COMPUTER: -----------
Computer is an Electronic device which is used to compute. It is basically used for process the input data given by a user. The character by character meaning of computer is given below………
C:- Common
O:- Operating
M:- Machine
P:- Particularly
U:- Uses for
T:- Training
E:- Entertainment/Education and
R:-Research
Basic functions of a computer:--
Computer is used in a lot of areas and it performs a lot of works but the basic working of a computer is same for all.
It always receives input (Raw data) from user and after processing according to the user’s instructions it provides output(useful information).the whole processing is given below------
PARTS OF A COMPUTER
A) Hardware
B) Software
A) Hardware:-
All the devices of a computer that can be physically accessed by a user or those devices that we can touch are called hardware. It can be divided in following units-- --------------
1) Input devices:-
keyboard, mouse, joystick etc.
2) Output devices:-
Monitor and Printer.
3) Processing devices:-
Processor, Motherboard
4) Storage devices:-
Hard disk, RAM.
SOFTWARE:-
Software is a collection of interrelated programs for any specific task. It provides us a platform to interact with the hardware of computer system. Software cannot be touched.
SYSTEM SOFTWARE:-
It is a set of programs used to interact between user and computer hardware. System software is the basic s/w that is necessary to use to computer. Without system software, we cannot use hardware. We can divide system software into four parts.
1).Operating system (OS)
2). Language translator
3). Device driver
4). Utility programs
1).Operating system (OS):-
Operating system is a system s/w works as an intermediary between the user and hardware of computer system. It exists on the top layer of h/w and provides us an interface or virtual machine which is more convenient to use than a bare h/w machine.
FUNCTIONS OF AN OS:--
A). Memory management
B). Process management
C). File management
D). Security
E). Command Interpretation
A). Memory Management:-
The memory management module of an operating system takes care of data transfer between both primary and secondary memory of a computer system.
It is responsible for managing both memories primary and secondary in the sense that primary memory will be used only for current works and secondary memory will always be used for saved work.
B). PROCESS MANAGEMENT:-
Process means—a program in execution, so the process management module of an operating system takes care of execution, and termination of different types of process in computer system.
As we know all programs are installed in secondary storage but when we call any program, it is loaded into RAM as a process by OS.
C). File management:-
The file management module of an OS takes
Care of all file related activities like creating file, editing file, deleting, sorting, merging etc.
As we know all files that we have not saved are loaded into RAM but after giving a command to save a file it will saved in secondary storage.
D) Security: -
Each Operating system has in build feature of providing security from unauthorized access. For security, it provides a user name and password to login in computer. So a user with no username and password cannot access the system.
E) Command Interpretation:-
Each operating system has its own interface for the users either it will be user friendly interface or a more difficult interface. So there are two main interfaces that usually all OS provides…………………..
1) GUI--- Graphical User Interface
2) CLI ----Command Line Interface
2).Language translators:-
Language translators are system software used to translate the instructions given in user language into machine language and then translating the output given in machine language into user language.
There are three types of language translators-
(1) Assembler
(2) Compiler
(3) Interpreter
Languages used by a computer:--
Computer uses different types of languages, some of them are given below…………….
A) Machine language
B) Assembly language
C) High – level language
A) MACHINE LANGUAGE:-
Machine language is a language that can be understood only by a machine.
A machine can only understand ‘1’ and ‘0’ (binary language), but it is very difficult to understand by us.
B) ASSEMBLY LANGUAGE:-
Assembly language was created to remove the complications of binary language. It was the first computer language created by human. Some characteristics are given below….
1) Basic language of computer
2) Machine dependent language (every instruction can be run only in that P.C for which it is written.)
C) HIGH LEVEL LANGUAGE:
BASIC, PASCAL, C, C++, JAVA, FORTRAN, HTML are the high-level languages used now a days to instruct the PC. Some basic characteristics are given below…..
(a) Machine independent language.
(b) Very easy to learn.
(c) Very easy to mange.
3) Device drivers----
Device drivers are system software used for a specific hardware to tell the operating system about the working of that particular hardware.
Each hardware should have a device driver program installed into the operating system.
4) Utility programs:------
Utility programs are system software that assist a user in system maintenance tasks like scanning system for viruses, data recovery, backup data, disk formatting etc.
Example: - Antivirus, backup s/w, recovery tools, disk formatting s/w etc.
APPLICATION S/W: -----
Application s/w is system S/w that is used to done some specific task such as:-image editing, designing, webpage, designing, listening music etc.
Support system S/w as operating system.
Example: - Microsoft office, Photoshop, Corel, Mp3 player, video player, Flash, Dreamweaver, Sound forge , 3Dmax etc…
Icon:-The representation of Programs through a small image is called Icon.
Desk Top:-It is the palaces which appears after the o/s fully lode into RAM. It contain ‘start menu’-A way to open all programme.
Task Bar: - It is a place like a blue line below the desktop is shows the entire program currently running on system.
