Question on computer architecture


#1

consider a disk with an advirtised average seek time of 4 ms,rotation spped of 15,00 rpm,and 512-byte sectors with 500 sectors per track.suppose that we wish to read a file consisting of 2500 sectors for a total of 1.28 Mbytes.then estimate the total time for the transfer.


#2

We just want to find transfer time

15000 revolution in 60 sec

1 revolution in 60/15000 or

1 revolution in 4 mili second

1 revolution = covering one entire track = 500 sector

500 sector = 4 mili second

1 sector = 8 micro second

Now there are 2 different things 1) 2500 sectors so time = 2500* 8 mili seconds = 20 mili second

  1. 1.28 MB= 1342177.28 Bytes or 2621.44 sectors = 2622 sectors = 20.976 mili seconds

Total time case 1) 4 + 2 +20= 26 ms or case 2) 4+2+20.976=26.976 ms