121. Poor response time are caused by

Process or busy

High I/O rate

High paging rates

All of these

122. Disk sheduling involves deciding

which disk should be accessed next

the order in which disk access requests must be serviced

the physical location where files should be accessed in the disk

none of these

123. 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. If the scheduling algorithm is the closest cylinder next, then the total seek time will be

360 ms

876 ms

850 ms

900 ms

124. 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

125. 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

126. 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

127. 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

128. 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

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

relative organization

key fielding

dynamic reallocation

hashing

130. A file organization component of a VSAM file is

relative record data set.

keyed sequential data set.

entry sequential data set.

all of these

131. Access time is the highest in the case of

floppy disk

cache

swapping devices

magnetic disks

132. 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

133. 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

134. A file sometimes called a

collection of input data

data set

temporary place to store data

program

135. Primitive disk operating system (POS) manages its disk files in contiguous blocks. A file is saved to the first available space that is large enough to hold the file. Assume that a disk has only 10 contiguous blocks of available free space. Which of the following set of file operations Fa=1, Fb=3, Fc=5, Fd=6 can not be completed given the set of files and file sizes specified below

save (ƒa), save (ƒb), save (ƒd), delete (ƒd), save (ƒc)

save (ƒc), save (ƒa), delete (ƒc), save (ƒd)

save (ƒd), save (ƒb), delete (ƒd), save (ƒc)

save (ƒb), save (ƒa), delete (ƒb), save (ƒd)

136. In MS-DOS, relocatable object files and load modules have extensions

.OBJ and .COM or .EXE respectively

.COM and .OBJ respectively

.EXE and .OBJ respectively

.DAS and .EXE respectively

137. Consider six files F1, F2, F3, F4, F5 and F6 of corresponding sizes 100, 200, 70, 40, 250 and 50 respectively. If the files are stored in such a manner to optimize access time, what will be the approximate average access time of a record from one of the six files on the sequential device ?

131

198

286

433

138. Which type of design problem in file system?

How the file system should look to the user

Algorithm and data structure must be created to map the logical file system onto the secondary storage device

Both (a) and (b)

None of these

139. Consider six files : F1, F2, F3, F4, F5, F6 with corresponding sizes 100, 200, 70, 40, 250 and 50 respectively, the files are to be stored on a sequential device in such a way that as to optimize access time. In what order should the files be stored?

F6, F5, F4, F3, F2, F1

F1 F2, F3, F4, F5, F6

F5, F2, F1, F3, F6 , F4

F4, F6, F3, F1 F2, F5

140. Shared sub-directories and files are example of

a cyclic graph directory

tree structured direction

one level directory

none of these