AMCAT Operating Systems Fundamentals

Question 1

Which of the following scheduling algorithms can lead to starvation of low-priority processes?

Accepted Answer

Priority Scheduling (without aging)

Answer

In Priority Scheduling without aging, low-priority processes may wait indefinitely if higher-priority processes keep arriving. This is called starvation. FCFS processes jobs in order (no starvation), RR gives each process a time slice (no starvation), and while SRTF can cause starvation, Priority Scheduling is the classic example.

Question 2

What is the primary difference between a process and a thread?

Accepted Answer

Threads within the same process share memory space, while processes have separate memory spaces

Answer

The fundamental difference is in memory: threads within the same process share the same address space (heap, global variables, code), while processes have completely separate memory spaces. This makes inter-thread communication faster but also introduces synchronization challenges.

Question 3

In virtual memory management, what is a page fault?

Accepted Answer

An event that occurs when a program accesses a page that is not currently in physical memory (RAM)

Answer

A page fault occurs when a running process tries to access a memory page that is mapped in its virtual address space but is not currently loaded into physical RAM. The OS then loads the required page from secondary storage (disk) into RAM, which causes a significant delay.

Question 4

Which of the following is NOT a necessary condition for deadlock according to Coffman's conditions?

Accepted Answer

Preemption

Answer

The four necessary conditions for deadlock (Coffman conditions) are: Mutual Exclusion, Hold and Wait, No Preemption, and Circular Wait. 'Preemption' (the ability to forcibly take resources) actually prevents deadlock. It is 'No Preemption' (resources cannot be forcibly taken) that enables deadlock.

Question 5

What is the purpose of a semaphore in operating systems?

Accepted Answer

To synchronize concurrent processes and control access to shared resources

Answer

A semaphore is a synchronization primitive used to control access to shared resources in a concurrent system. It uses a counter and two atomic operations (wait/signal or P/V) to ensure that critical sections are accessed safely, preventing race conditions.

AMCAT Practice Test

AMCAT Practice Test

AMCAT Operating Systems Fundamentals