Basic CS-Operating System [3i Infotech Placement]: Sample Questions 88 - 89 of 89

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Question 88

Operating System
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Short Answer▾

What is buffer cache?

Explanation

Define Buffer Cache
  • Files are stored on hard drive- processes can access these files and create new files.
  • When process requests a file the kernel brings the file into the main memory where user process can change, read, or access the file.
  • The memory location where the file is brought is called the buffer cache.
  • The buffer cache can be regarded as a memory resource- primarily an I/O resource mediating data transfer.
  • A write request can thus be satisfied without accessing the physical device- kernel checks the buffer cache to see if the block, containing the data address, is already in memory.

Question 89

Operating System
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Write in Short

Short Answer▾

What are the reasons for process suspension?

Explanation

  • Swapping:
    • The operating system needs to release sufficient main memory to bring in a ready process.
  • Interactive user request:
    • User wishes to suspend execution of a program for purpose of debugging.
  • Timing:
    • A process may be suspended periodically for the next time interval.
  • Parent process request:
    • A parent processes wishes to suspend execution of descendent to examine or modify the suspended process.

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