BASIC COMPUTER OPERATION

Introduction

1.     What is a computer?

2.     Types of computers

3.     Hardware and Software

4.     Basic Operations

5.     Data Sizes and Speeds

	What is a computer?
	Definitions A computer is a machine that manipulates data according to a list of instructions called a program. A computer can also be defined as an electronic machine that accepts input (data), processes it and gives out results (information). A program in memory manages the processing. It can make use of data or information stored in memory and remember the results of the processing for later use, again in memory.
	Types of Computers
	Supercomputer Supercomputers are fast because they are actually many computers working together.
	Mainframe Mainframes are computers in which all the processing is done centrally, and the user terminals are called "dumb terminals".
	Server Servers are similar to mainframes in that they serve many uses with the main difference that, usually, the users (called clients) do much of their own processing. The server processes are devoted to sharing files and managing access rights. A server is a central computer that contains collections of data and programs. Also called a network server, this system allows all connected users to share and store electronic data and applications. Two important types of servers are file servers and application servers.	A server with clients. This diagram could also be used for the mainframe, if the client computers were dumb terminals.
	Cloud Computing "The cloud" is not a single computer system. It just a distributed computing on internet or delivery of computing service over the internet. In cloud computing, your PC acts as a client, perhaps with little more hardware and software than is needed to run an operating system and a web browser. Cloud applications are run on some (unknown) application server in the Internet and your data is stored on some (unknown) file server in the Internet.
	Workstation A single computer that is connected to another computer or network. A workstation has no important function and is not a necessity for a network to operate. A workstation is only needed for a single user to connect to the network.
	Personal Computer or PC PC is an abbreviation for a Personal Computer, it is also known as a Microcomputer.
Hardware
Software Software, commonly known as programs, consists of all the electronic instructions that tell the hardware how to perform a task. These instructions come from a software developer in the form that will be accepted by the platform (operating system + CPU) that they are based on. Practical computer systems divide software systems into two major classes: System software: Helps run computer hardware and computer system itself. System software includes operating systems, device drivers, diagnostic tools and more. System software is almost always pre-installed on your computer. Application software: Allows users to accomplish one or more tasks. Includes word processing, web browsing and almost any other task for which you might install software. (Some application software is pre-installed on most computer systems.)		System software on right. Applications on left.
Basic Operations
Input Whatever goes into the computer? Input can take a variety of forms, from commands you enter by keyboard to data from another computer (via a network connection) or device (via direct or network connection). A device that feeds data into a computer, such as a keyboard or mouse, is called an input device. Output Any information (data) that comes out of a computer. Output devices can be other computers, display screens, speakers, and printers.
Storage Computer data storage is referred to as storage or memory, which can save digital data. Examples are (RAM), hard disks, CDs, DVDs and removable flash memory sticks. Permanent, or non-volatile, storage devices do not require power to remember the data stored. The mass storage devices shown above are non-volatile; a loss of power does not affect their ability to retain data. This category also includes ROM (Read Only Memory). Temporary or volatile storage is more often called "memory". A loss of power means that any data stored will be lost irretrievably. When you are using an application, such as a word processor, the data (the document you are working on) is stored in RAM (Random Access Memory). If you lose power without explicitly saving your work, you will likely lose data.
Processing The processor is the brain of a computer. It's also called the CPU (Central processing unit) and it is a microchip.

How much is 1 byte, kilobyte, megabyte, gigabyte, etc.?

Bit

A bit is a value of either a 1 or 0 (on or off).

Nibble

A Nibble is 4 bits.

Byte

Today, a Byte is 8 bits.

1 character, e.g. "a" is one byte.

Kilobyte (KB)

A Kilobyte is 1,024 bytes.

Megabyte (MB)

A Megabyte is 1,048,576 bytes or 1,024 Kilobytes

Gigabyte (GB)

A Gigabyte is 1,073,741,824 (2³⁰) bytes. 1,024 Megabytes, or 1,048,576 Kilobytes.

Terabyte (TB)

A Terabyte is 1,099,511,627,776 (2⁴⁰) bytes, 1,024 Gigabytes, or 1,048,576 Megabytes.

Petabyte (PB)

A Petabyte is 1,125,899,906,842,624 (2⁵⁰) bytes, 1,024 Terabytes, 1,048,576 Gigabytes, or 1,073,741,824 Megabytes.

Exabyte (EB)

An Exabyte is 1,152,921,504,606,846,976 (2⁶⁰) bytes, 1,024 Petabytes, 1,048,576 Terabytes,

Zettabyte (ZB)

A Zettabyte is 1,180,591,620,717,411,303,424 (2⁷⁰) bytes, 1,024 Exabytes, 1,048,576 Petabytes,

Yottabyte (YB)

A Yottabyte is 1,208,925,819,614,629,174,706,176 (2⁸⁰) bytes, 1,024 Zettabytes, 1,048,576 Exabytes,