Top 10 List of Week 07

1. Operating System Process Synchronization
   This article show us about Synchronization. When two or more process cooperates with each other, their order of execution must be preserved otherwise there can be conflicts in their execution and inappropriate outputs can be produced.

2. Race Condition
   This video explain us about race condition. A Race Condition typically occurs when two or more threads try to read, write and possibly make the decisions based on the memory that they are accessing concurrently.

3. Deadlock
   This article explains us about deadlock. Deadlock is a situation that occurs in OS when any process enters a waiting state because another waiting process is holding the demanded resource. Deadlock is a common problem in multi-processing where several processes share a specific type of mutually exclusive resource known as a soft lock or software.

4. Sempahore
   We learn about semaphore in this article. Semaphore is simply a variable that is non-negative and shared between threads. This variable is used to solve the critical section problem and to achieve process synchronization in the multiprocessing environment.

5. Monitor vs Semaphore
   After learnt about semaphore, I found out about monitor. I am curious about it. Monitors are a synchronization construct that were created to overcome the problems caused by semaphores such as timing errors. Only one process can be active in a monitor at a time. Other processes that need to access the shared variables in a monitor have to line up in a queue and are only provided access when the previous process release the shared variables.

6. Producer-Consumer Problem
   In synchronization, there are several problem that may occure. One of problems is producer-consumer. In the producer-consumer problem, there is one Producer that is producing something and there is one Consumer that is consuming the products produced by the Producer. The producers and consumers share the same memory buffer that is of fixed-size. The producer and consumer should not access the buffer at the same time.

7. Peterson’s Algorithm
   There is algorithm to handle the producer-consumer problem. In this article we learn about Peterson’s Algorithm. Producer produce an item and put it into buffer. If buffer is already full then producer will have to wait for an empty block in buffer. Consumer consume an item from buffer. If buffer is already empty then consumer will have to wait for an item in buffer. Implement Peterson’s Algorithm for the two processes using shared memory such that there is mutual exclusion between them. The solution should have free from synchronization problems.

8. Dining Philosopher Problem Using Semaphores
   This article learn about problem occur in semaphore. This problem states that K philosophers seated around a circular table with one chopstick between each pair of philosophers. There is one chopstick between each philosopher. A philosopher may eat if he can pick up the two chopsticks adjacent to him. One chopstick may be picked up by any one of its adjacent followers but not both.

9. Readers-Writers Problem
   There is problem about readers-writer that we learn in this article. The readers-writers problem is used to manage synchronization so that there are no problems with the object data. For example - If two readers access the object at the same time there is no problem. However if two writers or a reader and writer access the object at the same time, there may be problems.

10. Deadlock Prevention
    This article explains three techniques on preventing deadlocks, namely lock ordering, lock timeout, and deadlock detection. There are Lock Ordering, Lock Timeout, and Deadlock Detection. In this article we learn those techniques.