CLI

GUI

resources are allocated to a process for a specific time limit

the process can be interrupted while it is running

the process is given a priority so it can have resources according to its priority (the risk here is that a low priority process could be starved of resources).

OS provides a platform for running applications. Applications loaded into RAM and hosted on OS. Different parts of OS loaded into and out of RAM as Program Runs.

customise their screen layout and other settings

use separate folders and files and to manage these themselves.

file naming conventions which can be used

performing specific tasks (for example, create, open, close, delete, rename, copy, and move)

maintaining the directory structures

ensuring access control mechanisms are maintained

ensuring memory allocation for a file by reading it from the HDD/SSD and loading it into memory.

communicates with all input and output devices using device drivers

uses a device driver to take data from a file (defined by the operating system) and translates it into a format that the input/output device can understand

ensures each hardware resource has a priority so that they can be used and released as required

manages input/output devices by controlling queues and buffers

manages the primary storage (RAM) and allows data to be moved between RAM and HDD/SSD during the execution of programs

keeps track of all the memory locations

carries out memory protection to ensure that two competing applications cannot use the same memory locations at the same time

a timing signal

an input/output process (for example, a disk drive or printer requiring more data)

a hardware fault (for example, a paper jam in the printer)

user interaction (for example, the user presses a key (or keys) on a keyboard, such as <CTRL><ALT><BREAK>, which causes the system to be interrupted)

software errors that cause a problem (for example, an .exe file that cannot be found to initiate the execution of a program, two processes trying to access the same memory location, or an attempt to divide by zero).

by carrying out operating system updates as and when they become available

ensuring that anti virus software (and other security software) is always up to date, preserving the integrity, security and privacy of data

by communicating with, for example, a firewall to check all traffic to and from the computer

by making use of privileges to prevent users entering ‘private areas’ on a computer that permits multi-user activity (this is done by setting up user accounts and making use of passwords and user IDs); this helps to ensure the privacy of data

by maintaining access rights for all users

by offering the ability for the recovery of data (and system restore) when it has been lost or corrupted

by helping to prevent illegal intrusion into the computer system (also ensuring the privacy of data).