MCA - 1203 - 2413/ 1/03
M.C.A. DEGREE EXAMINATION.
First Year Second Semester
File Structures - 2003
(Effective from the admitted batch of 2000 01)

Time: Three hours
Maximum: 75 marks

First question is compulsory.
Answer any FOUR from the remaining.
All questions carry equal marks.
Write all parts of any question at one place.

1. Write briefly on the following.
(a) Fragmentation.(2)
(b) Byte count field. (2)
(c) Cluster. (2)
(d) In the context of CDROM, what does X mean and its value? (2)
(e) Self describing files. (2)
(f) Inverted list. (2)
(g) Difference between file and data structures. (2)
(h) Block 1/0. (1)

2. Explain with help of a diagram, the layers of procedure involved in transmitting a byte from a programmer's data area to a file called text file on disk. (15)

3. What are the most common ways of adding structure to files to maintain the identity of fields? Explain. (3+12)

4. (a) How many comparisons would be required on the average to find a record using sequential search in a 1,00,000 record disk file? If the record is not in the file, how many comparisons are required? If the file is blocked so that 50 records are stored per block, how many disk accesses are required on average? What if only one record is stored per block? (7)

(b) Explain the interaction between file organization and file access. (8)

5. How would you maintain a sequence set of indexed sequential file and simple prefix B+ tree? (7+8)

6. (a) What is hashing? (3)
(b) How collisions occur? What are problems caused by them? (7)
(c) Explain a simple hashing algorithm. (5)
7. (a) Explain how extendible hashing works. (7)
(b) With help of diagram, how tries will be implemented? (8)

8. (a) Explain a file system on CDROM. (7)
(b) What are the design aspects of hashed files on CDROM? (8)