Peterson's Solution Quiz

A situation where multiple processes or threads access and modify shared data concurrently, leading to unpredictable and potentially incorrect results.

A section of code that can only be executed by one process at a time. It ensures mutual exclusion, preventing data corruption from concurrent access.

A tool that enables processes to synchronize access to shared resources.

A technique used to protect shared data from concurrent access by multiple processes. It ensures that only one process can access the critical section at a time.

A classic problem in concurrent programming where multiple processes need to access and modify a shared resource, but only one process can be in the critical section at a time. The challenge is to ensure that the processes cooperate and access the resource safely.

A memory barrier that ensures that all memory operations before the barrier are completed before any operations after the barrier are executed, preventing out-of-order execution.

An instruction that atomically reads a value from memory, compares it to a given value, and if they are equal, updates the memory location with a new value. It guarantees that the comparison and update happen as a single, indivisible operation.

A type of variable that supports atomic operations, guaranteeing that operations on it happen without interference from other processes.

If no processes are currently in their critical sections, and some processes want to enter, then the selection of which process will enter next should not be postponed indefinitely. At least one of the processes waiting to enter its critical section must eventually be allowed to do so.

Ensuring that processes do not wait forever to enter their critical sections. The selection of the next process to enter a critical section shouldn't be delayed indefinitely.

This approach aims to solve the critical section problem by disabling and enabling interrupts. It's a primitive method with limitations.

This method for two processes uses a shared variable 'turn' to control access to the critical section. The process holding the 'turn' can enter the critical section.

The algorithm for Process Pi ensures that it enters the critical section only when it's its turn (indicated by 'turn' being equal to 'i').

This algorithm mirrors the algorithm for Process Pi, but with the roles of 'i' and 'j' reversed. Process Pj can enter the critical section when 'turn' is equal to 'j'.

This solution guarantees that only one process can be in the critical section at a time. However, it does not address the progress requirement, meaning a process could be perpetually blocked.

The two-process solution ensures mutual exclusion but fails to address the progress requirement because it does not guarantee that a process will eventually enter the critical section.

A programming technique that ensures processes or threads can access shared resources in a controlled and synchronized manner.

A requirement that ensures that if a process wants to enter the critical section, it will eventually be able to do so.

A solution to the critical section problem that uses two shared variables: 'turn' and 'flag', to coordinate access to the critical section.

A programming construct that allows processes to communicate and coordinate their actions.

A type of semaphore with a maximum value of 1, used to implement mutual exclusion. Only one thread can acquire the mutex at a time.

A situation where the order of instructions in a multi-threaded program is unpredictable, leading to unreliable results. This occurs when multiple threads access and modify shared data concurrently without proper synchronization.

An implementation of Peterson's Solution that fails on modern architectures due to instruction reordering (out-of-order execution). It demonstrates the importance of memory barriers in preventing race conditions.

A process where instructions are not necessarily executed in the order they appear in the code. This is a performance optimization technique that can lead to unexpected behavior in multithreaded programs.

In the context of Peterson's solution, the reordering of instructions can lead to both threads entering the critical section simultaneously, violating mutual exclusion and causing potential data corruption.