1. Software; Nature, Capabilities and Limitations: describe the need for interfacing with peripherals storage devices, input and output devices and display devices; describe the need for printer and other peripheral drivers. Nature and Types of Software: describe the distinction between systems software and applications software; describe the purposes of operating systems. Describe the nature of package software, generic and specific, and of bespoke software. Describe the general characteristics of generic packages and the integration of objects and facilities for processing data protocols and standards.

2. Communicating with the CPU A computer system is made up of hardware and software. HARDWARE The mechanical or electrical parts of a computer system SOFTWARE Programs or code which controls the hardware in a computer system

3. What is the CPU? The CPU consists of: 1ALU – Arithmetic / Logic Unit 2CONTROL UNIT CPU stands for ‘ Central Processing Unit’ It is also known as the ‘ microprocessor ’ or ‘ processor ’. WELL KNOWN PROCESSORS: INTEL, AMD, (Cyrix)

4. How does the CPU communicate with the rest of the computer? The CPU communicates via BUS. There are two types of bus: 1 INTERNAL bus. 2 EXTERNAL bus. There are three types of internal bus: 1 Address bus. 2 Data bus. 3 Control bus. External bus means ‘ wires ’.

5. How does the CPU communicate with the rest of the computer? The bus transfers data to and from the CPU as electrical pulses – on or off – also known as binary code. 1010001 00011110 0101010 11111111 00000001 00000111 1111111 Devices cannot communicate directly with the CPU via bus. Each has its own INTERFACE UNIT to decode signals.

6. Parallel and Serial Bus Communication SERIAL BUS Serial bus transfers one bit (one eighth of a byte ) at a time. A common serial interface is the RS232C. Commonly used for external modems – 25-pin interface Commonly used for a mouse – 9-pin interface PARALLEL BUS Parallel bus transfers one byte at a time. Therefore is much faster than the serial bus interface. Parallel can only operate at short range – 2 or 3 metres.

7. How does software fit into all this? The diagram above shows that software (operating system) is controlling how the user interacts with the computer system: hiding the complexity of hardware. The average user is unaware of the huge number of tasks being performed by the OS behind the scenes. Software controls all data movements and every hardware action. So much is going on in fact that a user would not have time to do anything they wanted, so the operating system shields the user by creating a “ virtual machine ”.

8. Interfacing For peripheral equipment (such as printers) to work with a computer system, special software has to be installed on that system known as DRIVER SOFTWARE. This driver software works with the system hardware, other system software and the applications software wishing to use the peripheral, to allow it to work (i.e. print). Explain how you install hardware devices / peripherals, such as a printer onto a computer system. What part do BUFFERING and SPOOLING play in the printing process? Explain how they are elements of interfacing. USE CHAPTER 28 IN HEATHCOTE TO HELP YOU