SSS 2 Computer Notes

Senior Secondary School (SSS) Two Lesson Notes in computer studies/ICT have been prepared on the following topics below.

Computer Files

A computer file is defined as the smallest meaningful unit of data representation within a computer.
A computer file is a block of arbitrary information, or resource for storing information, which is available to a computer program and usually on some kind of durable storage....

Handling Computer Files

Following are some of the basic file operations:
1. Create: To make a new file
2. Delete: To remove a file from a disk
3. Retrieve: To find a file and bring it back
4. Copy: To produce a file so that it is the same as the original piece of work
5. View: To see the files in a folder
6. Update: A manipulation involving adding, modifying, or deleting data to bring a file up-to-date...

Word Processing

Word Processing: Word processing means using the computer to create, edit, and print document.
Word processor: A word processor is an electronic device or computer software application, which performs the task of composition, editing, formatting, and printing of documents.
Text Document: Text document is something written, printed, or online document that presents data in the form of an articles, letter, memorandum, report, etc....

Spreadsheets

A spreadsheet is a computer program or software which allows calculations to be carried out on several cells that have numbers
Examples of Spreadsheet
1. iWork Numbers – Apple Office Suite
2. Lotus 1-2-3
3. OpenOffice – Calc
4. Lotus Symphony – Spreadsheets
5. Microsoft Excel...

Central Processing Unit

The Central Processing Unit (CPU) also known as the microchip or the microprocessor (or processor for short) is the electronic circuitry within a computer that carries out the instructions of a computer program.
This is the brain or heart of the computer. The main objective of the CPU is to perform mathematical calculations on binary numbers...

Memory Unit

i. The memory unit is part of the computer that holds data and instructions for processing.
ii. It may also be defined as the storage space in the computer where data to be processed and instructions required for processing are stored.
Although closely associated with the central processing unit, memory is separated from it....

Logic Circuit I (Standard Single Logic Gate)

1. A logic gate is an elementary building block of a digital circuit.
2. It is also defined as an electrical circuit, that performs one or more logical operations on one or more input signals.
3. Logic gates are devices that implement Boolean functions, i.e. it does a logic operation on one or more bits of input and give a bit as an output....

Logic Circuit II (Aternative Logic Gate)

Alternative logic gates are those that are the combination of two logic gates.
Types of Alternative Logic Gates
There are generally two types

1. NAND gate
2. NOR gate ...

Computer Data Conversion

Data conversion is the transformation of computer data from one format to another.
Registers Registers are temporary storage areas for instruction or data. It can also be defined as a special, high-speed storage area within the CPU. Registers are not part of the memory; rather they are special additional storage locations that offer the advantage of speed. Register works under the direction of the control unit to accept, hold and transfer instruction or data and perform arithmetic or logical comparison at high speed. The register is the fastest memory available for use in the PC because they are hard-wired right into the processor logic. ...

System Development Life Cycle (SDLC)

The system development life cycle can be defined as a project management technique that divides complex projects into smaller, more manageable segments or phases.
A system development life cycle has three primary objectives: To ensure that high-quality systems are delivered, to provide strong management controls over the projects, and to maximize the productivity of the systems staff....

Program Development

A program is a set of instructions that are executed by the CPU.
A program can also be defined as an organized list of instructions that when executed cause the computer to behave in a predetermined manner. Without a program the computer is useless. ...

Algorithm and Flowchat

Algorithm can be defined as a set of rules and sequential steps that define how a particular problem can be solved in finite and ordered sequences.
Function of Algorithms
An algorithm generally takes some input, carries out several effective steps in a finite amount of time, and produces some output. ...

BASIC Programming II (Built-in Functions)

A function is a structure that simplifies a complex operation into a single step
BASIC built-in functions are predefined functions that perform a wide range of operations.
BASIC Built-in Functions

BASIC has several built-in functions that greatly extend its capability. They include the following:
SQR Function: The SQR function calculates the square root of a number. The general form of the function is SQR(X) ...

Internet

Internet is a worldwide network of computers that share information. It is also defined as a global system of interconnected computer networks that use the Internet protocol suite to link devices worldwide. ...

Electronic Mail (E-mail)

Electronic mail, commonly called email or e-mail, is a method of exchanging digital messages from an author to one or more recipients.
It can also be defined as a system for sending and receiving messages electronically over a computer network.
E-mail Services
The following are services provided by email
a. Sending/receiving emails ...