Component 15 - Key Definitions

Question 1

Input and output

Answer 1

Input = data going IN to a computer system or program Output = data coming OUT of a computer system of program

Question 2

Pre-Conditions

Answer 2

Criteria which must be met before something can happen. In terms of thinking ahead, pre-conditions are the things you must consider before designing a program or block of code – what inputs do you need, what data do you need from external sources, what actions must/will the user perform etc.

Question 3

Caching

Answer 3

Caching (not in the CPU sense of the word Cache) is when small amounts of data are kept in memory or in a buffer so that they are available to a program without delay. Caching data not only speeds up program execution but can also be used to smooth out variability in things like network connections (caching a video before playing it, for example, would hide any dips in network performance as there would be enough data cached to continue playback without interruption whilst the network performance increases again)

Question 4

Reusable program components

Answer 4

These are functions, procedures, classes, libraries or DLL’s. These are blocks of pre-written, pre-tested code which we can use in our programs to reduce the time taken to develop software. It has the distinct advantage that the code should be robust and reliable

Question 5

sub- procedures/functions

Answer 5

Sub procedures and functions are used to break up complex problems into smaller component parts. Each function or procedure will perform a specific task and have a set of inputs and expected outputs. By using these components it makes programs easier to design, reduces repetition, increases the reliability and robustness of code and enables us to delegate parts of programs to different developers who can work on their own blocks of code independently.