Operating System Interview Questions and Answers
Question - 11 : - What are the disadvantages of Microkernels?
Answer - 11 : - Following are the main disadvantages of Microkernels. Usually these disadvantages are situation based.
a. Larger running memory footprint
b. Performance loss due to the requirement of more software for interfacing.
c. Difficulty in fixing the messaging bugs.
d. Complicated process management.
Question - 12 : - What is a command interpreter?
Answer - 12 : - t is a program that interprets the command input through keyboard or command batch file. It helps the user to interact with the OS and trigger the required system programs or execute some user application.
Command interpreter is also referred to as:
- Control card interpreter
- Command line interpreter
- Console command processor
- Shell
Question - 13 : - Explain the basic functions of process management.
Answer - 13 : - Important functions of process management are:
- Creation and deletion of system processes.
- Creation and deletion of users.
- CPU scheduling.
- Process communication and synchronization.
Question - 14 : - What do you know about interrupt?
Answer - 14 : - Interrupt can be understood as a signal from a device causing context switch.
To handle the interrupts, interrupt handlers or service routines are required.
The address of each Interrupt service routine is provided in a list which is maintained in interrupt vector.
Question - 15 : - What is a daemon?
Answer - 15 : - Daemon - Disk and execution monitor, is a process that runs in the background without user’s interaction. They usually start at the booting time and terminate when the system is shut down.
Question - 16 : - How would you identify daemons in Unix?
Answer - 16 : - The name of daemons usually end with 'd' at the end in Unix.
- For e.g. httpd, named, lpd.
Question - 17 : - What do you mean by a zombie process?
Answer - 17 : - These are dead processes which are not yet removed from the process table.
It happens when the parent process has terminated while the child process is still running. This child process now stays as a zombie.
Question - 18 : - What do you know about a Pipe? When is it used?
Answer - 18 : - It is an IPC mechanism used for one way communication between two processes which are related.
A single process doesn't need to use pipe. It is used when two process wish to communicate one-way.
Question - 19 : - What is a named pipe?
Answer - 19 : - A traditional pipe is unnamed and can be used only for the communication of related process. If unrelated processes are required to communicate - named pipes are required.
It is a pipe whose access point is a file available on the file system. When this file is opened for reading, a process is granted access to the reading end of the pipe. Similarly, when the file is opened for writing, the process is granted access to writing end of the pipe.
A named pipe is also referred to as FIFO or named FIFO.
Question - 20 : - What are the various IPC mechanisms?
Answer - 20 : - PC - Inter Process Communication.
Various IPC mechanisms are:
a. Sockets
b. Pipes
c. Shared memory
d. Signals
e. Message Queues