Unix Interview Question and Answers

11. What is called a page fault?
 
  • Page fault is referred to the situation when the process addresses a page in the working set of the process but the process fails to locate the page in the working set.
  • And on a page fault the kernel updates the working set by reading the page from the secondary device.
12. What do you mean by u-area (user area)?
  This contains the private data that is manipulated only by the Kernel. This is local to the Process, i.e. each process is allocated a u–area
13. What are the different types of buffering is supported by UNIX?
 
  • Fuly buffered
  • Line buffered
  • Un buffered
14. What is the purpose of exec functions?
 
  • When a process calls one of the exec functions that process is completely replaced by the new program. The new program stats execution from main function.
  • The processed does not change across an exec because a new process is not created.But this function replaces the current process with new program from disk.
15. Define process group?
 
  • A process group is a collection of one or more processes. Each process group has a unique process ID.
  • A function getpgrp returns the process group id of the calling process.
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