COMPUTERWHAT IS A COMPUTER ?A COMPUTER IS AN ELECTRONIC MACHINE WHICH CALCULATES EXTREMELY FAST, FASTER THAN A CONVENTIONAL CALCULATOR. A COMPUTER WORKS UNDER A SET OF RULES WHICH IT IS DESIGNED. BEING A MACHINE IT WIL NOT PERFORM INDEPENDENTLY OR CREATIVELY.

A COMPUTER SYSTEM PERFORMS TWO TYPES OF PROCESSING. THEY ARE:-A) NUMERICB)NON-NUMERIC

NUMERIC PROCESSING :-NUMERIC PROCESSING INCLUDES ADDITION,SUBSTRACTION, MULTIPLICATION AND DIVISION

NON-NUMERIC PROCESSING:-

i)TEXT PROCESSING :- WHAT EVER YOU TYPED IN IS A DATA ENTRY FOR TEXT PROCESSING WHICH COMPUTER PERFORMS.

II)LOGICAL PROCESSING:-WE CAN MAKE A COMPUTER PERFORM SOME TYPE OF PROCESSING WHEN WE FEED DATA OR INSTRUCTIONS WHICH FORCES A COMPUTER TO CHOOSE FROM TWO ALTERNATIVES.

FOR EG : - YES OR NO (Y/N), TRUE OR FALSE

THE ACTIVITIES OF A COMPUTER SYSTEMTO MAKE A COMPUTER WORKS, YOU HAVE TO FEED TWO THINGS:-

A)INSTRUCTIONS ON WHAT THE COMPUTER SHOULD DO.

B)DATA ON WHICH THE COMPUTER SHOULD CARRY OUT YOUR ORDERS.

THE THREE PROCESSES WHICH A COMPUTER WORKS THROUGH ARE:-

A) INPUTB) PROCESSING C) OUTPUT

THE PROCESS OF FEEDING DATA AND INSTRUCTIONS IS CALLED INPUT.

Eg:-KEYBOARD, MOUSE, JOYSTICK, SCANNER, DIGITIZER

WHEN A COMPUTER WORKS ON THE DATA IS CALLED PROCESSING.

Eg:-CENTRAL PROCESSING UNIT

GIVING THE RESULTS AFTER PROCESSING IS CALLED OUTPUT.

Eg:- MONITOR, PRINTER, PLOTTER, ETC.

INPUTPROCESSINGOUTPUTSTORAGESOFT COPY/VDUHARD COPY/PRN

DATA :-

IT REPRESENTS CHARACTERS, WORDS, SENTENCES, WITH OR WITHOUT RELATIONSHIP AMONG THEM.

FOR EG :- HE, LIVING, DELHI, 1200

MEANINGFUL DATA :- A SET OF DATA ORGANISED TO FORM A MEANING

FOR EG:- HE IS LIVING AT DELHI HAS RS.1200.

HARDWARE

ANY PHYSICAL COMPONENT OF A COMPUTER SYSTEM IS CALLED HARDWARE.

HARD WARE IS THE ONE WHICH WE CAN SEE AND FEEL.

Eg:- KEYBOARD, MOUSE, CPU, MONITOR ETC

SOFTWARE :-

THE INSTRUCTIONS WE FEED INTO THE COMPUTER TO PERFORM A SPECIFIC TASK IS CALLED AS SOFTWARE.

SOFTWARE IS THE ONE WHICH WE CANNOT SEE.

EG:-DOS, WINDOWS

THERE ARE TWO TYPES OF SOFTWARES :-

A)SYSTEM SOFTWARE :-WHICH INCLUDES THE OPERATING SYSTEM AND UTILITY PROGRAMS

OPERATING SYSTEM IS THE ONE WHICH RUNS THE COMPUTER.

UTILITY PROGRAM IS THE ONE WHICH HELPS US TO CARRY OUT SPECIAL TASKS SUCH AS EDIT, COPY, PRINT ETC

APPLICATION SOFTWARE :-

APPLICATION SOFTWARE COVERS GROUP OF PROGRAMS WHICH ARE USED TO RUN SPECIFIC APPLICATIONS.

EG :- MICROSOFT WORD, EXCEL, POWER POINT, ADOBE PHOTOSHOP. ETC..

