SSS TWO WEEK ONE LESSON NOTE (ICT_223)

 

Ss2

TOPIC: CONCEPT OF COMPUTER FILES

Introduction

Many tasks in an information-oriented society require people to deal with voluminous data and to use computers to deal with this data efficiently and speedily.

FILE TERMINOLOGIES

1.    Record: is a collection of related fields that can be treated as unit from an application point of view.

2.    Field: is an elementary data item characterized by it’s size, length and type.

3.    Data item: refers to a single unit of values e.g roll numbers, name, date of birth, age, etc. the three types of data item are numeric, alphabetic and alpha-numeric.

TYPES OF FILE ORGANIZATION

The available methods include:

1.    Serial file organization: A serial file is one in which the information or files stored in it have been added in the order in which they occurred or have been saved.

2.    Sequential file organization: A sequential file contains records organized by the order in which they were entered. The order of the records is fixed. Records in sequential file can be read or written sequentially.

3.    Indexed sequential file organization: Records in indexed sequential files are stored in the order that they are written to the disk. Records can be retrieved in sequential order or in a random order using a numeric index to represent the record number in the file.

4.    Random file organization: Random files are record-based files with an internal structure that supports “direct access” by record number.

 

METHODS OF ACCESSING FILES

a)    Serial access

b)   Random access

c)    Sequential access

Comments

Post a Comment

Popular posts from this blog

JSS 2 WEEK TWO LESSON NOTE_FIRST TERM 2023

Image
  Jss2 TOPIC: CLASSIFICATION OF COMPUTER BY GENERATION OBJECTIVE At the end of this topic you should be able to:  1. List the criteria for classifying computers.          I.                   2. State the features of computers classified based on technological age. Introduction Computers can be classified into different categories based on different criteria. Basically, computers can be classified based on the following criteria: 1.      Size. 2.      Types 3.      Generation 4.      Purpose or versatility Based on the technological Age of the computer, computers can be classified into: ·         First generation ·         Second generation ·         Th...
Read more

SSS TWO WEEK TWO LESSON NOTE (ICT_223)

Image
  Ss2 TOPIC:   HANDLING COMPUTER FILES Introduction File operation deals with the physical movement of data in and out of files. User programs effectively use file operations through appropriate programming language syntax. The file management system manages the independent files and acts as the software interfaces between the user programs and file operations. Basic Operations of Computer Files 1.     Insertion: records must be inserted at the place dictated by the sequence of the keys. As   obvious, direct insertion into the main data file would   lead to frequent rebuilding of the file. This problem could be mitigated by reserving overflow areas in the file for insertions. But this leads to wastage of space and also the overflow areas may also be filled. 2.     Deletion: deletion is the reverse of insertion. The space occupied by the record should be free for use. 3.     Updating: updating is a combinat...
Read more

JSS ONE WEEK THREE LESSON NOTE (ICT_223)

Image
  Jss1 TOPIC:   MASTERY OF THE KEYBOARD Introduction A computer keyboard is the most commonly used input device. It is defined as the set of typewriter-like keys that enables you to enter data into a computer or other devices. Computer keyboard are similar to electric-typewriters but contain additional typing keys. The standard arrangement of alphabetic keys on the keyboard is known as the QWERTY. The computer keyboard could be wired or wireless. Types of keyboard There are different types of keyboard depending on what they are used for. Some have more keys than the others. Keyboards also come in different shapes but basically a keyboard has regular shape. The types of keyboards are: a)      Enhanced keyboard b)     Standard keyboard   c)      Windows keyboard d)     AT keyboard   Sections of the Keyboard The keyboard is divided into the following sections: ...
Read more