1. Disk requests come to a disk driver for cylinders 10, 22, 20, 2, 40, 6 and 38, in that order at a time when the disk drive is reading from cylinder 20. The seek time is 6 ms per cylinder. The total seek time, if the disk arm scheduling algorithm is first-come-first-served is

360 ms

876 ms

850 ms

900 ms

2. Disk requests are received by a disk drive for cylinders 5, 25, 18, 3, 39, 8 and 35 in that order. A seek takes 5 m sec per cylinder moved. How much seek time is needed to serve these requests for a Shortest Seek First (SSF) algorithm ? Assume that the arm is at cylinder 20 when the last of these requests is made with none of the requests yet served

125 msec

295msec

575 msec

750 msec

3. The maximum amount of information that is available with one position of the disk access arm for a removal disk pack (without further movement of the arm with multiple heads) is

a plate of data

a cylinder of data

a track of data

a block of data

4. An unpaged or read-ahead cache associates disk domains with the address of the read and continues for a specific length. The major disadvantage of unpaged cache is that

it allows cache domain to contain redundant data

it does not allow writes to be cached

its access time is greater than that of paged caching

read ahead cache domain blocks are necessarily fixed in size

5. If a disk has a seek time of 20 ms, rotates 20 revolutions per second, has 100 words per block, and each track has capacity of 300 words. Then the total time required to access one block is

25

30

40

60

6. The file structure that redefines its first record at a base of zero uses the term

relative organization

key fielding

dynamic reallocation

hashing

7. A file organization component of a VSAM file is

relative record data set.

keyed sequential data set.

entry sequential data set.

all of these

8. Access time is the highest in the case of

floppy disk

cache

swapping devices

magnetic disks

9. A program P reads and processes 1000 consecutive records from a sequential file F stored on device D without using any file system facilities. Given the following: (i) Size of each record = 3200 bytes. (ii) Access time of D = 10 m secs. (iii) Data transfer rate of D = 800 x 103 bytes/sec (iv) CPU time to process each record = 3 m secs. What is the elapsed time of P if F contains unblocked records and P uses one buffer(i.e. it always reads ahead into the buffer)?

12 sec

14 sec

17 sec

21 sec

10. A program P reads and processes 1000 consecutive records from a sequential file F stored on device D without using any file system facilities. Given the following: (i) Size of each record = 3200 bytes. (ii) Access time of D = 10 m secs. (iii) Data transfer rate of D = 800 x 103 bytes/sec (iv) CPU time to process each record = 3 m secs. What is the elapsed time of P if F contains unblocked records and P does not use buffering?

12 sec

14 sec

17sec

21sec