2. Introductory Computer Concepts

3. Hardware refers to the physical components of a computer system. Central processing unit(CPU) Main memory Input unit Output unit Backing storage unit Communication unit

4. Components of a computer system Input unitMain MemoryOutput unit Central processing unit Backing storage unit Communication unit

5. Input Unit Data are input through the input device. Put the data into a form that is acceptable to the computer.

6. Input Unit Keyboard Mouse Scanner …

7. Main memory Stores data and programs to carry out processing. Main Memory RAMROM

8. RAM Random access memory. data can be read from or written to RAM. data is stored temporarily. RAM is volatile, when power is off, all the data in ram will be lost.

9. ROM oRead only memory data can only be read from the ROM. overwritten is not allowed. data is stored permanently. ROM is non-volatile. when the power is off, data in ROM remain unaffected.

10. Output unit results are output by the output device in a form that can be understood by humans. Examples: Printer Monitor …

11. Why do we need Backing Storage unit? data in the main memory(except in the ROM) are lost when the machine is switched off. main memory is very expensive. data may be so large that it is impossible for the main memory to hold all the data.

12. Backing Storage unit Floppy disk Hard disk CD …

13. Communication unit Connects the computer system to another so that data and programs may be sent to and from the computer. Example: Modem

14. Central Processing unit Carries out all the processing. Executes the instructions to perform a particular task. Coordinates the interaction of all the other hardware components. It is contained on a microprocessor chip.

15. Software programs to tell the computer how to do its work. Software Applications Software System Software

16. Application Software end-user software Microsoft office Paint PhotoShop Etc.

17. Application Software Packaged Software Custom-made Software PurposeGeneral purpose program Specific purpose program TargetAll organizations A particular organization CostCheaperExpensive ExampleMicrosoft OfficeGenerate academic reports in GHS.

18. System Software “ Background program ” to make sure that the computer hardware carries out the intended tasks. Example: Operating System

19. Types of Computer Microcomputer Minicomputer Mainframe SuperComputer