Computer Systems

Question	Answer
Computer System	A combination of hardware and software components that allow input, processing and output of data.
Hardware	The physical components that make up a computer system.
Software	The programs that run on a computer system.
Input Devices	Hardware that accepts data into the computer. They take real world analogue data and convert it into a digital form that can be stored on a computer.
Output Device	Hardware that presents the results of processing to the user or actuators that perform a task automatically. They use digital data from a computer and produce it in a form that is understandable or usable.
Storage Device	Hardware that is used to store fi les long term and is non-volatile, such as hard disks,
Reliability	How far you can depend on the computer system being available when you need it. Usually measured in terms of availability.
Availability	The proportion of time that a system is operational, usually expressed as a percentage over a period of time. E.g. 95% measured over one year.
MTBF	Mean Time Between Failure: a measure of availability often quoted by hardware manufacturers.
Redundancy	Spare hardware components are built into a system so that, in the event of a component failing, the system can swap over to the spare one.
Disaster Recovery	Where a company has plans to replace a system quickly if there is a catastrophe (fi re, fl ood, bomb etc). Designed to minimise the time the system is down.
Ethics	Ensuring that computer systems are fair and morally correct

Resource summary

	Created by Dean Whittle over 9 years ago