C191 Operating Systems for Programmers Practice Questions - Set 1 - Part 2

Correct Answer: To cache recently used page table entries

The TLB is a high-speed cache used to store recent translations of logical to physical addresses, speeding up memory access for frequently accessed pages.

Correct Answer: First In First Out

FIFO page replacement works by removing the oldest page from memory when a new page needs to be loaded, regardless of the page's usage frequency.

Correct Answer: To reduce memory usage for large address spaces

Multi-level paging divides the page table into smaller levels to reduce the amount of memory needed to store large page tables for processes with large address spaces.

Correct Answer: Shortest Job Next

In the Shortest Job Next (SJN) scheduling algorithm, longer processes may be starved if shorter processes continuously arrive and are prioritized over them.

Correct Answer: A part of a program that accesses shared resources and must be executed atomically

A critical section is a part of a program that accesses shared resources and must be executed without interference from other processes to avoid race conditions.

Correct Answer: Resource allocation graph

A resource allocation graph helps detect and prevent deadlock by visually representing the allocation of resources and the requests made by processes.

Correct Answer: When a process waits indefinitely for CPU time

Starvation occurs when a process is continually overlooked by the CPU scheduler, often because higher-priority processes are consistently given preference.

Correct Answer: To hold a fixed-size block of physical memory

A frame is a fixed-size block of physical memory used to store a page of a process's virtual memory, enabling the efficient mapping of virtual to physical addresses.

Correct Answer: Preemptive scheduling can interrupt processes, while non-preemptive cannot

In preemptive scheduling, the operating system can interrupt a process to allocate the CPU to another process, whereas non-preemptive scheduling allows processes to run to completion before switching.

Correct Answer: A process that spends more time waiting for I/O than CPU execution

I/O-bound processes spend most of their time waiting for input/output operations to complete, using little CPU time compared to CPU-bound processes.

Correct Answer: A unit of CPU execution within a process

A thread is the smallest unit of execution within a process, allowing multiple threads to run concurrently within the same process and share resources.

Correct Answer: It allows concurrent execution of tasks within the same process

Multithreading allows different parts of a program to run concurrently, improving the overall efficiency of tasks that can be performed in parallel.

Correct Answer: Segmentation

In segmentation, memory is allocated in segments, which can grow or shrink dynamically as the process requires, without the need for contiguous memory space.

Correct Answer: The operating system swaps the page into memory

In demand paging, when a page is not present in memory and a process tries to access it, a page fault occurs, and the operating system brings the required page into memory from secondary storage.

Correct Answer: A synchronization problem where a buffer has limited capacity

The bounded buffer problem is a synchronization issue where producers and consumers must share a fixed-size buffer, requiring coordination to avoid buffer overflows or underflows.

Correct Answer: To store processes that are ready to run but waiting for CPU time

The ready queue holds processes that are ready for execution but are waiting for the CPU to become available, ensuring efficient scheduling.

Correct Answer: To signal and synchronize access to shared resources

Semaphores are synchronization primitives used to control access to shared resources by multiple processes, ensuring that resources are not accessed simultaneously by competing processes.

Correct Answer: To decrease the semaphore value and possibly block the process

The 'wait()' operation decreases the value of a semaphore. If the semaphore’s value becomes negative, the process is blocked until the resource becomes available.

Correct Answer: A deadlock problem involving multiple philosophers

The dining philosophers problem is a classic example of a synchronization issue involving shared resources, where deadlock or starvation can occur if philosophers (processes) compete for limited forks (resources).

Correct Answer: To synchronize access to shared resources between multiple processes or threads

A semaphore is a synchronization tool used to manage concurrent access to shared resources by multiple processes or threads, ensuring that critical sections of code are accessed safely and without conflicts.