Computer System (IPO)

·         Computer System

-          Computer is an advanced electronic device which takes raw data as input then processes these data as proven instruction then gives output and stores it for future use. It is a data processing machine, which can process any kind of numerical and nonnumeric operation under the control of sequential instructions called program. In other word any electronic machine that can perform their work 'IPO' cycle is know as computer.

IPO CYCLE:

INPUT                                                   PROCESS                                                                     OUTPUT

(Raw data)                                          (Unseen)                                                                             (Result)

(Input Device)                            (Processing device)                                                              (Output Device)

1)      INPUT:

-          Input is the raw information. It is the collection of facts or figures or both. It is done through input devices. eg. through mouse, keyboard.

2)      PORCESS:

-          Process is the manipulation of data as per give instruction. It is done through Central Processing Unit

3)      OUTPUT:

-          Output is the processed data. It is also called result and displayed though Output device like monitor , printer.

modem

·         WHAT IS MODEM? WHERE IS IT MOSTLY USED?

-          Modem stands for modulator and demodulator. It is an electrical device that allows a computer to transmit information over a telephone line. The modem translates the digital signal to analog and analog to digital signals. When transmitting, the modem modulates the digital data into an analog signal on telephone line. When receiving the modem performs the reverse process. It is mostly used in internet and telephone communication.

On the basis of printing method:

On the basis of printing method:

i)                    Character printer:

character printer prints only one character at a time. It is very much slower printer used to print low volume of output. It prints 100 to 300 characters per second. Example Dot Matrix, Daisy wheel etc.

ii)                   Line Printer: Line printer prints only one line at a time. It is faster than character printer and sued to produce large volume of output. It produces 200 to 2000 lines per minute. E.g. chain Printers, Band printer, Drum Printer etc.

iii)                 Page Printer: the printer which prints entire page at a time is called page printer. It is faster than line printer and produces high quality outputs. It can print 8 to 10 page per minute. E.g. Laser printer, ink jet printer thermal printer etc.

·         DIFFERENCE BETWEEN IMPACT AND NONIMPACT PRINTER.

Impact Printer	Non-Impact Printer
1)      Impact printer uses head and pins to print information.	Non impact uses thermal chemical and techniques.
2)      Impact printer is nosier.	They are not nosier.
3)      Impact printer produces multiple copies	They produce single copy.
4)      Impact Printer is cheaper.	Nonimpact printer is expensive.
5)      They are slower.	They are faster.
6)      It produces lower quality output.	It produces high quality output.
7)      It is mostly used in small organization.	It is used in large organization.
8)      Example: Dot Matrix, Line printer, Daisy wheel etc.	E.g. laser printer, thermal printer , ink jet printer etc.

Non impact printer:

Non impact printer:

 non impact printer uses thermal, chemical or optical techniques to print information. It is faster and produces high quality output than impact printer. But it produces single copy of text. Example of nonimpact printer is loser printer, ink jet printer, and thermal printer. It does not produce any noise while printing.

Merit:

a)      Printing quality of test and image is higher.

b)      It is faster than impact printer.

c)       It can be used in large organization

Demerit:

a)      It is expensive.

b)      It produces single copy of text.

c)       It is expensive to use in small organization.

Types of Printer

 

On the Basis of printing method                                                                      On the Basis of printing technology

Character Printer                Line Printer          Page printer         Impact Printer                               Nonimpact Printer

a)      On the basis of technology:

On the basis of technology printer can be classified into two types.

i)        Impact

ii)      Non impact

i)        Impact Printer: it uses heads or pins to strike against a ribbon or paper to print the text and information. It produces noise at the time of printing. Hence it is know of noisy printer. It printing quality of impact printer is not so good than nonimpact printer. Usually impact printer is slower than nonimpact printer. It produces only one copy at a time.

Merit:

a)      Impact printer can produce multiple copy of text.

b)      Impact printer is cheaper.

c)       Use in small organization.

Demerit:

a)      Printing quality is lower than nonimpact printer.

b)      It is nosier than nonimpact printer.

c)       It cannot be used tin large organization.

d)      It is slower than nonimpact printer.

Printer

1)      Printer:

Printer is a common output device that produces the human readable output. Printed output produced by printer is usually referred as hard copy output. They provide information in a permanent readable form. They produce printed output of result programs and data.