17 Questions
What is the purpose of maintaining data consistency in processes synchronization?
To prevent data inconsistency from occurring
What is the role of the producer in the producer-consumer problem?
Incrementing the counter and producing new items
What is the potential issue associated with concurrent execution of processes in the producer-consumer problem?
Data inconsistency
What is the initial value of the counter in the producer-consumer problem?
0
What is the purpose of the while loop in the producer's code?
To check if the counter is at BUFFER_SIZE
What does the 'out' variable represent in the consumer's code?
The location of the next item to be consumed in the buffer
Which problem involves n processes, each with a Critical Section (CS) where common variables are changed, tables updated, or files written?
The Critical-Section problem
What are the three requirements for Critical-Section solutions?
Mutual exclusion, progress, bounded waiting
Which method uses two shared variables, a boolean flag 'turn', and a flag indicating readiness to enter the Critical Section (CS)?
Peterson's solution
What protects a Critical Section by first acquiring a lock and releasing it?
Mutex locks
Which synchronization method uses an integer variable and atomic wait() and signal() operations for processes?
Semaphores
What are the potential issues associated with semaphores?
Deadlock and starvation
Which solution ensures allowing multiple readers to access a shared data set simultaneously while ensuring only one writer can access it at a given time?
The Readers and Writers problem solution
What is used in the Readers and Writers problem to ensure mutual exclusion between readers and writers?
Mutex locks
What type of variable is used in semaphores to synchronize processes?
Integer variable
Which method provides more sophisticated synchronization methods for processes with atomic wait() and signal() operations?
Semaphores
What is the primary purpose of mutex locks in protecting a Critical Section?
Providing exclusion between multiple processes
Study Notes
- The text discusses solutions to the Critical-Section Problem, where multiple processes need to access shared resources without conflicts.
- The problem involves n processes, each with a Critical Section (CS) where common variables are changed, tables updated, or files written.
- Only one process can be in its CS at a time; others must wait.
- The CS is preceded by an entry section and followed by an exit section, forming the general structure of a process.
- Three requirements for CS solutions: mutual exclusion, progress, and bounded waiting.
- Peterson's solution uses two shared variables, a boolean flag "turn" and a flag indicating readiness to enter the CS.
- In the algorithm for Process Pi, mutual exclusion is ensured by only allowing entry if flag[j] is false or turn equals i.
- Peterson's solution provides proof that the three requirements are met when accessing shared resources.
- Mutex locks protect a CS by first acquiring a lock and releasing it.
- Mutex locks are implemented using a Boolean variable and atomic operations.
- pthread mutexes are another solution, where a mutex is represented by the pthread mutex object.
- Semaphores provide more sophisticated synchronization methods for processes with an integer variable and atomic wait() and signal() operations.
- Deadlock and starvation are potential issues with semaphores.
- POSIX semaphores can be created, waited on, and posted using sem_open(), sem_wait(), and sem_post().
- Parent-child example uses semaphores for synchronization between parent and child processes.
- Readers and Writers problem deals with allowing multiple readers to read a shared data set simultaneously while ensuring only one writer can access it at a given time.
- The solution involves using a shared data semaphore, reader mutex, and writer mutex, as well as an integer read count, ensuring mutual exclusion, progress, and bounded waiting.
Learn about processes synchronization, concurrent access to shared data, and maintaining data consistency through mechanisms to ensure orderly execution of cooperating processes. This quiz covers topics such as the producer-consumer problem and data inconsistency.
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