Chapter 1 Flashcards
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 Device
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. For example: keyboard, mouse, microphone, webcam, scanner, sensors.
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. For example: monitors, printers,speakers, projectors, actuators (motors).
Storage Device
Hardware that is used to store files long term and is non-volatile, such as harddisks, memory sticks, magnetic tapes and CDs.
System Reliability
How far you can depend on the computer system being available when you needit. Usually measured in terms of availability.
System 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.
Mean Time Before Failure (MTBF)
Mean Time Between Failure: a measure of availability often quoted by hardware manufacturers. For example 2.56 years between failures means that, on average, the hardware can be expected to last 2.56 years before it goes wrong.
System 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.
System Disaster Recovery
Where a company has plans to replace a system quickly if there is a catastrophe (fire, flood, bomb etc). Designed to minimise the time the system is down.
