0
A bus based multiprocessor uses Snoopy cache to achieve coherent memory. will semaphore works on this process?
Wiki User
∙ 12y ago
yes
Wiki User
∙ 12y ago
Add your answer:
Earn +20 pts
What is the name given to the process of signaling with two flags?
Semaphore is one such system.
What does it mean to lose your coherent thought process?
Losing your coherent thought process typically refers to experiencing confusion, disorientation, or difficulty expressing yourself clearly. This can happen due to various factors such as fatigue, stress, illness, or certain neurological conditions, impacting your ability to think logically and cohesively. It is important to address the underlying cause and seek support if you find yourself consistently struggling with coherence.
How can semaphore be used to enforce mitual exclusion?
semaphore is a variable providing mutual exclusion in following manner- -It consist of two function called wait and signal, wait() { while(semav==0); semav--; } signal() { semav++; } where semav is semaphore. we apply wait() and signal() in following manner- while(true) { <entry section>; wait() <critical section> signal() <Exit section> } note that wait() always comes before signal(), a process is not allowed to execute critical section if the semaphore has a value 0 i.e. at most one process can execute critical section at a time.
Can a multithread solution using multiple user level threads achieve better performance on a multiprocessor system than on a single processor system?
A multithreaded system comprising of multiple user-levelthreads cannot make use of the different processors in a multiprocessorsystem simultaneously. The operating system sees only a single processand will not schedule the different threads of the process on separateprocessors. Consequently, there is no performance benefit associatedwith executing multiple user-level threads on a multiprocessor system.
How does semaphore solve mutual exclusion problem?
Mutual exclusion is an issue in concurrent programming when two concurrent processes are attempting to access the same shared resource and neither can complete their process because the other is blocking it. A semaphore controls access to the shared resource, ensuring that one process is completely finished before a second can access it.
At what stage in the dialectic process are the elements combined to form a coherent whole?
They are combined during synthesis.
What is semaphore in operating system?
Semaphores are devices used to help with synchronization. If multiple processes share a common resource, they need a way to be able to use that resource without disrupting each other. You want each process to be able to read from and write to that resource uninterrupted. A semaphore will either allow or disallow access to the resource, depending on how it is set up. One example setup would be a semaphore which allowed any number of processes to read from the resource, but only one could ever be in the process of writing to that resource at a time.
What is mutually exclusive?
It is one of thecharacteristics of deadlock. When semaphores are used or mutual exclusion, the semaphore has an initial value of 1, and P() is called before the critical section, and V() is called after the critical section as shown below : semaphore-> P(); critical section semaphore-> V(); remainder section let us suppose that one process A is already executing its critical section then it implies that semaphore value at that time is zero. If process B now tries to enter this critical section , it cannot enter the critical section because it will have to wait before semaphore becomes greater than zero. This is possible only when process A executes its signal operation; after executing its critical section.
What is the similarity between semaphore and monitor?
The wait and signal operations on condition variables in a monitor are similar to P and Voperations on counting semaphores. A wait statement can block a process's execution, while a signal statement can cause another process to be unblocked. However, there are some differences between them. When a process executes a Poperation, it does not necessarily block that process because the counting semaphore may be greater than zero. In contrast, when a wait statement is executed, it always blocks the process. When a task executes a V operation on a semaphore, it either unblocks a task waiting on that semaphore or increments the semaphore counter if there is no task to unlock. On the other hand, if a process executes a signal statement when there is no other process to unblock, there is no effect on the condition variable. Another difference between semaphores and monitors is that users awaken by a V operation can resume execution without delay. Contrarily, users awaken by a signaloperation are restarted only when the monitor is unlocked. In addition, a monitor solution is more structured than the one with semaphores because the data and procedures are encapsulated in a single module and that the mutual exclusion is provided automatically by the implementation.(excerpted from http://ei.cs.vt.edu/~cs5204/sp99/monitor.html) The wait and signal operations on condition variables in a monitor are similar to P and V operations on counting semaphores. A wait statement can block a process's execution, while a signal statement can cause another process to be unblocked. However, there are some differences between them. When a process executes a P operation, it does not necessarily block that process because the counting semaphore may be greater than zero. In contrast, when a wait statement is executed, it always blocks the process. When a task executes a V operation on a semaphore, it either unblocks a task waiting on that semaphore or increments the semaphore counter if there is no task to unlock. On the other hand, if a process executes a signal statement when there is no other process to unblock, there is no effect on the condition variable. Another difference between semaphores and monitors is that users awaken by a V operation can resume execution without delay. Contrarily, users awaken by a signal operation are restarted only when the monitor is unlocked. In addition, a monitor solution is more structured than the one with semaphores because the data and procedures are encapsulated in a single module and that the mutual exclusion is provided automatically by the implementation.(excerpted from http://ei.cs.vt.edu/~cs5204/sp99/monitor.html)
Can semaphore be used by user process or only reserved for operating system?
Absolutely. Just because the OS is generally real time and kernel priority doesn't mean that a user process can't use a semaphore. After all there are real time user processes and they need to signal or block each other. And user processes can get into a deadly embrace situation as well; it doesn't mean the computer is down, but the user processes are stuck and will have to be killed in order to get out of the deadly embrace.
What is semaphores?
Semaphores are any means of communication when flags or lights are employed to communicate . For example , semaphore flags are used to convey messages from one ship to another and traffic lights are a means in which to communicate a signal to traffic . See related link below .
What are the limitations of the distributed system?
1. Absence of global clock... so that no synchronization among processes. 2. Absence of dynamic memory.... So at a particular time a process can only get partial & coherent state Or complete & incoherent state of the distributed system. Coherent:- recorded state of all the processes at any given time
