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Threads in Operating Systems
Question 1
Consider the following two threads T1 and T2. Initially, a = b = 1. Each statement executes atomically.
T1: a = a + 1;
b = b + 1;
T2: b = 2 * b;
a = 2 * a;
Which lists all possible values of (a, b) after both threads finish?
( GATE 2020 | MCQ )
- A
{(4,4)}
- B
{(3,3), (4,4)}
- C
{(3,3), (4,4), (3,4), (4,3)}
- D
{(2,2), (2,4), (3,3), (3,4), (4,3), (4,4)}
Question 2
Threads are effective only if the CPU is:
- A
Multi-core
- B
Single-core
- C
High speed
- D
Idle
Question 3
Which of the following is shared among all threads in a process?
- A
Stack
- B
Program counter
- C
Register set
- D
Code section
Question 4
Which component is NOT unique to each thread?
- A
Thread ID
- B
Program Counter
- C
Stack
- D
Address space
Question 5
The OS data structure maintained for a thread includes:
( GATE 2016 | MCQ )
- A
Page table, open file table, signal table
- B
Program counter, register set, stack
- C
Both (a) and (b)
- D
Only PCB
Question 6
Which statement about threads is TRUE?
( GATE 2023 | MCQ )
- A
Two threads of the same process cannot run simultaneously on a single-core CPU.
- B
A thread can exist without a process.
- C
Threads share address space but have separate stacks and program counters.
- D
Switching threads of different processes is cheaper than within the same process.
Question 7
Which one of the following is FALSE?
( GATE 2014 | MCQ )
- A
User-level threads are not scheduled by the kernel.
- B
When a user-level thread is blocked, all threads of the process are blocked.
- C
Context switching between user-level threads is faster than between kernel-level threads.
- D
Kernel-level threads cannot share the code segment.
Question 8
Which of the following is FALSE?
( GATE 2002 | MCQ )
- A
Context switching is slower for kernel-level threads than user-level threads.
- B
Blocking one kernel-level thread blocks all related threads.
- C
User-level threads do not require hardware support.
- D
Kernel-level threads can run on different processors.
Question 9
A thread is called a lightweight process because it shares resources with other threads. Which of the following is TRUE?
( GATE 2011 | MCQ )
- A
OS maintains only CPU registers per thread.
- B
OS does not maintain a separate stack per thread.
- C
OS does not maintain virtual memory state per thread.
- D
OS maintains only scheduling information per thread.
Question 10
Main difference between a process and a thread is:
- A
Processes share memory, threads do not
- B
Threads share memory, processes do not
- C
Threads are heavier than processes
- D
Processes are faster to create than threads
There are 12 questions to complete.