Interview questions for placement in OS with answers
Operating Systems TRUE/FALSE Interview Questions with Answers - 12
1. The kernel on a multiprocessor can use the local disabling of
interrupts (within one CPU) to produce critical sections between the OSs on
different CPUs. 
(a)
TRUE                                                   (b)
FALSE
View Answer
| 
Answer: FALSE.  
Disabling
  interrupts on one CPU doesn’t affect other CPUs. Consequently, other CPUs
  keep executing when a single one has interrupts disabled. | 
2. When designing a multi-threaded application, you must use
synchronization primitives to make sure that the threads do not overwrite each
other’s registers.
(a)
TRUE                                                   (b)
FALSE
View Answer
| 
Answer: FALSE.  
Registers
  are kept in the TCB and are private to each thread. Consequently, one thread
  will not overwrite another thread’s register under normal circumstances.  | 
3. Round robin scheduling provides a latency improvement over
FCFS scheduling for interactive jobs.
(a)
TRUE                                                   (b)
FALSE
View Answer
| 
Answer: TRUE.  
By
  time-slicing jobs, RR scheduling avoids the problem FCFS in which interactive
  jobs can get stuck behind long-running jobs. Round Robin scheduling - Round-robin scheduling allocates each task an equal share of the CPU time. In its simplest form, tasks are in a circular queue and when a task's allocated CPU time expires, the task is put to the end of the queue and the new task is taken from the front of the queue. | 
4. Threads in a process share the same file descriptors 
(a)
TRUE                                                   (b)
FALSE
View Answer
| 
Answer: TRUE.  
Threads
  within a process share the same memory map and hence share all global data
  (static variables, global variables, and memory that is dynamically-allocated
  via malloc or new). List of items that are shared among threads within a process
The items that are shared among threads within a process are: 
 | 
5. Consider two machines A and B of different architectures,
running two different operating systems OS-A and OS-B. Both operating systems
are POSIX compliant. The source code of an application that is written to run
on machine A must always be rewritten to run on machine B.
(a)
TRUE                                                   (b)
FALSE
View Answer
| 
Answer: FALSE.  As mentioned in the question that both the OS are POSIX complaint. Hence, the source code of the application that is written for one machine need not be rewritten for other architecture.
POSIX
  - The Portable Operating System Interface
  (POSIX) is an IEEE standard that helps compatibility and
  portability between operating systems. Theoretically, POSIX compliant source
  code should be seamlessly portable. In the real world, application transition
  often runs into system specific issues. But POSIX compliance makes it simpler
  to port applications which can result in time savings. | 
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