Computer sizes can be classified into 4 categories according to the support they offered namely
super computers
micro computers
mini computer
main frame computers
Micro Computer System
These are also known as personal computers and are the ones mostly found in big and small office, they are normally standalone computers known PC, or Desktop Computers. Micro Computers are small and expensive designed for individual use
These are devices that relay out the processed data for end users to interpret and includes Monitor, printers etc
There are two types of Output
•Hard Copy output - printed on a paper
•Soft Copy Output - Display on the computer monitor also know as (WYSIWYG) output, What You See Is What You Get
Secondary Storage Devices (Auxiliary Devices)
These store the information externally from the computer System Unit. Primary memory is not large enough to hold the data available it is seldom volatile - when power is switched off it also goes off therefore loosing all the data it had stored
Secondary Storage - is non volatile and hence required for long term use for storage back up.
There are three types of storage medium namely
•Magnetic type
•Magnetic Discs
•Optical media
Computer Operating Systems (OS)
Is a set of programmes that controls and supervises computer system hardware and provide interfaces to Application Programmes and uses of computer systems resources. Its purpose is to provide an interface between a user or an application system and the hardware Control programmes manages computers hardware and resources
Control Programmes Performs
•Resource Management - Manages memories and CPU
•Job Memory - Manage different jobs at the same time
•Data management input and output management
Computer Utility Programmes - These perform routine checkups and maintained of the computer e.g.
Disc scanning and defragmentation examples includes
•Disc cleanup
•Disc Defragmenter etc
Service programmes - These provides services to users or programming of computer system e.g language translator programmes
Magnetic Tapes
Typically half inch or quarter inch of plastic writing material coated with magnetic material usually iron oxide, reading of magnetic tapes is sequential.
Magnetic Disc made of metallic printer in which electronic data can be stored reading is sequential or direct.
Advantages of Magnetic Discs
•Direct access to store data
•Faster data transfer speed
•Convenient fro small computers
•Relatively cheaper
There are two types of magnetic Discs
•Floppy Discs (Diskettes) Floppy Disc is a small flexible disc and usually available in 3 1/2 inches and 5 1/4 inches. Each diskette regardless of size is divided in concentric circle, where data is stored is stored. It is also divided into pie shaped wedges called sectors which further specified storage. The number of sectors is determined by dividing formatting process which is control by Computer operating system (OS).
The Operating System labels each sectors of each diskettes with an address so that computer can go directly into specific areas rather than starting at the beginning.
A diskettes maybe single sided where data is recorded mainly one side or double sided which allows information to be recorded and stored on both sides
Advantages of Hard Disc over floppy Diskettes
•Hard Disc has higher rotational speed
•Hard Disc has more storage capacity
•Hard Disc has faster access to storage of data
•Hard Discs
Hard discs are of two types
•Fixed disc system
•Removable cartridge
Computer Optical Technology Media
Involves the use of lacers and are secreted new types of storage media most are read only memory(ROM), however some can be written but they are more expensive to acquire and requires special machines for writing. They have very high memory.
Central Processing Unit - Also known as CPUIs where processing take place. It is an electronic device that serves as the brain of a computer in conjunction with other devices that i.e. input and output device.
Components of a CPU includes
Arithmetic Logic Unit (A.L.U) - Refers to the part where all arithmetic logically functions are performed
Control Unit - Directs sequences of events necessary to execute an instruction by repeating the following four operations
• Fetching
• Decoding
• Executing
• Storing
Primary Memory - This the main storage device in the computer system that stores data temporarily when data is being process
Data Presentation - Computer identify an electrical impulse that is high voltage on and low voltage off e.g. d is represented by 1100100
The one with zero can further be coded Coding is a method where a series of zeros and ones are assigned decimal there are two types of codes namely
• American Standard Code for Information Interchange (ASCII)
The small piece of recognize data by a computer is called a Bit
Bit - Is a single binary value either one (1) or zero(0)
Byte - A group of bits and is the basic unit for measuring memories
Computer Word - Is the number of adjacent bits that can be stored and manipulated as 1 unit, the longer the computer word the faster the speed. The longer the word that Computer can manipulate the greater the data that can be processed
Input - This refers to the process of entering programme data.
Program Which are coded and stored in main memory determine the type of processing to be done, programmes are entered through the Keyboard or access from Auxiliary storage devices
Command - These are keywords and phrases that users input to direct the computer to perform certain activities e.g. quit, print, save etc
User Responses - Instructions that users input in response to questions or messages from the Operating system or application Software
Input Devices - These are peripheral devices used e.g. Keyboard, mouse, Joystick, light pen, touch screen, voice input, Scanner and CDO output to enter data to the computer.
"A capacitor is component that can store electric charge and normally consist of two plates that can are parallel to each other, very close and are separated by an inductor. When a capacitor is connected to a voltage supplied, current flows through the circuit and electrons are stored on one of the capacitor’s plates. On the other plate there would be a shortage of electrons, in this case the capacitor is said to be charged and if its disconnected from the supply, the imbalance between the two plates will remain. If a charged capacitor is connected in a circuit it will for a short time act as a voltage source just like a battery" Click to continue reading Types of capacitors:
We have looked at some basic definition used in computing where we did defined what a computer, We also looked ta the computer history and generation. It is now time to look and computer types available in the market today. Computers are divided into different categories depending on their features and functions.
Since the invention of computers from first generation and fourth generation computers, they have been classified according to their types and how they operate that is input, process and output information. Below you will get a brief discussion on various types of Computers we have click here to continue Types of Computer
Computer can be describe as an electronic device operating under control of instruction stored its control Unit logically processes then store the data.
Data - Refers to numbers, letters, characters or combination therefore entered, analyzed and processed by a computer.
Programme - Refers to a series of instruction that tells a computer what to do.
Software - Refers to progrmmes that may be used in computers. Software are divided into two categories
System Software - These are programs that control and direct the operation of computer hardware. They help users to interrupt with the computer to effectively use his resources examples includes Windows programs like WinNT, Windows 2000 professional, DOS , Windows XP etc
Applications Software - These are programs that help the users to perform task such as writing letters, drawing diagrams, performing accounting, editing programs e.g. Office Applications like MS Word, MS Excel, Sage accounting package etc Hardware - Are basic components of computers e.g. Printer, Screen (Monitor), Memories chips etc
Information - Refers to a processed data that is meaningful and useful Information
Processing - Is the production of data or raw facts into useful or meaningful form
Peripheral Devices - Are input devices, output devices or auxiliary storage devices connected to the computer externally
Many people are not familiar with the history of computers. But for those that have done Computers related courses life information Technology, Computer Science has the knowledge about the history of computers. In this blog you have come to the right place where you will learn all the basic you need about computers, starting with definition of computers. Who invented the Computers and what were the first Computer Like. Our First Article is about computer history, if you have no information about the computer history you need not to pay a lecture to teach, all that you can get here for free, with only one condition that you will come back for more updates on this blog.
Computer are grouped according to their generations starting from 1. First Computer Generation 2. Second Computer Generation 3. Third Computer Generation 4. Fourth Computer Generation 5. Fifth Computer Generation To learn exhaustively about computer history just click on: Chapter 1. History of Computers
