory – Read Only Memory (ROM) as the name suggests is a special type of memory chip that holds software that can be read but not written to – A good example is the ROM-BIOS chip, which contains read-only software – Often network cards and video cards also contain ROM chips

12. comparing RAM and ROM. ROMRAM Stores certain fixed routines such as the boot-up routines Store the currently active programs and their data Function ROM is non-volatile: When the computer is switched off, the contents are not lost. RAM is volatile: When the computer is switched off, the contents are lost. Volatility The contents of ROM cannot be changed or deleted. The contents of RAM can be changed or deleted. Changeable

13. How Computer Memory Is Measured Bit – All computers work on a binary numbering system, i.e. they process data in ones or zeros. This 1 or 0 level of storage is called a bit Byte – A byte consists of eight bits

14. How Computer Memory Is Measured Byte – A byte consists of eight bits Kilobyte – A kilobyte (KB) consists of 1024 bytes Megabyte – A megabyte (MB) consists of 1024 kilobytes Gigabyte – A gigabyte (GB) consists of 1024 megabytes Terabyte – A terabyte (TB) consists of 1024 gigabytes

15. Relate computer memory measurements to characters, files and directories/folders File size – Each byte represents a different character such as letters of the alphabet, numbers, punctuation marks and blank space – A document such as a letter containing 250 of the above characters would have a file size of 250 bytes – A floppy disk of capacity 1.4MB could hold 1 400 000 characters – say, 200 000 words – a whole book! – The size of a directory (or folder ) would be found by adding up the sizes of the files contained within it – Sizes of files and folders are easily found in Windows by using a right mouse click on the icon and examining Properties

16. Byte – A byte consists of eight bits – Each bit can be ‘on’ or ‘off’ (1 or 0) – This gives rise to a total of 256 possible combinations ( 2 x 2 x 2 x 2 x 2 x 2 x 2 x 2 = 256 ) – Each byte represents a different character such as letters of the alphabet, numbers, punctuation marks and blank space – These make up the Character Set – A selection of the 256 characters in the set is displayed on the keyboard, depending on the particular language being used

17. 1.2.6 Storage Devices

18. : The Hard Disk Hard disks are the main, large data storage area within your computer They 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

19. Compare Memory Storage Devices Hard Disk Speed: – Very fast! – The speed of a hard disk is often quoted as "average access time" speed, measured in milliseconds. The smaller this number the faster the disk. Capacity: – Enormous! Often in excess of 80 Gigabytes. A Gigabyte is equivalent to 1024 Megabytes. Cost: – Hard disks costs are falling rapidly and normally represent the cheapest way of storing data.

20. types of hard disk A hard disk drive can be internal or external. An internal drive is housed inside the main unit and is connected directly to the motherboard of the computer. -An external drive is housed inside a special caddy which connects to the computer through one of its ports -An external hard drive is a good backup medium and allows large quantities of data to be stored. these drives provide a useful way of transferring data between computers that are not connected through a network

21. 1.1.4 Computer Performance

22. 1.1.4.1 Know Some of the Factors That Impact on a Computer's Performance  CPU speed  RAM size  Hard disk speed and capacity  Number of applications running