INPUT/OUTPUT DEVICES
by sumit kumar
Introduction of computer system
A computer system is an asset which include few tangiable assets as peripherals, procesing device, memory etc. they can either be divided in system panels or as entities involved to make computer system possible. Here are some terms as system panel or system entities of the computer system.
What is input
Input is an anatomy of the computers which is kindly referred as the data or information which is used to take as imput by the computer system so that a certain processing may take place to let you have a definite output.
There are many more electronic devices used to give input to the computer system. Here are some examples....
- MOUSE
- KEYBOARD
- SCANNER
- TRACK BALL
- JOYSTICK
- LIGHT PEN
- OCR
- MICRO PHONE
- BAR CODE READER
- MICR
INPUT DEVICES
This is kind of computer devices what are used to provide an input to the computer system by a user. These devices what are used to provide input or output are called peripherals. There is number of Input Devices like keyboard, Mouse, Track Ball, Light Pen, Web Cam etc. In these the keyboard and the mouse are the most comman input devices used frequently.
KEYBOARD
It is an input device what is used to give input on command or text basis compare to other input devices. A keyboard contains number of keys like alphabetical keys, Numeric keys, Functional keys, special keys and multimedia keys. Multimedia keys come only in multimedia keyboard.
- Alphabetical Keys-A to Z or a to z.
- Numeric Keys- 0 to 9.
- Functional Keys- F1, F2, F3 to F12.
- Special Keys- Shift, Ctrl, Alt, Enter, Esc etc.
- Arrow Movement Keys- Up, down, Left, Right.
- Multimedia Keys- play, pause, Next previous etc ( Only in Multimedia Keyboards)
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MOUSE
It is an input device what is used to give an input by pointing a command. It is a device that is used control the computer; kind of Input device. There two kinds of mouse 1) Machenical Mouse 2) Optical Mouse but now-a-days only optical mouse are being used every where in the personal computer.
The characteristics of mouse are:
- A cable connects the mouse to the computer. When the mouse is moved on a pad, the cursor moves on the screen.
- A cursor is a small symbol displayeed on the computer screen (normally a diagonal arrow that used as a pointer) that shows you what the mouse is referencing on the screen.
It points & Click with two Buttons and wheel. Normally Left Click for select/run and right click generate Menu.
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Joystick is a kind of input device what is used to give an input ot the computer system. That is mostly used in Game applications. As its name implies a stick to play a game that will let you feel joy. In this you use your thumb to press buttons of joystick handing the stick of the input device. There is a spherical ball in a socket at the bottom.
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Scanner are used to enter information directly into the computer memory. This device works like a Xerox machine. The scanner converts any type of printed or written information including photographs into digital pulses, which can be manipulated by the comuter. It is used to capture images off paper and convert it into drive Bar code reader is also a special type of scanner. Scanners can also use a special kind of technology called Optical Character Recognition (OCR) to read text from paper and save it s an editable document file.
It is a camera device used to take or record pictures, can be used as an input device. It is used mostly in chatting applications to do video chats and even you can take snapshots or record a video live offline. This uses VGA resolution.
WHAT IS OUTPUT
Output is a later process of Input & Processing which let a user know his/her output information via different output medium. Whenever you give instructions to computer to process a data then after processing what result you see that is known as output. There are many more output Devices give result either in hard or soft form. The devices which are used to display the data to the user either in the form of hard copy or soft copy are called output devices.
The example of output devices are as follows...
- MONITOR
- PRINTER
- PROJECTOR
- PLOTTER
- SPEAKER
This is an Output device. There are two types of the soft Output device; Audio Output device for eg visual Output devices. VDU is a visual soft output devices and used for the getting soft visual output onn screen. It measured diagonally from one corner of the screen to the opposite corner. VDU can be categorized into two types on the basis of technology the first one is CRT and second is LCD. The details are as under:
- CRT (Cathode Ray Tube) : This is television-like screen where the results of a computer's tasks are displayed. In this technology Cathode Ray falls on florescence screen and by deflecting rays make picture. There are two types of CRTs:
- Monochrome : Also called black and white.
