Operating Systems - OCR Computer Science GCSE - Year 10

What are operating systems?

They provide the link between users, computers and peripherals.

What are some examples of operating systems?

Windows, macOS, iOS, Android

What are the different types of system software?

operating systems, utility programs, program translators

What are the two types of software?

system software and application software

What are some of the things that operating systems are responsible for managing?

user interface, memory management, multitasking, peripheral management and drivers, user management, file management

What is user interface?

a system that allows a computer and a user to interact and perform useful functions

What is are some examples of user interfaces?

GUI - Graphical User Interface, Menu-driven inetrface, CLI: Command Line Interface, Voice activated, Real-time

What does GUI stand for?

graphical user interfaces

What are some examples of desktop interfaces?

pointers, widnows, menus, icons, drag and drop

What are some examples of smartphone and touch interfaces?

no pointers in general as they cannot be seen under a finger, windows (for apps) generally take up the full screen

How do command line interfaces work?

Text commands are entered into the computer.

What are advantages of command line interfaces?

Requires very little processing, saves money as there is no need for an expensive graphics card, requires much less hard disk storage space, requires less RAM.

What are menu-driven interfaces used for?

Often used by devices that have a dedicated function. E.g. MP3 players, ATM machines, self service checkouts.

What is memory management?

To run a program, the computer must copy the program from storage into main memory. This is because data used by the program is copied into main memory. The operating system keeps a record of where each program and its data are located. The operating system will make sure not to overwrite existing programs and data.

What is multi-tasking?

Where an operatiing system manages many tasks happening at the same time. This may be having a web browser open whilst playing music and messaging friends. Many other background processes also are running. The operating system decides which process will next run on the CPU and for how long.

Describe how the operating system manages multitasking.

The operating system manages multitasking by using time slices and scheduling. It switches quickly between tasks so that multiple programs appear to run at once. It decides how long each task runs and in what order using scheduling algorithms.

Describe how the operating system manages memory.

The operating system allocates memory to programs when they are opened. It tracks which parts of memory are in use and protects each program's memory space. When programs are closed, the OS frees up the memory for other use.

What is systems software?

Software that governs the computer system.

What is an operating system?

A suite of programs that manages and controls a computer.

What is an applications software?

Allows a user to perform tasks.

What is meant by paging?

Paging is a method of memory management that breaks up memory into fixed-size blocks.

What is a device driver?

A device driver is a program that allows an operating system to control a peripheral.

What is the purpose of utility software?

Helps to maintain the system.

What is a backup?

A copy of data which is made in case of data loss.

What are the two types of backup?

The two types of backup are full and incremental.

What is fragmentation?

Fragmentation is where a file is stored non-contiguously on a disk.

What is defragmentation?

Defragmentation is where files are reordered to they are stored contiguously on a disc.

What are interrupts?

Signals sent to the CPU by external devices to indicate an event that needs immediate attention

What are the two types of interrupts?

Hardware interrupts and software interrupts.

What do interrupts do?

They tell the CPU to suspend its current activities and execute appropriate instructions.

Describe hardware interrupts.

Hardware interrupts are generated by hardware devices - for example, printer out of paper.

Describe software interrupts.

Software interrupts are generated by programs - for example, a divide-by-zero error will cause an error message to be displayed.

What is a peripheral?

An external device connected to a computer system to input or output data.

What is peripheral management?

How the operating system controls and communicates with external hardware devices connected to a computer

What are some examples of peripherals?

Mice, keyboard, printers, displays, digital cameras, graphic tablets.

How does sending data to a printer work?

The data will be sent to a print queue or buffer which is a special area of memory in a computer print server or the printer itself. Any data in the print queue is transmitted to the printer, typically a page at a time. The printer will send its status back to the operating system which reports any errors to the user. For example, the operating system may display an "out of paper" error message

What type of peripheral is the hard disk and what does it do?

Storage peripheral; manages where on the disk files are written, keeps track of where they are so they can be retrieved, makes sure no file overwrites another file

What is file management?

Allows the user to do various things with files.

What are some features of file management?

Naming files, allocating files to folders, moving files, saving files, copying files, deleting files.

What is user management?

Where the OS restricts user access to files based on who owns them.

What are access rights?

If a computer is used by more than one person, each user should be able to see only their own files. Users and system administrators have different levels of access rights. Some users may be allowed to read files but not edit them

What are some advantages and disadvantages of voice-driven interface?

Advantages: hands-free, speeds up processes. Disadvantages: commands may be misheard, limitations in what can be performed.

What are some advantages and disadvantages of menu-driven interfaces?

Advantages: user friendly, easy to use.

Disadvantages: annoying to find specific data.