4.1 types of software and interrupts

• General features of system software (3)

  1. Controls and manages the operation of hardware

  2. Provides a platform on which other software can run

  3. Provides a human computer interface
• Features of application software (2)

  1. Perform various applications and software as user requires

  2. May a suite of programs
• 3 typical application software

  1. Word processor

  2. Spreadsheet

  3. Database
• What are word processor used for

  Used to manipulate a text document with provided tools
• Functions of word processor (3)

  1. Copy and paste functions

  2. Spell checkers and thesaurus

  3. Importing photos
• What are spreadsheets used for


  Organise and manipulate numerical data in a grid made of cells which are identified using unique combinations of columns and rows
• Functions of a spreadsheet (3)

  1. Formulas for carrying out calculations

  2. Produce graphs

  3. Modelling
• What is a database used for

  To organise, manipulate and analyse data into rows called records and columns called fields which provides the basic structure for organisation
• Functions of databases


  1. Carry out queries on data base

  2. Produce a report
• Typical software system (5)


  1. Compiler

  2. Linkers

  3. Device drivers

  4. Utilities

  5. Operating system
• What are compilers used for

  Translate high level languages (source code) into machine code (object code) which can be used again to perform the same task
• What are linkers used for


  Takes objects and combines them into a single program which simplifies the programming task since the program can then be broken up into smaller sub-tasks
• What are device drivers used for

  Enables hardware devices to communicate with the computers operating system and translates data into a format understood by a hardware peripherals
• What are USB device drivers


  They contain the vendor id, product id and unique serial numbers about the device called descriptors which allows the USB bus to ask a newly connected device what it is
• What happens when a device has no serial number

  The operating system will treat it as new device when plugged in
• What are utilities used for

  Help manage, maintain, and control computer resources
• Examples of utilities (6)

  1. Anti-virus & spyware

  2. Back-up of files

  3. Disk repair

  4. Secuirity

  5. Screen savers

  6. Device driver
• What do Virus checkers do

  Protect devices from malware
• What are two conditions with virus checkers

  Operating system must be kept thoroughly up to date and should run in the background
• Common features of virus checkers (3)

  1. Check software before they are run

  2. Compares a possible virus against a database of known viruses

  3. Put any possible infected files into quarantine
• What will reduce HDD head movements

  If files are stored in contiguous sectors
• What does a disk defragmenter do

  Rearrange the blocks of data to store files in contiguous sectors
• How do disks become fragmented

  Files are added or deleted, and the operating disk has to store file blocks wherever space is available. This slows down performance
• What does backup software do (2)

  1. Allow a schedule for backing up files to be made

  2. Only carry out a back-up procedure if there have been any changes made to a file
• What three versions of a file should there be for total security (3)

  1. Current version stored in secondary storage device

  2. A locally backed up version

  3. A remote-back up version stored away from the computer
• What does the Microsoft Window environment offer using the back-up utility (3)

  1. Restore data from the back-up

  2. Create a restore point which is a 'time machine'

  3. Option of where to save back-up files
• How does Windows use File History

  Take snapshots of files and stores them on external HDD and builds up a vast library backing up every hour
• How does the MAC OS offer Time machine

  It erases the contents of a selected drive and replaces them with the contents from the back-up with a HDD and SSD
• What does the Time machine automatically do (3)

  1. Back-up every hour

  2. Daily back-ups for the past month

  3. Weekly back-ups for all the previous months
• What is Security software and what does it do (3)

  1. Manages access control and user accounts

  2. Uses encryption and decryption

  3. Oversees the updating of software
• What are Screensavers


  Programs that supply moving and still images on the monitor screen after a period of inactivity and the computer will automatically log out
• What was screensavers originally used for

  Protect older CRT monitors which would suffer from 'phosphor burn
• What tasks do screensavers activate in idle state (2)

  1. Virus scans

  2. Distribute computing applications
• What are operating systems (4)


  1. They enable computer systems to function correctly

  2. Allow users to communicate with computer systems

  3. Provides both the environment in which applications run

  4. Disguises the complexity of computer software and hardware
• Examples of operating systems

  Apple Mac OS, Google Android and Apple IOS
• What are most operating systems stored

  HDD and SSD since they tend to be very large programs
• What does the computer interface form

  Command line interface and graphical user interface
• Difference between CLI and GUI

  Command Line Interface requires a user to type in instructions in order to choose options but Graphical User Interface allows the user to interact with a computer using pictures or symbols rather than having to type in commands
• What is WIMP


  Windows icons menu and pointing device which was developed for use of personal computers and a mouse is used to control a cursor and icons are selected to open/run windows
• What are post-WIMP


  Mobile phones and tablets use this with the use of touch screen with the fingers