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Calculate the total time required to read 35 sectors on a 2-sided floppy disk. Assume that each track has 8 sectors and the track-to-track step time is 8 milliseconds. The first sector to be read is sector 3 on track 10. Assume that the diskette is soft sectored and the controller has a 1-sector buffer. The diskette spins at 300 RPM and initially, the head is on track 10.
in Operating System
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Is it out of syllabus?
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this question does not specify the location of  35 sectors where to read from?

if we assume the time to read  a sector is 1/40 sec

then total time taken  assuming that 35 sectors are distributed somewhat evenly is 8*5 millisec +35/40sec

2 Answers

2 votes

The diskette spins at 300 RPM and initially 

so 300 rpm --> 

1 track =1/300 minute

=60/300 seconds 

=1/5 seconds

so one sector =1/40 seconds

now given that 35 sector and started from the sector 3 on track 10th

so the distribution of sector which we have to read  is    6,8,8,8,5 

means first we read 6 sector of track 10th 

after that 8 sector track 11th

after that 8 sector track 12th

after that 8 sector track 13th

after that 5 sector track 14th 

Given:the track-to-track step time is 8 milliseconds

we have to read the data from the 5 track (that is 6,8,8,8,5)

so total time to move from one track to another for these five track =4*8 milliseconds=32ms

and total time to read 35 sectors =35/40 s=35000/40 ms=875 ms

so total time=875+32=907 ms

 


edited by
0
What is 6,8,8,8,5 in your solution and how it came
0

@anchitjindal07 we have to read the data from the five track that is 6,8,8,8,5

because we have total 35 sector which we have to read and starting is from 3rd sector of 10th track 

so first we read 6 sector of track 10th 

after that 8 sector track 11th

after that 8 sector track 12th

so on 

at the end we left only 5 sector  

1

@Satbir

@Lakshman Patel RJIT

@techbd123

@srestha ma'am

Should we go through this question for GATE purpose & if we should Can you verify the given solution.

1
Why average latency is not cosidered?? As we have to first move to sector 3 on the track 10.
–2 votes
Arjun Sir need answer for the above questions
0
What about overhead of controller ( 1 sector delay ) & rotational latency ?

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