My Computer: - Exist in desktop. To open all files, directories devise in a computer.
My Documents: - default places for save documents or files.
Recycle bin :-Place where are deleted files are exist when we delete a file from computer it automatically shifted into recycle bin. It is fully deleted from system when we delete files from recycle-bin.
PROCESSOR:-It is a brain of a computer. It is responsible for all processing on given data. It controls all other H/w and S/w application through control unit and process according to given instruction and sends it to Output devices.
STORAGE UNIT:-That are used to storage a bit of information (data) called storage devices.
Primary storage:-Temporary storage DATA is saved for a little time.
RAM:-(random access memory) It is a part of Primary .The current Process are running into a Ram. If we do not save our work than it will lost when the system turn off.
Two types of Ram:-
(1)Static Ram
(2)Dynamic Ram
ROM:-It is part of Primary storage that is used only to read the data or information stored in it, we can’t change or over write these saved data
There Types of Rom:-
(1)P-Rom- Programmable Read only memory.
(2)Ep-Rom-Erasable Programmable Read only memory.
(3)EEp-Rom-Electrically Erasable Programmable Read only memory.
CACHE Memory:-The part of Primary storage machine of using static Ram Internal memory of Micro Processor. It is also called Duffer memory. Processor Process all the tasks into it cache memory. Speed of Cache memory is very fast.
Secondary Storage:- It is Piermont storage of a P.c. We can call it Non-volatile memory. It mean we save any file in this storage. It will not lose after the system turn off.
PHERI PHERALS :-
( 1) Mother board
(2)CD-ROM/CD
(3)FLOPPY drive
(4)SMPS(switch mode power supply)
Mother Board: - Main boad, all input, output, processing storage devices are connected to Mother Board. It provides a separate interface for all type of devices.
CLASSIFICATION OF COMPUTER
(1)PERSONAL COMPUTER:-A small, single user computer based on a micro-processer.
(2)Workstation:-A power full, single user computer. It is like P.C but it has more powerful micro processor and higher quality monitor.
(3)Minicomputer: - A multi-user computer capable of supporting form 10 to hundred of user simultaneously.
(4)Mini frame: - A powerful multi-user computer capable of supporting many hundreds or thousands of users simultaneously. Popular mainframe series are MEDIA, Sperry, DEC, IBM, HP
HCL etc
(5)SUPERCOMPUTER: - An extremely fast computer that can perform hundred of millions of instructions per second. These are a amongst the fastest machines in terms of processing speed and use multiprocessing techniques, where a number of processors are used to solve a problem. Supercomputer is mainly being used for weather forecasting, computational fluid dynamics, remote sensing, image processing, bio-medical applications etc.
KEYBOARD: - Keyboard is a typewriter-like device, which contains keys of feed information into the computer. In general, keyboard is available in two models. The standard keyboard With 83-84 keys; and enhanced keyboard with 104keys or more. The keys of a standard computer keyboard along with their function are described below:
*Typewriter keys:-These are normal keys to the keyboard. They include letters, numbers, and punctuation symbols.
*Function keys:-These are, labeled F1toF12, are located at the top end of the keyboard. The functions they perform depend on the software that you use.
*Cursor Control keys:-These keys marked as are called the Left, Right, Up and Down Arrow keys, respectively.
Printer:-A device that prints image (numbers, alphabets, graphs, etc.) on paper is know as printers. After creating a document on the computer, you can send it to the printer for printing its hard-copy which is generally called a printout. The speed of a printer is rated either by pages per minute (ppm) or by characters per second (cps).you can take printout in full colors in black color only.
CLASSIFICATION OF Printer
*Dot Matrix printer:-This type of printer makes use of pins. The pins strike an ink ribbon. As each pin hits the ink ribbon, a dot appears on the paper, and combinations of dots form characters and illustrations. A dot matrix printer can print 1to 8 page in one minute. Use of dot-matrix printer is now limited to printing invoices and bills.
*Inkjet printer:- This type of printer sprays in a sheet of pager. Ink-jet printers produce high-quality text and graphics. An inkjet can print 4 to 6 pages in one minute. Due to its low price and affordability, the inkjet printer is popular in home specially among kids.
*Laser printer: - This type of printer uses fine powder ink called toner. Laser printer uses the same technology as photocopy machines. They produce high quality text and graphics prints. The laser printer is quite popular in corporate world and printing houses.
MONITOR
Monitor of a PC works like a television screen. It displays text characters and graphics in colors or in shades of grey.
CLASSIFICATION OF MONITOR
*Dot Pitch:-The dot pitch is a standard to measure how close together the pixels or dots to create an image on the monitor. The finer the dot pitch, the better image quality you will have. The dot pitch is entirely depends upon the type of computer.
*Resolution and Refresh Rate: - The resolution and refresh rate are two combined factors and depend upon each other. They hand-in-hand to produce a clean image, and they both depend on the bandwidth available form your video card.
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