Computer Classification

Computer classification use to identify the correct computer for the required task.in here we are learning computer categorization under 3 reasons

1. By the operating principals
2. By the aim of the application
3. By the size and speed

By the operating principals
In this categorization we consider the current signals using in side the computer There are two signal types we consider

• Analogue signal

a signal that represent a value within a range and increase decrease over a time continuously.

• Digital signal

a signal that represent a value using pulses within an same interval (Frequency)and includes only two states (1/0)(On/Off)
Digital computers
computers uses digital signals for process data ,it uses a counter to count the signal and calculate the vale due to the signal pattern
Analogue computers
computers uses analogue signals and it measures the signal for indicated value.
Hybrid computers
the computers uses analog and digital both signals and they have both signal types advantages.
According to the aim of the application
Special function Computers
This computers that design for only specific task (Function). it includes the performance and devices that only facilitate for the given task(Function).
Eg: Automated tailor machine,Medical scanner machines
General purpose computers
this computers are designed for common general applications of the society.they support for install applications programming games ,word processing etc.
Size and the speed of the computer
in here we consider about the size and the performance of the computer to categorizing.

• Super computer
• Mainframe computer
• Mini computer
• Micro computer

Super Computer
Computers that has high performance than nonequivalent to the other category we explains as super computers. they are uneuqelent by speed memory accuracy and other performances
Main Frame computers
These computers are only second for super computers under performances.
Mini Computers
These computers has more performance than micro computers. this computers
Micro Computers
Named as Personal computer because one person at a time use this computer, and Desktop computer because it can arrange in a desk. this computer is doing task one after the other (Serial) and have less performance for supporting for only single user
Laptop(notebook)
a computer that can keep on your lap, this belongs to microcomputer category but this is portable . you can carry it when traveling.
tablet
like a notepad ,you can easily handle it lie a note pad
palm pilot
small computer that can keep on your palm
other types of computers
Network computer
a computer that link in to a network(LAN) can explain as network computer and can name as workstation also.if it is controlled by a server in client server environment it also named as client.
computer platform
computers are manufactured by different companies and they uses different processor architectures in its processing and handling instructions. so different plat form uses different type of instructions.
Eg:
Apple,Intel,
computer platform not only depend by the processor architecture ,but also with operating system . we ll discuss later.

Compuetr System

When learning about a computer system, we learn about all the components that are used when using computers.
For learning purpose we classify computer system into four categories

• Hardware : Physical components of the computer
• 
• Software: the instructions that use to control the computer 
• 
• Liveware : the people who are working with the computer
• 
• Firmware : manufactured permanent instruction set of the computer
• 

Hardware
Named as hardware because in hardware we discuss about tangible(Physical devices ,machinery equipments) of the computer.
in here we categorize hardware again into four main categories.

• Input Hardware
• Output Hardware
• Processing Hardware
• Storage Hardware

Input Hardware
the hardware devices that use to input data into the computer can explain as input hardware
We can categorize them again under the type of input they get

• Character input device -Keyboard,micr

vb  key board uses a cursor to locate the next carater in the screen and when pressing the key it prints the key at the next cursor location . some keys are uses for control instructions.To learn about Keyboard go to keyboard guide.

• Pointing Device-Mouse

Mouse uses to show select any place of the screen. it uses a pointer at the screen to show current position. the pointer moves according to the movements when user moves the mouse.
trackball
Track stick
Touch pad
light pen

• Graphic input devices

scanner
Digital camera

• Voice input devices

microphone

• video input devices

web camera

• card readers

magmatic strip card reader

• code reader

Bar code reader

• Mark reader

OMR

• motion sensors

Data glow

• biometrics

finger print reader
Output devices
the devices that use to output Indicate something to user can explain as output devices.they also categorize under many reasons mainly we can categorize under tow categorizations.

• soft copy output devices
• Hard copy output devices

soft copy output devices
this out put devices gives non tangible out put to the user . because we name as soft copy output device

• monitor(screen,Visual Display unit)
• Speakers(sound)

Monitor
it users mostly power supply from outside of the system unit it need power supply and video signal cable . by the technology we can categorize the monitors.

