الفهرس Only 14 pages are availabe for public view
 |  | from | 127 |  |  |
| | | from | 127 | | |
Abstract
The central themes of the operating systems are multiprogramming and distributed processing. The fundmenal tecnology of the operating system design is concurrency. When multiple processes are executing conflict ressolution and cooperation arise. The main problem associated with concurrency are mutual exclusion and deadlock.
mutual exclusion is a condition in which there is a set of concurrent process where only one process is able to access a given resource at any time. Mutual exclusion techniques can be used to resolve conflicts, such as competition. Mutual exclusion can be implemented in the Uniprocessor system as well as shared memory multiple processor systems using sotware algoeithms and operating system algorithms.
On the other hand, there are several algorithms have been proposed to enforce mutual exclusion in the distributed systems. These algorithmes can be claddified into to groups, according to their major design approch. These two groups are token-based algorithms and permission-based algorithms. According to the token-based approch, the right to enter the CS is given by the possession of a special object called ”token”. The singular existance of the token guarantees the requirement for mutual exclusion. The prossession of the token implies the right to enter the CS.