- Color : It has three different phosphors which emit red, green, and blue light respectively and to the RGB color picture appears in colored view.
- LCD (Liquid Cristal Display) : This VDU is thin; flat and having light modulating technology. It is of two types:
- TFT (Thin Film Transistor) : It is a variant of LCD and makes matrix but not self lighting.
- LED (Light Emitting Diode) : It is self back light emitting technology; picture quality is better.
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SPEAKERS
Speakers are also kind of output devices which is used to play a sound as output. It is used multimedia applications to play or listen to sound or music. Speakers are attached to the computer via certain wire with sound out jack port. Generally jack size of speaker wire is of 3.5 mm which is most common is all sound devices and now-a-days the smartphone or multimedia phones are also coming with this feature.
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PRINTER
A printer is an Output device that prints text documents, images, spread sheet etc. as hard copy. Printer's quality is measured in dot per inch (DPI). The two most common types of printers are Impact Printer and Non-Impact.
Impact printer
This type of printers strike against the ink ribbon and make impression on the paper. There is a metallic or plastic head having pins (nine pin or 24 pin head in dot matrix) or symbol and characters (in daisy wheel printer). These printers are noisy, slow, cheap and poor quality Output.
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Dot Matrix
A dot matrix printer creates characters by striking pins against ink ribbons. Each pin makes a dot and combinations of dots from characters and illustrations. This is much like a typewriter. Each character is made from a matrix of dots. Today, dot matrix printers are not used by many people anymore. They are still in use where forms (with multiple copies) need to be filled out.
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NON- IMPACT PRINTER
In this technology there is no any hammer to strike against ribbon. This is latest technology. The two main types of non impact printers are;
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Inkjet Printer
In this technology 'lonized Ink" spraying through magnetic plates on the sheet and making the symbol, image or documents. These printers produce high quality printings. It can print up to 300 DPI or more.
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CPU (Central Processing Unit)
Processing Device means calculation comparisons and decisions. The processing devices are Central Processing Unit (CPU); also called Microprocessor is a small chip in Computers which receive Input and provide Output. It is composed of silicon and contains millions of transistors for e.g. Pentium, Dual core, Core 2 Duo, Core i3,i5,i7 etc. It consist ALU, CU and MU (Memory Unit).
Arithmetic Logic Unit (ALU)
This very section of Central Processing Unit executes all the arithmetical and logical operation. This is the major component of the central processing unit. It does all the operation as the direction whether arithmetical or logical upon the data or information and send that to memory unit from there the control unit sends back the result to the output media through buses as the user direction instruction.
CONTROL UNIT
Decode instructions and determines which is next to be executed. Control unit is a Part of the processor that is in-charge and it directs the computer system to execute stored program instructions. It communicates with other parts of the hardware.
MEMORY UNIT
In this unit, the data are stored during the processing. Its speed is faster access than memory. Formally we call this Registers too. In this unit, the data are stored during the processing. Its speed is faster access than memory.
PROCESSOR SPEED
Processor is the major component of the computer system which does processing of the data and information as per the user instruction. Performance of the computer system depends on the processor's capability. It can process an instruction directed by a user in seconds. It does processing far quicker than human beings. It can process instructions more than one million in a second that is formally called or known as million instructions per second (MIPS).
The processor speed depends upon the bit executed by the processor. It comes in various kind like 8- bit processor, 32- bit processor and 64- bit processor. It depends what processor you are using.
- The 8- bit processor executes 8 but at a time in the form binary number system like (10010111)2.
- The 8- bit processor executes 16 bits at a time in the form of binary number system. This kind of processor is faster than 8- bit processor and used much at its time.
- The 32- bit processor executes 32 bits at a time means twice faster than 16- bit processor. It is used mostly in all the personal computers now-a-days, is much sufficient at speed.
- 64- bit processor executes 64 bits at a time, is used at servers or mini computers to handle or process bulk data.
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