OPERATING SYSTEMS

Group 6Comp 129Chapter 4

An operating system s a set of programs made to manage the resources of a computer.

The OS performs five basic functions:◦ Starts the computer◦ Manages applications◦ Manages memory◦ Handles messages from input and output devices◦ Provides a means of communicating with the user

The basics about operating systems

Linux Windows XP Unix Windows 2000 Mac OS 8-10 Mac OS X BSD

Examples of Operating Systems

Windows XP MAC OSX

Can only see one screen at a time Enables screen sharing

able to run disk operating systems

Able to run DOS

User interface adds clutter and takes up space

High-tech interface

Virus issues- too many viruses, works, malware

Extremely secure-to new to have many viruses.

64-bit 64-bit

Windows XP v. MAC OSX

When your operating system starts the computer, the OS gets loaded into the RAM.

The process of load the OS s called booting. The central part of the operating system,

called the kernel gets copied from hard disk into memory during booting.

The smaller parts of the OS are kept on hard disk unless needed. These parts are called nonresident.

Function #1 Starting the computer

This is the most important function of an operating system when it comes to the quality of your OS.

Nowadays, operating systems can load and run more than on application at one time, making it much more convenient for users.

Operating systems are able to run more than one application at a time because it constantly switches between whichever application is being used. The other application s known as inactive.

Function #2 Manages Applications

Memory is used so the OS does not need to go back to the hard disk to get instructions every time you use a program.

The job of the OS is to keep each program’s instructions in it’s own piece of memory so it does not get mixed up with another program.

The more RAM you have, the more real memory the operating system can use for your programs.

Function #3 Managing Memory

Operating systems come with drivers for input and output devices. These drivers allow communication between the OS and the device.

For devices that aren’t already set up with the operating system, they can usually detect and automatically install the drivers needed.

The devices send interrupts, or notices to the OS that something has been connected or changed.

Function #4 Handling Input and Output

This function allows the user to communicate with other computer users.

This involves even graphics, written communication, and programs communicating to each other.

Function #5 Providing the User Interface

GUI (Graphic User Interface)

Multi-user OS

Multiprocessing OS

Multitasking OS

Multithreading OS

Types of Operating Systems

The Graphics User Interface Operating System includes graphics and icons that are usually maneuvered by the mouse.

Examples:◦ System 7.x◦ Windows 98◦ Windows CE

GUI

The multi-user operating system allows multiple people to use the same computer at the same or different times

Examples:◦ Linux◦ Unix◦ Windows 2000

Multi-user Operating System

The multiprocessing operating systems are capable of using and supporting more than one computer processor.

Examples◦ Linux◦ Unix◦ Windows 2000

Multiprocessing OS

This system can allow multiple software processes to run at one time.

Examples:◦ Unix◦ Windows 2000

Multitasking Operating System

A multithreading operating system allows different parts of the software program to run at the same time.

Examples:◦ Linux◦ Unix◦ Windows 2000

Multithreading OS

The operating system will be able to start up the computer and programs in less time.

Systems will begin to come with more memory so users do not have to purchase separate memory.

Drivers will continue to advance. There will become more new drivers that can be downloaded from the internet.

Computers will allow more than one user to use the same system at the same time.

Future Improvements