Candidates should be able to:  describe the purpose and use of common utility programs for:  computer security (antivirus, spyware protection and firewalls)  disk organisation (formatting, file transfer, and defragmentation)  system maintenance (system information and diagnosis, system cleanup tools, automatic updating) Slide 1 GCSE Computing Software 2

 Virus:  A computer program that attaches to existing files and can replicate itself and spread from one computer to another, often with user help.  A virus almost always corrupts or modifies files on a targeted computer.  Worm:  A self-replicating computer program which uses a computer network to send copies of itself to other computers on the network without any user intervention.  Unlike a computer virus, a worm does not need to attach itself to an existing program.  Worms almost always cause some harm to a network, even if only by consuming bandwidth.  Trojan:  A destructive program that pretends to be a harmless application.  Unlike viruses and worms, Trojans do not replicate themselves, but they can cause just as much harm. Slide 2 Computer security – malware types

 Spyware:  Software installed on a computers that collects information about users without their knowledge.  Spyware is secretly installed and its presence is typically hidden from the user and difficult to detect.  Many spyware programs are designed to capture usernames and passwords, for use in identity theft or fraud.  Unlike a virus or a worm, spyware does not usually self-replicate. Slide 3 Computer security – malware types

 This is software that is used to prevent, detect and remove malware:  It prevents the installation of malware onto the computer.  It protects the computer by preventing installed viruses from altering important files such as the boot sector or the operating system.  It detects installed malware by periodically scanning the computer.  It then deletes or quarantines any malware that it finds.  To be effective, the virus definitions file that the antivirus software uses to check for malware must be kept up-to- date. Slide 4 Computer security – antivirus software

 This is software or hardware that permits or denies network transmissions between networks based upon a set of rules.  It is often used to protect networks from external hacking attempts while allowing legitimate communications to pass. Slide 5 Computer security – firewall

 Formatting prepares a hard disk, floppy disk or flash memory for data storage.  The formatting process may:  create the file system (high level formatting)  delete any existing data and check and fix any errors in the storage media (low-level formatting).  Formatting deletes all the data stored on the storage media.  A low level format of a hard disk organises the surface into tracks and sectors.  The tracks form concentric circles that radiate outwards from the spindle in the centre to the edge of the disk.  A sector is a subdivision of a track that can hold a fixed amount of data. Slide 6 Disk organisation - formatting

 File transfer is a generic term for the act of transmitting files over a LAN or a WAN such as the Internet.  There are numerous ways and protocols to transfer files over a network.  Computers which provide a file transfer service are often called file servers.  Depending on the perspective, the file transfer is either called uploading or downloading. Slide 7 Disk organisation - file transfer

 Disk fragmentation occurs when the operating system:  splits up large files when saving them.  tries to fill the gaps created when other files are deleted or their size changes.  Defragmentation is carried out by software that reorganises files or parts of files so that the data is physically stored together  This has two benefits:  It speeds up file access.  It ensures that free disk space is maximised by collecting it together.  A simplified animation showing defragmentation. Slide 8 Disk organisation - defragmentation

System maintenance  System information and diagnosis  software that provides information on the hardware and software of a computer system and offers a diagnosis of any problems that are found.  System cleanup tools  software that searches the computer system for settings that are wrong and files which are no longer needed.  setting errors are corrected or deleted  files that are no longer needed are deleted to free up disk space and improve performance.  Automatic updating  software that searches the Internet for updated versions of the software on the computer and downloads and installs the updates so that the computer system always has the latest version, including fixes for known problems/security issues.  Backup software  software that assists in backing up selected files or even the entire computer hard drive.