3.3.1 The function & Purpose of Operating Systems

[3.3.1 THE FUNCTION OF OPERATING SYSTEMS]

The operating system is responsible for controlling the hardware and interacting with it. It also provides an interface for the user and for the use of applications.

Things that the Operating system handles:

v  The processer, it decides what instructions to execute and handles the interrupt sequence.

v  The memory, primary and secondary memory. It manages memory by allocating it and cleaning it etc.

v  All external devices via device drivers to allow communication between the devices and the user.

v  Utility programs e.g. system cleanup, de-frag and file handlers.

v  Networking, providing communication between other machines and devices over a network using protocols.

v  Security, the allowing and denying requests to access other resources.

v  The User interface, users interact with applications and programs through the interface, mainly graphical user interfaces but can also be command line for admin work.

[INTERRUPT HANDLING ROUTINES]

Interrupt: Signal from a device or source seeking attention of the processor

The fetch decode execute cycle is constant and goes like this;

Ä  Checks for an instruction

Ä  Fetches that instruction

Ä  Decodes that instruction

Ä  Executes that instruction

Ä  Checks for any interrupts

Ä  Transfers…