Operating Systems (Cambridge (CIE) A Level Computer Science): Flashcards
Exam code: 9618
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Define operating system.
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Cards in this collection (52)
Define operating system.
An operating system is software that provides an interface between the user and the hardware in a computer system.
What does an operating system hide from the user?
An operating system hides the complexities of the hardware from the user, so a user does not need to know where on secondary storage data is kept.
Define user interface.
A user interface is how the user interacts with the operating system.
Name the four types of user interface.
The four types of user interface are command line interface (CLI), graphical user interface (GUI), menu and natural language interface (NLI).
How does a user interact with a command line interface (CLI)?
A user interacts with a command line interface using text-based commands.
What does WIMP stand for in a graphical user interface?
WIMP stands for windows, icons, menus and pointers.
True or False?
A menu interface presents the user with several options at each stage.
False.
A menu interface presents successive menus to the user with a single option at each stage.
A natural language interface uses the word to respond to spoken or textual inputs from a user.
A natural language interface uses the spoken word to respond to spoken or textual inputs from a user.
Give two examples of a device that uses a menu interface.
Chip and pin machines, vending machines and entertainment streaming services all use a menu interface.
Name the five key management tasks of an operating system.
The five key management tasks are memory management, file management, security management, hardware management and process management.
Define memory management.
Memory management is the operating system allocating main memory (RAM) between different programs that are open at the same time.
Which operating system management task makes multitasking possible?
Memory management makes multitasking possible, because it prevents data from different programs overwriting each other in RAM.
Define file management.
File management is the operating system creating, organising, manipulating and accessing files and folders on a computer system.
What do permissions allow the operating system to control?
Permissions allow the operating system to control who can access, modify and delete files and folders.
Security management includes password-protected system accounts, a firewall, virus scanning and file .
Security management includes password-protected system accounts, a firewall, virus scanning and file encryption.
Define device driver.
A device driver is a piece of software used to control a piece of hardware.
True or False?
The same device driver will work on any operating system.
False.
Device drivers are operating system specific and are regularly updated.
What is plug-and-play (PnP)?
Plug-and-play is the operating system automatically detecting and configuring new peripherals without manually installing device drivers or power cycling the system.
Define time slicing.
Time slicing is the operating system dividing processor time into small chunks and allocating them to different processes.
What does an operating system use to decide which process is executed next?
An operating system uses a scheduling algorithm to prioritise processes and decide which is executed next.
Define utility software.
Utility software is a collection of tools designed to help maintain a computer system.
Name four examples of utility software.
Examples of utility software include a disk formatter, a virus checker, defragmentation software, disk contents analysis / disk repair software, file compression and back-up software.
True or False?
Utility software is designed to perform a wide range of tasks.
False.
Utility software is designed to perform a limited number of tasks.
What does utility software interact with directly?
Utility software interacts with the computer's hardware, for example secondary storage devices.
What does a disk formatter do?
A disk formatter prepares a storage device for use by creating a file system and organising the space into sectors and tracks.
Give one reason a disk would need to be formatted.
A disk is formatted to wipe and re-initialise it, to change the file system format or to remove all data and errors before installing a new operating system.
What does a virus checker scan?
A virus checker scans email attachments, websites and downloaded files to search for issues.
Name the two ways a virus checker can identify malware.
A virus checker can use a list of known unique malware fingerprints (signatures), or monitor the behaviour of programs to identify suspicious activity.
Virus checkers check for updates so that the database of stays up to date.
Virus checkers check for updates so that the database of signatures stays up to date.
Define defragmentation software.
Defragmentation software groups fragmented files back together in order to improve the access speed of a hard disk drive.
Why does data on a hard disk drive become fragmented?
As files are deleted they leave gaps, and as new programs and data are added these gaps get filled, so data becomes fragmented.
True or False?
Defragmentation software can be used on any type of secondary storage.
False.
Defragmentation can only be used on magnetic storage.
What does disk contents analysis / disk repair software check?
It checks the structure and health of a disk, including files, folders, sectors and the file allocation table.
Give one task that disk repair software performs.
Disk repair software diagnoses and fixes errors such as bad sectors and file system corruption, and can recover lost or damaged files.
Define file compression.
File compression reduces the amount of secondary storage required by performing an algorithm on the original data.
What is the difference between lossy and lossless compression?
Lossy compression removes data, so the original file cannot be re-created. Lossless compression orders data more efficiently, so the original file can be re-created.
Why is back-up software used?
Back-up software creates copies of personal data to keep it safe in the event of accidental loss or data theft.
What is the difference between a full backup and an incremental backup?
A full backup copies all files, which is safest but slow. An incremental backup copies only files added or modified since the last backup, which is faster but less secure.
Backups can be scheduled to run at less busy periods of the day so they do not take up valuable resources.
Backups can be scheduled to run at less busy periods of the day so they do not take up valuable system resources.
Define program library.
A program library is a collection of pre-written code, called library routines, that programmers can reuse in their own software.
Name two common tasks that library routines can perform.
Library routines can perform common tasks such as sorting, displaying graphics, playing sounds and managing data.
How does using a program library save development time?
Pre-written routines can be reused, so programmers do not need to write common functions from scratch.
Why does using a program library improve reliability?
Library routines are usually thoroughly tested and debugged, which reduces the chance of errors.
How does a program library promote standardisation?
A program library promotes consistency in how common tasks are implemented, such as file handling and sorting.
True or False?
Using a program library increases the duplication of code across programs.
False.
A program library promotes code reuse, because well-tested routines can be used in multiple programs, reducing duplication.
Define dynamic link library (DLL).
A dynamic link library is a file containing pre-written code, such as functions or routines, that can be used by multiple programs at runtime.
When is a DLL loaded into memory?
A DLL is only loaded when it is needed at runtime, which saves system resources.
How does using a DLL reduce program size?
A DLL keeps reusable code separate from the program, so the program itself is smaller.
Why does using a DLL make maintenance easier?
A DLL only needs to be updated once, and every program that uses it benefits from the update.
DLLs save memory because they can be between programs.
DLLs save memory because they can be shared between programs.
Give one disadvantage of using a DLL.
A program may fail to run if a required DLL is missing, newer DLLs can cause version conflicts, altered DLLs can pose security risks, and errors inside a DLL can be hard to trace across multiple programs.
True or False?
Updating a DLL can stop a program that uses it from working.
True.
Newer DLLs that are not compatible can cause version conflicts.
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