Computer-science_A-level_Cie
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computers-and-components6 主题
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logic-gates-and-logic-circuits2 主题
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central-processing-unit-cpu-architecture6 主题
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assembly-language-4 主题
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bit-manipulation1 主题
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operating-systems3 主题
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language-translators2 主题
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data-security3 主题
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data-integrity1 主题
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ethics-and-ownership3 主题
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database-concepts3 主题
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database-management-systems-dbms-1 主题
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data-definition-language-ddl-and-data-manipulation-language-dml1 主题
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computational-thinking-skills1 主题
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algorithms14 主题
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data-types-and-records2 主题
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arrays2 主题
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files1 主题
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introduction-to-abstract-data-types-adt1 主题
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programming-basics1 主题
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constructs2 主题
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structured-programming1 主题
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program-development-life-cycle2 主题
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program-design-2 主题
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program-testing-and-maintenance3 主题
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user-defined-data-types1 主题
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file-organisation-and-access-3 主题
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floating-point-numbers-representation-and-manipulation3 主题
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protocols2 主题
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circuit-switching-packet-switching1 主题
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processors-parallel-processing-and-virtual-machines5 主题
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boolean-algebra-and-logic-circuits4 主题
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purposes-of-an-operating-system-os3 主题
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translation-software3 主题
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encryption-encryption-protocols-and-digital-certificates3 主题
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artificial-intelligence-ai4 主题
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recursion1 主题
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programming-paradigms4 主题
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object-oriented-programming7 主题
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file-processing-and-exception-handling2 主题
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data-representation5 主题
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multimedia3 主题
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compression2 主题
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networks-and-the-internet11 主题
utility-software
Utility software
What is utility software?
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Utility software is a collection of tools designed to help maintain a computer system
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Utility software is designed to perform a limited number of tasks
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Utility software interacts with the computers hardware, for example, secondary storage devices
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Some utility software comes installed with the operating system
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Examples of utility software include:
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Disk formatter
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Virus checker
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Defragmentation software
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Disk contents analysis/disk repair software
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File compression
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Back-up software
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Disk formatter
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A disk formatter prepares a storage device (like a hard drive or USB stick) for use by creating a file system and organising the space into sectors and tracks
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It is needed:
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To wipe and re-initialise a disk before use
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To change the file system format (e.g. FAT32, NTFS)
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To remove all data and errors before installing a new OS or reusing the drive
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For example:
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Formatting a new external drive before saving files
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Reformatting a corrupted USB stick to make it usable again
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Virus checker
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Virus checking software is a combination of different software to prevent computers from being susceptible to viruses and other malicious software
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It typically includes:
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Anti-virus
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Anti-spam
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Anti-spyware
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A virus checker scans through email attachments, websites and downloaded files to search for issues
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Two ways virus checkers can approach the task are:
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Use a list of known unique malware fingerprints (signatures) to block immediately if they try to access your device in any way
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Monitor the behaviour of programs to identify suspicious activities that might indicate malware such as;
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Rapid deletion/modification of files
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Attempts to access sensitive data/resources
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Communicating with known malicious servers
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Virus checkers will also perform checks for updates to ensure the database of signatures is up to date
Defragmentation software
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Defragmentation software groups fragmented files back together in order to improve the access speed of a hard disk drive (HDD)
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As programs and data are added to a new hard disk drive, it is added in order, over time as files are deleted this leaves gaps
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As programs and data are added over time, these gaps get filled and data becomes fragmented
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Defragmentation can only be used on magnetic storage

Disk contents analysis/disk repair software
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This utility checks the structure and health of a disk, including files, folders, sectors, and the file allocation table
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It is needed:
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To diagnose and fix errors on the disk (e.g. bad sectors, file system corruption)
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To recover lost or damaged files
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To improve system performance by identifying and repairing issues
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For example:
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Running Check Disk (chkdsk) on Windows to repair file system errors
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Using a disk utility on macOS to verify and repair drive problems
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File compression
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Compression reduces the amount of secondary storage required by performing an algorithm on the original data
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Lossy compression physically removes data from the original data to reduce its size, the original file can not be re-created
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Lossless compression uses mathematics to order data more efficiently reducing its size, the original files can be re-created as no data is lost
Back-up software
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Back-up software is used to create copies of personal data in order to keep it safe in the event of:
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Accidental loss
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Data theft
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Backups can be automated and scheduled to happen at less busy periods of the day, to not take up valuable system resources (e.g. overnight etc.)
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Backups can be made in two ways:
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Full – all files are backed up (saftest, slow)
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Incremental – only files that have been added/modified since the last backup are backed up (faster, less secure)
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Backups can be stored locally (secondary storage) or remotely (cloud)
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Backup software can be purchased or come as a standalone application bundled with an operating system
Worked Example
Draw one line from each utility software to its correct description.
Utility software Description

[4]
Answer

Responses