Group 6 Comp 129 Chapter 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

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

Windows XPMAC OSX Can only see one screen at a timeEnables screen sharing able to run disk operating systemsAble 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

 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.

 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.

 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.

 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.

 This function allows the user to communicate with other computer users.  This involves even graphics, written communication, and programs communicating to each other.

 GUI (Graphic User Interface)  Multi-user OS  Multiprocessing OS  Multitasking OS  Multithreading OS

 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

 The multi-user operating system allows multiple people to use the same computer at the same or different times  Examples: ◦ Linux ◦ Unix ◦ Windows 2000

 The multiprocessing operating systems are capable of using and supporting more than one computer processor.  Examples ◦ Linux ◦ Unix ◦ Windows 2000

 This system can allow multiple software processes to run at one time.  Examples: ◦ Unix ◦ Windows 2000

 A multithreading operating system allows different parts of the software program to run at the same time.  Examples: ◦ Linux ◦ Unix ◦ Windows 2000

 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.