4.1 Types of software and interupts

System software

Provides the services that the computer requires, including operating system and utility software, managing and maintaining the hardware and software. Includes utility software and operating system and firmware

Application software

Provides services the user requires allowing them to preform tasks. Includes Words processor, web browser, video editing software, spread sheet, games, email client, database etc.

Functions of an operating system

Manages files

Handles Interrupts

Provides an interface

Manages peripherals and drivers

Manages memory

Manages multi tasking

Provides a platform for running applications

Provides system security

Manages user accounts

How does an operating system allow for multi tasking

PCs often need to preform many complex tasks at a time the OS is needed to handle this multi tasking therefore it provides the user the ability to handle interrupts

How does an operating system manage files

Creates organises, manipulates and accesses files and folder on a computer system

How does an operating system handle interrupts

Interrupts require the immediate attention of the CPU and in order to maintain the smooth running of the system the interrupts need to be handled and processed in a timely manner. Operating system detects interrupt pauses current task and runs correct routine to deal with it.

How does an interface provide an user interface

Allows user to interact with the operating system

How do operating systems manage peripherals and drivers

Manages how hardware (peripherals) interact with software

How do software manage memory

Allocates main memory between different programs that are open at the same time and copies primary storage to secondary if needed.

This allows multitasking to happen

What is multi tasking

Process made possible by OS simultaneously managing system resources to give the user the perception of being able to use multiple programs at the same time, by quickly switching in between them.

Interrupt signal is used.

Providing system security explained

OS provide various security features such as password protected system accounts, firewall, virus scanning and file encryption. System account can also be restricted from doing certain things like Editing network settings, installing unapproved software or changing the account settings of other users.

User management

Operating system allows different users to log into a computer and maintain settings for individual users such as themes. System administrator allocated different access rights for different users on a network.

Firmware functions

Permanently store instructions in ROM

Stores instructions to boot/start up the computer

Provides operating system with platform to run on

Allows and manages communication with hardware

Stores instructions securely to stop them being corrupted

How hardware, firmware and OS are required to run application software

Application is run on operating system

Operating system run on firmware

Firmware run on hardware

What is an interrupt?

Signal for the CPU to stop what it is doing and do something else as a higher priority

How does firmware set up the OS when it is turned on

BIOS runs automatically and checks the hardware works

BIOS starts the bootloader which copies the OS from the hard drive to the RAM

OS starts running

This process is known as the bootstrap

Firmware example

BIOS

Why is an interrupt generated in the software??

Dividing by 0

Null value

2 processes trying to access the same memory location

Why is a interrupt generated in the hardware

Pressing a key on the keyboard

Moving the mouse

Plugging in device

How is an interrupt handled using a interrupt service routine

Interrupt made and given priority

Interrupt sent to CPU

Interrupt placed in a queue

CPU stops current task to check the queue using an interrupt service routine

If it is highest priority then interrupt is processed