• CRT
• LCD
• plasma
• LED
• SED

projector
Sound

• sound blasters
• Sub woofers

Hard copy output devices

• printer

impact

• drum
• daisy wheel
• ribbon
• dot matrix

non impact

• inkjet
• laser jet
• thermal

plotter

ICT

IT (Information Technology)

ICT(Information and Communication Technology) is a very popular word these days. Before learning them we should consider What Why and How they affect to us
In the past we discussed two technologies named Computer Technology and Telecommunication technology

1. Computer Technology : Use to process Data , Store Data/Information,Retrieve Stored Data/Information
2. Telecommunication Technology : Use to send signal/message from on place to other place Remotely Eg: Radio,Television,telephone In here they discuss about data/Information sending(Transmission) and Data/information Receiving

Later using devices like the modem, the computers could (connect) communicate together within remote locations, then it enabled:

1. Information Technology including computer networks, Internet which facilitate transfer/Share data over two or many computers in remote locations in the world eg: E-mail, WWW, FTP
2. further IT(Information Technology) facilitate for other social communication methods like Chatting(IRC), newsgroups,Blogs,Walls including social networks over the internet .they facilitate them through other mobile devices like pdas, cell phones and portable PCS. then it describes as Information and communication Technology(ICT)

Introduction to computer

What is a Computer?

Very simple answer is a machine. To understand completely lets discuss from the very simple place

Machine

We can explain a machine as a device that makes work easier for humans

Machine has

1. Input :What we input to the machine
2. Processing :The process(task) happens inside the machine
3. Output :What we can get as output/result from the machine
4. Control : The machine is operated for humans purposes. Because Human should communicate with the machine to control it, Adjusters, leavers, buttons, keys, etc are use to control the machine.

If computer is a machine we could define
We can identify
computer is an electronic machine that input DATA ,PROCESS them according to the INSTRUCTIONS and returns INFORMATION as result.

1. What input to the computer : Data
2. What process happened in the computer : Compute
3. What outcome we can get from the computer :Information
4. How we control the computer :Instructions

Data: Fact(Value/Characteristic) or attribute about relevant to something.Data can be classified into:

1. Quantitative :Describe about Value(Quantity) eg:age,height
2. Qualitative :Describe About Quality Eg:Color,Gender

Data should have good qualities like

1. Accurate
2. Up to date(timely)
3. Relevant
4. Complete
5. Concise(well presented)
6. Clear
7. Useful(adapted to user requirements)
8. Accessible
9. Economical
10. Verifiable

Data can collect through measurement or storage/recordable device forms or in oral methods. Unprocessed data is know as ROW DATA.

(Processing) Compute: (Solving) Arithmetical and logical processing solution can be described as computing(Data Processing)
There are two data processing methods

1. Manual Data processing (Human Based)
2. Electronic Data processing (Machine Based)

Information:Useful things that we can obtain after processing data,The data also useful but in information the data has been formed to the recommended (required) manner.
Instructions:To control computer we use instructions. A set of instructions we can explain as computer program (Software,Application) .computer has the ability to execute (work according to) this instruction set.
Knowledge:The instruction set has been formed by understanding about a matter(problem)that we are solving . To create instructions to computer (Program) we need Knowledge.

What Computers Can Do?

As discussed Above

1. Input
2. Process
3. Output
4. Store
5. Retrieve
6. Communication and Control

  The purpose of using computers

Computer is programed by the human to solve any problem and it executes those programs when needed. Here the most important factor is the computer has some advantages when uses for data processing

Advantages

1. Speed : Computer is working by electronic signals. So it can execute instructions faster
2. Memory capacity: Computer have a huge memory capacity which can access faster in many formats like documents,pictures,sounds etc. and even instructions.
3. Accuracy: computer gets values up to more accurate decimal values within a small time period and the value is accurate out of a problem of data input
4. Diligence: the computers never been tired and reduce the accuracy due to sickness or tired . it can work for a long time period with same working quality.
5. Reliable: Computer stored data never change and it stores for along time period with proper storage medium.
6. Secure : We can protect our data and information by using passwords.
7. Versatile: computer can apply in various purposes in day-today activities
8. Multitasking: Computer can do multiple tasks at the same time
9. Automation: computer can execute a program without any other persons involvements.

Disadvantages

We have to keep in mind that the computer is a machine. So the computer only execute instructions and it does not have intelligence to think. So it has no:

1. Creativity
2. Favors
3. Sensitive Decisions
4. feelings

How We use the computer?

Computer is a device that was invented by Scientific and Engineering technology. They use it for calculations and logic processing. and then for drafting charts and graphs.
With calculating capability and storage capability in used by the business and accounting field.they use this computer for calculations and documentation purposes integrating the printing capability.
With documentation capabilities it comes to the education and offices for day-today activities. and then it is empowered with Multimedia(Audio,Video,Text,Graphics and Animation) then it comes to the entertainment field.They are used at homes for video audio movie games.
With the improvement of internet now it is using in communication and vast applications of electronic society like ICT.