Software

Introduction n A computer can’t do anything without a program of instructions. n A program is a set of instructions a computer carries out. n An algorithm is a sequence of steps or calculations. n Machine code is the basic instructions built into the processor. n A computer language is the set of words and symbols used in writing a program. n A program is translated into machine code before it can be run.

Introduction - cont. Programs can be translated by: n a compiler, which translates a program into machine code, OR n an interpreter which interprets one line at a time as the program is being run.

Software Software is a general term for programs which are written to help computer users. A computer system requires two types of software: n systems programs which make the computer work efficiently; n applications programs which help users to solve problems. n A utility program is a systems program that performs one task.

Operating systems An operating system is systems software which controls the general operation of a computer. The functions of the operating system include: n allowing users to run programs and organise files; n dealing with errors; n maintaining security. n making the best use of the store and peripherals ;

Application programs An application program can be: n custom designed - designed to solve a particular problem for a particular person or organisation; n application specific - designed for a particular type of application; n general purpose - for use in a wide variety of applications.

Data transfer Data can be moved from one packet to another: n by being exported as a file from one and imported into the other; n by being cut or copied from one and pasted into the other.

What software To decide which package to use you have to decide n what form the input data will take; n what processing operations are required; n what output is required.