|
⇤ ← Revision 1 as of 2004-03-17 20:01:28
Size: 1360
Comment:
|
Size: 1459
Comment:
|
| Deletions are marked like this. | Additions are marked like this. |
| Line 10: | Line 10: |
| * Remainder Section | * Remainder Section (Essentially the "other" section in that it has no impact on the entry into the critical section) |
| Line 14: | Line 14: |
| 1. '''Mutual Exclusion''': If process Pi is executing in the creical section, then no ohter processes can be executing in their critical sections. 1. '''Probress''': If no process Pi is executing in it's critical section and some processes whish to enter teir critical sections, then only those processes that are not executing in their remainder section can participate in the decision on which will enter its cretical section next, and this selection cannot be postponed indefinitely. 1. '''Bounded Waiting''': There exists a bound on the number of times that other precesses are allowed to enter their critical sections after a process has made a request to enter its critical section and before that request is granted. |
1. '''Mutual Exclusion''': If process Pi is executing in the critical section, then no other processes can be executing in their critical sections. 1. '''Progress''': If no process Pi is executing in it's critical section and some processes wish to enter their critical sections, then only those processes that are not executing in their remainder section can participate in the decision on which will enter its critical section next, and this selection cannot be postponed indefinitely. 1. '''Bounded Waiting''': There exists a bound on the number of times that other processes are allowed to enter their critical sections after a process has made a request to enter its critical section and before that request is granted. |
Back to ComputerTerms
A critical section contains the execution of code that must be executed exlusive of other processes. This is to avoid a RaceCondition.
Each process goes through the following:
- Entry Section: request to enter the critical section
- Critical Section
- Exit Section (Optional)
- Remainder Section (Essentially the "other" section in that it has no impact on the entry into the critical section)
KEY: A solution to the critical-section problem must satisfy the following three requirements:
Mutual Exclusion: If process Pi is executing in the critical section, then no other processes can be executing in their critical sections.
Progress: If no process Pi is executing in it's critical section and some processes wish to enter their critical sections, then only those processes that are not executing in their remainder section can participate in the decision on which will enter its critical section next, and this selection cannot be postponed indefinitely.
Bounded Waiting: There exists a bound on the number of times that other processes are allowed to enter their critical sections after a process has made a request to enter its critical section and before that request is granted.
We assume that each process is executing at a non-zero speed, but we make no assumption concerning the relative speed of the n processes
Back to ComputerTerms