BASIC ELECTRONICSPOWER SUPPLY :-THERE ARE TWO TYPES OF POWER SUPPLY

A)LINEARB)SMPS

LINEAR :-THIS IS NOT ADVISABLE AS IT GRADUALLY INCREASES AND EASY TO DAMAGE THE SYSTEM.

SMPS (SWITCH MODE POWER SUPPLY) :- THIS IS NORMALLY USED NOW A DAYS AS IT GIVES STEADY SUPPLY TO THE SYSTEMS.

SWITCH MODE POWER SUPPLYAFTER SWITCH ON, THE SMPS GETS 230V AND IT GENERATES FIVE TYPES OF VOLTAGES. THEY ARE:-

+5v, -5v, +12v, -12v AND PG SIGNAL OF +12v

PG SIGNAL IS THE HIGH ACTIVE SIGNAL WHICH DEVELOPES ONLY FOR A DURATION OF 0.01 SECONDS.

+5 AND 5v ARE USED BY THE PROCESSOR TO RUN VARIOUS LOGICS

+12V, AND 12V USED FOR VARIOUS PERIPHERALS.

TYPES OF RAM AVAILABLE :-

DRAM - DYNAMIC RANDOM ACCESS MEMORY

SRAM - STATIC RANDOM ACCESS MEMORY

DIMM - DUAL INLANE MEMORY MODULE

SIMM - SINGLE INLANE MEMORY MODULE

0

ROM (READ ONLY MEMORY)

THIS IS A PERMANENT STORAGE. ROM CONTAINS PROGRAMS LOADED INTO IT AND CONTAIN STARTING INSTRUCTIONS FOR COMPUTERS. ONE SUCH INSTRUCTIONS PERFORMS POST (POWER ON SELF TEST).BIOS IS ONE TYPE OF ROM. IT CONTAINS EPROM. EPROM (ERASABLE PROGRAMMABLE READ ONLY MEMORY.

BIOS BASIC INPUT OUTPUT CONTROL SYSTEMS.

MINIMUM MEMORY REQUIRED FOR :-

MONITOR -64 KB

OPERATING SYSTEM-640KB

BIOS-126KB

DATA STORAGE DEVICESHARD DISK

FLOPPY DISK

CD-ROM

TAPE DRIVE

COMMUNICATING WITH COMPUTERCOMPUTER IS AN ELECTRONIC DEVICE, THUS IT CANNOT UNDERSTAND ANY SPEAKING LANGUGE. IT CAN ONLY UNDERSTAND MACHINE LANGUAGES. AND THIS LANGUAGE IS BASED ON A PRINCIPLE OF ON, OFF i.e, CONCEPT OF TWO STATES.

EACH STATE IS REPRESENTED SYMBOLICALLY EITHER BY ONE OR ZERO. THE PRESENCE OF AN ELECTRONIC PULSE IS ONE AND ABSENCE IS ZERO

BINARY LANGUAGETHE ENTIRE COMPUTER VOCABULARY IS BASED ON THE PRINCIPLE OF ZERO AND ONE AND THIS IS KNOWN AS BINARY LANGUAGE.

BINARY LANGUAGE HAS ONLY TWO CHARACTERS, ZERO AND ONE.

EACH CHARACTER IS KNOWN AS A BIT (BINARY DIGIT)

EIGHT BITS FORM ONE BYTE

A BIT IS THE SMALLEST CHARACTER THAT A COMPUTER RECOGNISES AND BYTE IS THE SMALLEST STORAGE SPACE USED BY A COMPUTER TO STORE A BIT.

ARRANGEMENT OF BITS INTO WORDS IS KNOWN AS A BIT PATTERN

BIT PATTERN

THERE ARE TWO BIT PATTERNS IN A COMPUTER

ASCII (AMERICAN STANDARD CODE FOR INFORMATION INTERCHANGE)

EBCDIC (EXTENDED BINARY CODED DECIMAL INTERCHANGE CODE).

LETTERSEBCDISASCII

A1100000101000001

B1100001001000010

C1100001101000011

D1100010001000100

E1100010101000101

F1100011001000110

G1100011101000111

..AND SO ON