In a computer based information system, state the purpose of the following files and give one example where such a file may re required in a school

28/12/2020

(a) In a computer based information system, state the purpose of the following files and give one example where such a file may re required in a school (8mks)

(i) Report life

A summary file from the main file

(ii) Backup file

Backup also called a security file – are copies of files kept in case the original master file is damaged or lost and cannot be used.

(iii) Reference file

This is a file with a reasonable amount of permanency. Examples of data used for reference purposes are price list, tables of rate of pay, names and addresses.

(iv) Sort file

This is a temporary file that holds records organized in a particular order

(b) State three precautions that should be taken to ensure that diskettes are well stored (3mks)

Avoid physical damage
Avoid bringing diskette close to magnetic fields
Write protect to prevent accidental infection by viruses
Do not eject from computer when the access light is still on

(c) Distinguish between “serial” and “indexed sequential” file organization methods (2mks)

A heap file, sometimes called a pile or serial file is the simplest type of file organization, records are placed in the file in the same order as they were inserted

An index structure is associated with a search key and contains records consisting of the key value and the address of the logical record.

A sorted data file with a primary index is called an indexed sequential file.

The file containing the logical records is called the data file and the file containing the index records is called the index file. The values in the index file are ordered according to the indexing field.

(d) Distinguishing between binary and octal number systems and give an example of each (2mks)

Binary number consists of the digits 0 and 1 e.g. 1000112
Octal numbers consist of eight digits, 0,1,2,3,4,5,6 and 7 e.g. 1278