Made Easy Test Series

Question

Consider a disk drive with the following specifications. 16 surfaces, 128 tracks / surfaces, 256 sectors / track, 512 B / sector, rotations speed 3600 rpm. The disk is operated in cycle stealing mode whereby whenever one byte word is ready it is sent to memory; similarly, for writing, the disk interface reads a 5 byte word from the memory in each DMA cycle. Memory cycle time is 50microsec. The maximum percentage of time the CPU gets blocked during DMA operation is______?

Comments

A similar one came in the gate examinations , check the solution you'll get it :)

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prashant jha 1

yes, just saw a similar question being asked in GATE CS 2005 https://gateoverflow.in/1393/gate2005-70

But i have one doubt here..why are we not multiplying the number of surfaces also while calculating data transfer rate?By default we should consider one Read/Write head for each surface right? so in one rotation, 16 tracks are being read and not only one track, right?Where am I going wrong?

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@Somoshree Datta 5, check this comment your doubt will be clear-

https://gateoverflow.in/2650/gate1995-14?show=150583#c150583

you are right we consider one read/ write head for each surface but for our continence we consider data transfer rate for only one surface otherwise explicitly mentioned.

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got it..thanks Shubhgupta :)