computer classification of digital computers characteristics of computer objectives of computers functions of computers secondary storage devices input devices output devices programming languages operating system e-mail applications of computer computer security

1. FUNDAMENTALS OF
INFORMATION
TECHNOLOGY

2. COMPUTER
• A COMPUTER IS AN ELECTRONIC DEVICE THAT ACCEPTS RAW
DATA, PROCESSES IT ACCORDING TO A SET OF
INSTRUCTIONS AND REQUIRED TO PRODUCE THE DESIRED
RESULT.
• THE SET OF INSTRUCTIONS IS CALLED PROGRAM AND CAN
BE WRITTEN USING ARTIFICIAL LANGUAGES LIKE
• BASIC, FORTRAN, C, C++, JAVA ETC.
• A COMPUTER CONSISTS OF TWO MAIN COMPONENTS:
HARDWARE AND SOFTWARE

3. CLASSIFICATION OF DIGITAL
COMPUTER
• COMPUTERS CAN BE CLASSIFIED BASED UPON THEIR MODE
OF USE AS
COMPUTER FOR SIMPLE USE
COMPUTERS FOR ORGANIZATIONAL USE
• SIMPLE COMPUTERS ARE ALSO CALLED MICRO COMPUTERS
AND INCLUDE
• PERSONAL COMPUTERS ,
• LAPTOPS,
• PDA (PERSONAL DIGITAL ASSISTANT),
• WORKSTATIONS ETC.

4. PERSONAL COMPUTERS
• POPULARLY CALLED PCS.
• THEY ARE FOUND ALMOST EVERY WHERE NOWADAYS.
• THEY COST LESS AND ARE SUITABLE FOR HOUSE AND
INDIVIDUAL USE.
• THEY COMPRISE OF A MONITOR, A KEYBOARD, CPU WITH
FLOPPY, CD AND HARD DISKS AND A MOUSE AT THE
SIMPLEST.
• THEY RUN SOFTWARE LIKE WORD PROCESSORS, EXCEL,
COMPILERS, IMAGE VIEWERS, GAMES, INTERNET BESIDES
THE OPERATING SYSTEM

5. LAPTOPS
• THEY ARE EQUIVALENT TO PCS IN THEIR FUNCTIONALITY.
BUT, VERY SMALL IN SIZE COMPARED TO PCS.
• THEY ARE PORTABLE, IN THE SENSE, YOU CAN CARRY
THEM WHEREVER YOU TRAVEL. THEY RUN ON BATTERY.
• AS LONG AS THE BATTERY CAN SUPPLY POWER, THE
LAPTOPS FUNCTION.
• HERE, MONITOR, KEYBOARD, MOUSE, STORAGE
DEVICES ARE INTEGRATED AS ONE DEVICE

6. PDA(PERSONAL DIGITAL
ASSITANT)
• THEY ARE SMALL COMPUTERS WHICH CAN BE HELD IN
HANDS.
• THEY ARE USED TO BROWSE INTERNET AND
RECEIVE/SEND SHORT MESSAGES.
• THEY ARE ALSO USED TO STORE INFORMATION WHICH
CAN THEN BE TRANSFERRED TO PCS IN LEISURE.
• NOWADAYS THEY ARE USED TO WORK WITH SMART
CARDS WHICH HAVE USER INFORMATION LIKE NAME,
THEIR LOAN OR CROP DETAILS.

7. WORK STATION
• THEY ARE HIGH END PCS.
• THEY CONTAIN MORE MEMORY AND HIGH SPEED
PROCESSOR COMPARED TO PCS.
• THEY HOST SOFTWARE REQUIRING MORE RESOURCE.
• THEY ARE USED IN BUSINESS BUT BY A SINGLE USER.
• TYPICAL WORK DONE ON WORKSTATIONS INCLUDES VIDE
EDITING, ANIMATION, DRAFTING OF AN ARCHITECTURAL
DESIGN, ANIMATION ETC.

