Multiple choice

Buffer blocks are provided to I/O controllers to handle I/O and to

  1. save CPU time

  2. provide multitasking to I/O

  3. engage CPU till I/O is complete

  4. interrupt CPU by I/O devices

  5. none of the above
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

CPU is much faster than the I/O device. A buffer block of 4 K byte means the block can store 4K characters. Writing 4K characters in the block requires very less time for CPU while for I/O requires quite high time for accessing these 4K. CPU becomes free for sufficient time to do other part of programmes after writing a buffer, while I/O controller takes over to send characters and other commends to I/O device independent of CPU. So, the CPU time is saved. 

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