Chapter 6

A visually appealing graphic representing operating systems concepts, highlighting critical sections, concurrency, and synchronization mechanisms in a digital style with abstract patterns and computer elements.

Understanding Critical Sections and Race Conditions

This quiz is designed to test your knowledge on critical sections in operating systems and their impact on concurrent processes. Dive into the intricacies of synchronization mechanisms, memory models, and the architecture of concurrent programming.

Key Topics Covered:

Mutual Exclusion
Race Conditions
Hardware Instructions
Memory Models

14 Questions4 MinutesCreated by CodingFox234

An undesirable situation that occurs when two or more processes access and manipulate data concurrently

Concurrency

Parallelism

Race condition

Critical-section problem is

A code segment that can be accessed by only one process at a time

A protocol that the processes can use to synchronize their activity so as to cooperatively share data

A solution to the critical-section problem must satisfy the following 3 requirements

1-Mutual Exclusion 2-Progress 3-Unbounded Waiting

1-Mutual Exclusion 2-Progress 3-Bounded Waiting

1-Starvation 2-Progress 3-Mutual Exclusion

The description of Mutual Exclusion is

If process Pi is executing in its critical section, then no other processes can be executing in their critical sections

If no process is executing in its critical section and there exist some processes that wish to enter their critical section, then only those processes can participate in deciding which will enter its critical section next

A bound must exist 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

Many kernel-mode processes may be active in the operating system. So, the code implementing an OS (kernel code) is subject to several possible _______

False terminations

Overlappings

Race conditions

What are the two general approaches that are used to handle critical sections in operating systems?

1-Preemptive Kernels 2-Non Preemptive Kernels

1-RollBack 2-Starvation

Which of the following belong to Preemptive Kernels? Multiple answers

Allows preemption of process when running in kernel mode

Allows a kernel-mode process to run until it exits kernel mode, blocks, or voluntarily yields CPU

Specially difficult to design

Not feasible solution for SMP architectures

Essentially free of race conditions on kernel data structures

Makes the system more responsive

Memory model is

An instruction that forces any change in memory to be propagated (made visible) to all other processors

How a computer architecture determines what memory guarantees it will provide to an application program

What are hardware instructions?

Commands that allow the operating system to enable or disable some hardware

Instructions that allow us to either test-and-modify the content of a word, or to swap the contents of two words atomically

The test-and-set is an instruction used to

Play with Ghazy's feet

Test a memory location and set a new value as an atomic operation

Write to a memory location and return its old value as a single atomic operation

Which of the following properties belong to the swap and compare instruction

Returns the original value of passed parameter

Set the new value of passed parameter to true

Set the variable value the value of the passed parameter new_value but only if *value == expected is true.

Which of the following is the least complicated way to solve the critical section problem

Test-and-set

Swap and compare

Semaphore

Mutex lock

Chapter 6

Understanding Critical Sections and Race Conditions

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