1
GATE CSE 2001
Subjective
+5
-0
Consider a disk with the $$100$$ tracks numbered from $$0$$ to $$99$$ rotating at $$3000$$ $$rpm.$$ The number of sectors per track is $$100.$$ the time to move the head between two successive tracks is $$0.2$$ milliseconds.

(a) Consider a set of disk requests to read data from tracks $$32, 7, 45, 5$$ and $$10.$$ Assuming that the elevator algorithm is used to schedule disk requests, and the head is initially at track $$25$$ moving up (towards larger track numbers), what is the total seek time for servicing the requests?
(b) Consider an initial set of $$100$$ arbitrary disk requests and assume that no new disk requests arrive while servicing these requests. If the head is initially at track $$0$$ and the elevator algorithm is used to schedule disk requests, what is the worst case time to complete all the requests?

2
GATE CSE 2001
MCQ (Single Correct Answer)
+1
-0.3
Consider a set of $$n$$ tasks with known runtimes $${r_1},{r_2},.....\,{r_n}\,\,$$ to be run on a uniprocessor machine. Which of the following processor scheduling algorithms will result in the maximum throughput?.
A
Round -Robin
B
Shortest -Job -First
C
Highest-Response-Ratio-Next
D
First -Come-First-Served
3
GATE CSE 2001
MCQ (Single Correct Answer)
+1
-0.3
A processor needs software interrupt to
A
Test the interrupt system of the processor
B
Implement co-routines
C
Obtain system services which need execution of privileged instructions
D
Return from subroutine
4
GATE CSE 2001
MCQ (Single Correct Answer)
+1
-0.3
A CPU has two modes-privileged and non-privileged. In order to change the mode from privileged to non-privileged
A
A hardware interrupt is needed
B
A software interrupt is needed
C
A privileged instruction (which does not generate an interrupt) is needed.
D
A non-privileged instruction (which does not generate an interrupt) is needed.
EXAM MAP