Test by Bikram | Mock GATE | Test 4 | Question: 52

Question

A DMA module transfers characters to memory (using cycle stealing mode) from a device transmitting at 8800 bps. The processor fetches instructions at the rate of $1$ million instructions per second (1 MIPS).  

The processor will be slowed down due to the DMA activity by _______ % ( up to 2 decimal places ).

Answer 1

$8800 bps$ $=$ $8800/8$ $=$ $1100$ char per sec (by assuming $8 bit$ per char or  byte).

Slow down  is : $( 1100 * 100 / 10^6) = 0.11 %$

Comments

sir thoda sa elaborate krte to achha hota.....

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 in cycle stealing mode, after one byte of data transfer, the control of the system bus is deasserted to the CPU via BG. It is then continually requested again via BR, transferring one byte of data per request, until the entire block of data has been transferred. wikipedia