MULTI USER OPERATING SYSTEMS
Introduction2
Multitasking2
Types of Multi User System3
CPU Architecture4
Memory4
Data Storage Devices5
Input / Output Devices5
Software Components5
Bibliography7
Introduction
Operating systems are the very basis of computer software programs. They exist in order for users to interact with the computer's hardware. An example would be MS- DOS. DOS however is a single user operating system which can only support input from one user at a time. So if more than one person needs to use a computer's resources, a different operating system is needed. Hence multi user operating systems.
These are operating systems which allow many users to share the resources of a processor at the same, for example UNIX, LINUX, or CICS.
They differ from network operating systems in that the latter are actually single user operating systems with, in the overall plan of the operating system, the only user being the system administrator and all other logins just being a program run by the administrator.
Since multi user systems share resources, such as the CPU, memory, storage and input/ output devices, as well as software applications and files, the operating system has to organise and control the access to these resources (called scheduling), the most common way of doing this being the Round Robin strategy where each process has a short but equal time slice. For this reason, multi user operating systems require a great deal of memory in order to work effectively.
Multitasking
A main feature of multi user systems is multi tasking. This is where the operating system provides the ability to run two or more programs at once. For example a user could be printing and typing at the same time. In actual fact, although the system appears to be running the tasks together the processor is rapidly switching...