8. ANATOMY OF DIGITAL
COMPUTER
• A DIGITAL COMPUTER IS A COMBINATION OF CERTAIN
VITAL COMPONENTS LIKE
• HARDWARE,
• SOFTWARE ,
• CENTRAL PROCESSING UNIT,
• ARITHMETIC LOGIC UNIT,
• MEMORY,
• REGISTERS,
• MICROPROCESSOR, AND SOME ADDRESSES.

9. CHARACTERISTICS AND
OBJECTIVES OF COMPUTER
CHARACTERISTICS
THE TWO MAIN
CHARACTERISTICS OF A
COMPUTER ARE:
• IT RESPONDS TO A SPECIFIC
SET OF INSTRUCTIONS IN A
WELL-DEFINED MANNER.
• IT CAN EXECUTE A PRE-
RECORDED LIST OF
INSTRUCTIONS (A
PROGRAM).
OBJECTIVES
• IDENTIFY THE BASIC
COMPONENTS OF A
COMPUTER AND THEIR
WORKING
• EXPLAIN THE IMPORTANCE
OF VARIOUS UNITS OF A
COMPUTER
• LEARN HOW THESE UNITS
WORK TOGETHER TO
ACCOMPLISH A GIVEN JOB

10. FUNCTIONS OF COMPUTER
• RECEIVE INPUT —ACCEPT DATA/INFORMATION FROM
OUTSIDE.
• PROCESS INFORMATION—PERFORM ARITHMETIC OR
LOGICAL OPERATIONS ON DATA/INFORMATION.
• PRODUCE OUTPUT—COMMUNICATE INFORMATION TO
THE OUTSIDE WORLD.
• STORE INFORMATION—STORE THE INFORMATION IN
STORAGE DEVICES.

11. SECONDARY STORAGE
DEVICES
• THE OPERATING SPEED OF PRIMARY MEMORY OR MAIN
MEMORY SHOULD BE AS FAST AS POSSIBLE TO COPE UP
WITH THE CPU SPEED.
• THESE HIGH-SPEED STORAGE DEVICES ARE VERY
EXPENSIVE.
• MAGNETIC TAPE
• MAGNETIC DISK
• FLOPPY DISK
• OPTICAL DISK

12. MAGNETIC TAPE
• MAGNETIC TAPES ARE USED FOR LARGE COMPUTERS
LIKE MAINFRAME COMPUTERS WHERE LARGE VOLUME
OF DATA IS STORED FOR A LONGER TIME.
• IN PCS ALSO YOU CAN USE TAPES IN THE FORM OF
CASSETTES. THE COST OF STORING DATA IN TAPES IS
INEXPENSIVE. TAPES CONSIST OF MAGNETIC MATERIALS
THAT STORE DATA PERMANENTLY.
• IT CAN BE 12.5 MM TO 25 MM WIDE PLASTIC FILM-TYPE
AND 500 METER TO 1200 METER LONG WHICH IS COATED
WITH MAGNETIC MATERIAL.

13. MAGNETIC DISK
• THE GRAMOPHONE RECORD, WHICH IS CIRCULAR LIKE A
DISK AND COATED WITH MAGNETIC MATERIAL.
• IT ROTATES WITH VERY HIGH SPEED INSIDE THE DISK
DRIVE.
• DATA ARE STORED ON BOTH THE SURFACE OF THE DISK.
MAGNETIC DISKS ARE MOST POPULAR FOR DIRECT
ACCESS STORAGE.
• HE PRESENCE OF A MAGNETIC SPORT REPRESENTS ONE
BIT (1) AND ITS ABSENCE REPRESENTS ZERO BIT (0).

14. FLOPPY DISK
• IT IS 3.5 INCH IN DIAMETER.
• THE CAPACITY OF A 3.5 INCH FLOPPY IS 1.44 MEGA BYTES.
• IT IS CHEAPER THAN ANY OTHER STORAGE DEVICES AND
IS PORTABLE.
• THE FLOPPY IS A LOW COST DEVICE PARTICULARLY
SUITABLE FOR PERSONAL COMPUTER SYSTEM.

