Computer Systems

Define Hardware

Hardware is the electrical and mechanical aspects of a computer system.

Define Software

The programs that allow a computer to function

What are the 2 Main Types of software?

Application and System software

What are the 4 Types of Application Software?

• General Purpose

• Special Purpose Software

• Bespoke

• Off-the-shelf

What Are the 4 types of system software?

• Operating Systems

• Utility Programs

• Translators

• Library Programs

What is the Purpose of System Software?

Software that provides a means for other software to run

Name 5 things that System Software controls.

• Peripheral Management

• Translating Program code into machine code

• Allocating Jobs to the Processor

• Downloading Software

• Checking for Viruses and maintaining security

Define Operating System

A program or collection of programs that controls the entire operations of a computer

What are 6 tasks of the operating System?

• Backing Store Management

• User Interface

• Memory Management

• Peripheral Magement

• User Management

• File Management

What does Utility Software do?

Utility Software is used to maintain and optimise the Computer

What are 6 things that Utility Software does?

• Defragmentation

• Install / Uninstall Software

• Keep Software Up-to-Date

• Monitor Resources

• Virus checking

• Compression

• Backups

What is a library?

A collection of pre-compiled subroutines that can be used by other programs

What is the role of a translator?

Used to translate high level or assembly code into machine code.

What are the 3 types of translator?

• Assemblers

• Compilers

• Interpreters

What is the role of an assembler?

To translate assembly code into machine code

What is the role of an interpreter?

To translate high level program code into machine code one line at a time.

What is the role of a compiler?

To translate high level program code into an executable object code file. This file can be run in future without a compiler.

Define object code

Machine code

Define General purpose software

Software that can be used to preform a range of generic tasks

Define Special Purpose Software

Software that is used to preform one specific task

Define Off-The-Shelf software

Software that has already been made

Define Bespoke Software

Software that is made for you own exact specifications

What are the pro’s of off-the-shelf software?

• Cheap

• Well tested

• Can be used immediately

What are the con’s of off-the-shelf software?

• May not do exactly what you want

• you have little control over its features

What is the role of an API?

An API is an interface that allow the user to issue complex commands easily, without having to know what is being carried out. E.g. Clicking on a website link to open a website

Define Multitasking

Changing the task the processor is doing quickly so that it seems that they are being completed simultaneously

What is the Scheduler?

The scheduler is a module of the OS that is responsible for ensuring the processor is running efficiently by ordering tasks correctly

What is the ‘round robin’ scheduling program?

each process is given a time slice to execute instructions

What are 3 things that the I/O manager does?

• Communicates with the I/O devices via the CPU’s I/O controller

• Ensure that I/O devices are on and able to receive data.

• Deals with interrupts

Give an example of an interrupt

(an ‘out of paper’ message from a printer)