What is a Printer

The Computer system needs to convert the document to a format, which is understandable by the printer for printing. The device drive of a printer helps convert a document to a format, which is understandable by the printer. The performance of a printer is determined by the parameters, Dots Per Inch (DIP) and And Pages Par Minute (PPM).
The DPI parameter of a printer, the better is the quality of the output generated. The PPM parameter of a printer represents the number of pages that are produce par minuter. Printers can by classified on the best of technology that they use to print the text and image:

• DOT MATRIX 
• LASER
• INKJET 

The Dot matrix Printer 

A dot matrix printer uses perforated sheets to print text. Dot matrix printers are impact printers as they print the text on a sheet, by striking a pin against the ribbon to produce its impression on the paper. Dot matrix printers are used to produce multipale copies of a print out, as the striking motion of the pins helps in making carbon copies of atext also ..

Shows a dot matrix printer.

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Basic Concept OF Operating System

An operating system is a set of instructions stored on a storage device such as hard disk, Compact Dist  Read Only Memory (CD ROM) or floppy disk . When you switch on a computer , the power on routing activates and a set of a power -on routine activities is performed . These power -on routine
activities verify the devices attached to the CPU , such as keyboard, hard disk, floppy disk. CD ROM and printers for their proper functioning. The instructions for these power-on routine activities are stored in the
Read Only Memory is permanent in nature and stores the data even when the power is switched off.
However, ROM stores only few kilobytes of  instructions due to its finite size . AS a result , the power -on
routine activities are stored permanently in the hard disk as operating system, and are transformed from the hard disk into the Random Accese Memory (RAM) on booting the computer system 

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