15. OPTICAL DISK
• EVERY APPLICATION AND SOFTWARE THERE IS GREATER
DEMAND FOR MEMORY CAPACITY.
• OPTICAL DISKS CAN BE DIVIDED INTO THE FOLLOWING
CATEGORIES.
• COMPACT DISK/READ ONLY MEMORY (CD-ROM)
• WRITE ONCE READ MANY (WORM)
• ERASABLE OPTICAL DISK

16. INPUT DEVICES
• AN INPUT DEVICE PRESENTS DATA TO THE PROCESSING UNIT
IN A MACHINE-READABLE FORM. A SYSTEM MAY ALSO
SUPPORT VARIOUS OTHER INPUT DEVICES
• OPTICAL CHARACTER RECOGNITION
• MAGNETIC INK CHARACTER RECOGNITION (MICR)
• OPTICAL MARK RECOGNITION (OMR)
• MOUSE
• LIGHT PEN
• SPEECH INPUT DEVICES
• BAR CODE READER

17. OUTPUT DEVICES
• OUTPUT DEVICES RECEIVE INFORMATION FROM THE CPU
AND PRESENT IT TO THE USER IN THE DESIRED FORM.
OUTPUT DEVICES INCLUDE
• DISPLAY SCREEN
• PRINTER
• PLOTTER
• SOUND CARDS & SPEAKERS
• 3D-AUDIO

18. PROGRAMMING LANGUAGES
• A PROGRAMMING LANGUAGE IS A VOCABULARY AND SET OF
GRAMMATICAL RULES FOR INSTRUCTING A COMPUTER.
• PROGRAMMING LANGUAGE REFERS TO HIGH LEVEL LANGUAGES
• BASIC
• C & C++
• COBOL
• JAVA
• FORTRAN
• ADA
• PASCAL

19. OPERATING SYSTEM
• THE OPERATING SYSTEM(OS) IS THE MOST IMPORTANT
PROGRAM THAT RUNS ON A COMPUTER.
• EVERY GENERAL PURPOSE COMPUTER MUST HAVE AN
OPERATING SYSTEM TO RUN OTHER PROGRAMS. MOST
COMMON OPERATING SYSTEMS ARE
• MICROSOFT WINDOWS
• APPLE MACOS
• LINUX
• ANDROID
• APPLE’S iOS

20. EMAIL
• ELECTRONIC MAIL(EMAIL OR E-MAIL) IS A METHOD OF
EXCHANGING MESSAGES BETWEEN PEOPLE USING
ELECTRONIC DEVICES. INVENTED BY RAY TOMLINSON
• EMAIL OPERATES ACROSS COMPUTER NETWORKS
WHICH TODAY IS THE PRIMARILY THE INTERNET. TYPES
EMAIL
• WEB BASED EMAIL
• POP3 EMAIL SERVERS
• IMAP EMAIL SERVERS
• MAPI EMAIL SERVERS

21. APPLICATIONS OF COMPUTER
• COMPUTERS ARE USED EVERYWHERE.
• THEY FOUND THEIR APPLICATION STARTING WITH PLAYING
GAMES TILL PROCESSING SATELLITE IMAGES TO GIVE
WEATHER INFORMATION.
• HOME
• EDUCATION
• INDUSTRIES
• BUSINESS
• ENTERTAINMENT
• GOVERNMENT

22. COMPUTER SECURITY
• COMPUTER SECURITY ALSO KNOWN AS CYBERSECURITY OR IT
SECURITY IS THE PROTECTION OF INFORMATION SYSTEMS FROM
THEFT OR DAMAGE TO THE HARDWARE THE SOFTWARE AND TO
THE INFORMATION ON THEM AS WELL AS FROM DISRUPTION OR
MISDIRECTION OF THE SERVICES THEY PROVIDE.
• CONCERNED WITH FOUR MAIN AREAS
• CONFIDENTIALITY
• INTEGRITY
• AVAILABILITY
• AUTHENTICATION