Paper 2 CS · UNIT 04 · MOCK TEST

Mock 9 – Indexing, Storage & File Organisation

Unit 4: Database Management Systems · 18 questions · about 21 minutes. Press End Mock any time to see your score and the correct answers.

All 11 topic-wise mocks in this unit

0 / 18 answered 00:00

Q1. Which of the following statements is/are NOT CORRECT?
(A) The first record in each block of the data file is known as the actor record.
(B) A dense index has index entries for every search-key value in the data file.
(C) Searching is harder in a B+ tree than in a B-tree as all external nodes are linked to each other.
(D) In extendible hashing, the size of the directory is 2^(d−1), where d is the global depth.
Choose the correct answer from the options given below:

A(A), (B) and (C) Only B(A), (C) and (D) Only C(A), (B) and (D) Only D(A), (B), (C) and (D) Only

Q2. The total cost of retrieving records in sorted order using an unclustered B+ tree is (P = average number of records per data page, N = number of data pages, F = ratio of the size of a data entry to the size of a data record)

A(F × N) + P B(F + P) × N CF × N × P DF + P/N

Q3. If S1 is the total number of modules defined in the program architecture, and S3 is the number of modules whose correct function depends on prior processing, then the number of modules not dependent on prior processing is:

A1 + (S3 / S1) B1 – (S3 / S1) C1 + (S1 / S3) D1 – (S1 / S3)

Q4. Indexed/grouped allocation (of disk blocks to a file) is useful because:
(A) It supports both sequential and direct access.
(B) The entire data block is available for data (no pointers embedded in it).
(C) It does not require a lot of space for keeping pointers.
(D) It has no external fragmentation.

A(A) only B(B) and (C) only C(B) only D(A), (B) and (D) only

Q5. A moving-head disk has 200 tracks, numbered 0 to 199. The head has just finished a request at track 125 and is currently at track 143 (so it is moving in the direction of increasing track numbers). The pending request queue, in FIFO arrival order, is: 86, 147, 91, 177, 94, 150, 102, 175, 130. What is the total head movement (in cylinders) to service all these requests using the SCAN algorithm?

A259 cylinders B169 cylinders C154 cylinders D264 cylinders

Q6. A disk head is currently at cylinder 50. The pending requests, in the order they arrived, are for cylinders: 4, 34, 10, 7, 19, 73, 2, 15, 6, 20. Using the Shortest-Seek-Time-First (SSTF) disk scheduling policy, and given that it takes 1 ms to move the head between two adjacent cylinders, what is the total time needed to service all the requests?

A119 ms B120 ms C142 ms D146 ms

Q7. In a file allocation system, the following allocation schemes are used: (A) Contiguous allocation, (B) Indexed allocation, (C) Linked allocation. Which allocation scheme(s) will NOT suffer from external fragmentation?

A(A) and (B) only B(A) only C(B) and (C) only D(C) only

Q8. Suppose a Linux file system has a block size of 2K bytes, a disk address is 32 bits, and an i-node contains the disk addresses of the first 12 direct blocks of a file, one single-indirect block, and one double-indirect block. Approximately, what is the largest file that can be represented by an i-node?

A513 Kbytes B513 Mbytes C537 Mbytes D537 KBytes

Q9. A disk queue has requests for I/O on cylinders 98, 183, 37, 122, 14, 124, 65, 67, with the disk head currently at cylinder 53. Using the shortest seek time first (SSTF) disk scheduling algorithm, what is the total head movement (in cylinders) needed to service all requests?

A224 B248 C236 D240

Q10. In the ________ disk scheduling algorithm, the disk head moves from one end of the disk to the other, servicing requests along the way. When it reaches the other end, it immediately returns to the beginning of the disk without servicing any requests on the return trip.

ALOOK BSCAN CC-LOOK DC-SCAN

Q11. Which of the following statements about the UNIX file system is NOT correct?

AThe super block contains the number of i-nodes, the number of disk blocks, and the start of the list of free disk blocks. BAn i-node contains accounting information as well as enough information to locate all the disk blocks that hold the file's data. CEach i-node is 256 bytes long. DAll files and directories are stored in data blocks.

Q12. A disk head is initially positioned at track 32. The disk I/O request queue, in arrival order, is: 98, 37, 14, 124, 65, 67. Using the FCFS disk-scheduling algorithm, find the total number of head movements (in tracks) required to service all requests.

A320 B322 C321 D319

Q13.

The order of a leaf node in a B+ tree is the maximum number of (value, data record pointer) pairs it can hold. Given a block size of 1K bytes, a 7-byte data record pointer, a 9-byte value field and a 6-byte block pointer, what is the order of the leaf node?

A63 B64 C67 D68

Q14.

A B tree indexes a database file with search key 10 bytes, block 1024 bytes, record pointer 9 bytes and block pointer 8 bytes. If K is the order of the internal node and L the order of the leaf node, (K, L) =

A(57, 53) B(50, 52) C(60, 64) D(34, 31)

Q15.

Which of the component module of DBMS does rearrangement and possible ordering of operations, eliminate redundancy in query and use efficient algorithms and indexes during the exceution of a query?

Aquery compiler Bquery optimizer CStored data manager DDatabase processor

Q16.

Data scrubbing is

AA process to reject data from the data warehouse and to create the necessary indexes. BA process to load the data in the data warehouse and to create the necessary indexes. CA process to upgrade the quality of data after it is moved into a data warehouse. DA process to upgrade the quality of data before it is moved into a data warehouse.

Q17.

A clustering index is defined on the fields which are of type

Anon-key and ordering Bnon-key and non-ordering Ckey and ordering Dkey and non-ordering

Q18.

In a Hierachical database, a hashing function is used to locate the ________.

ACollision BRoot CForeign Key DRecords

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