Operating system

Which of the following is NOT a valid deadlock prevention scheme? (GATE CS 2000) 

• Release all resources before requesting a new resource 

• Number the resources uniquely and never request a lower numbered resource than the last one requested. 

• Never request a resource after releasing any resource 

• Request that all required resources be allocated before execution

Let m[0]...m[4] be mutexes (binary semaphores) and P[0] .... P[4] be processes. Suppose each process P[i] executes the following:

wait (m[i]); wait(m[(i+1) mode 4]);
------
release (m[i]); release (m[(i+1)mod 4]);

This could cause (GATE CS 2000) 

• Thrashing

• Deadlock 

• Starvation, but not deadlock

• None of the above 

Where does the swap space reside? (GATE 2001) 

• RAM 

• Disk

• ROM 

• On-chip cache

Which of the following scheduling algorithms is non-preemptive? (GATE CS 2002) 

• Round Robin 

• First-In First-Out 

• Multilevel Queue Scheduling 

• Multilevel Queue Scheduling with Feedback

Increasing the RAM of a computer typically improves performance because:

• Virtual memory increases 

•  Larger RAMs are faster 

• Fewer page faults occur 

• Fewer segmentation faults occur 

In Operating Systems, which of the following is/are CPU scheduling algorithms?

• Priority

• Round Robin

• Shortest Job First

• All of the mentioned

 In real time operating system ____________

• process scheduling can be done only once

• all processes have the same priority

•  kernel is not required

• a task must be serviced by its deadline period

Whenever a process needs I/O to or from a disk it issues a ______________

• system call to the operating system

• a special procedure

•  system call to the CPU

• all of the mentioned

Thread is a

• Light weight process

• Heavy weight process

• multi process

• i/o process

Which of the following schedules threads?

• virtual memory

• operating system

• CPU

• Input