Computer Fundamental

minesh sachan

Sample Questions

1. The Computer is an electronic device that ___________.
a) Accepts (reads) data from the input device
b) Processes the data by performing calculations and operations on it as
per instructions
c) Generates (writes) the desired output results on to the specified output
devices.
d) All the above
2. The First generation of computers started using _______________ as the basic
components for memory and circuitry for CPU.
a) vacuum tubes
b) vacuum cleaner
c) vacuum pump
d) None of the above
3. CPU stands for___________________.
a) Control Processing Unit
b) Central Performance Unit
c) Central Processing Unit
d) Control Performance Unit
4. e-Governance uses a range of modern Information and Communication Technologies
such as_______________________
a) Internet
b) Mobiles/ Tablet
c) Laptops/ Computers
d) All the above
5. Assembly language is a representation of___________________.
a) Assembly Languages
b) Machine language
c) High level Languages
d) None of the above

Answers:
1. d
2 a
3. c
4. d
5. a

Assessment 2 (True/False)
1. The data input, given to the computer in the form of digits, alphabet, symbols, video,
audio.
a) True
b) False
2. Keyboard, mouse, light pen, microphone, touch screen, joystick are few output
devices.
a) True
b) False
3. Input devices are devices used to input data or information into a computer.
a) True
b) False
Answers:
1. a
2 b
3. a

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Introduction to Computer

  • Computers are machines that perform tasks (or) calculations according to a set of instructions.
  • The Computer is an electronic device that,
    • Accepts (reads) data from the input device
    • Processes the data by performing calculations and operations on it as per instructions
    • Generates (writes) the desired output results on to the specified outputØ
  • Nowadays, computers are an important part of our lives.
  • The term “Computer” is derived from the Latin word “Computare” which means “to compute” or “to calculate”.
  • It was originally invented to make calculations quickly and precisely.

Major Components of Computer

  • The major components of a computer are:
    • Central Processing Unit (CPU)
    • Memory Unit
    • Input Unit
    • Output Unit



Central Processing Unit (CPU)

  • The CPU is the heart of the computer, this unit actually executes instructions.
  • The major sections of CPU are:
    • Control Unit (CU)
    • Arithmetic and Logical Unit (ALU).

Control Unit (CU)

  • Controls the operations that take place in various parts of a computer byv sending electronic signals.

Arithmetic Logic Unit (ALU)

  • It performs all arithmetic and logical operation for program execution.v

Memory Unit

  • Memory is a device that stores computer’s data and programs.
  • The two types of memory are
    • Primary Memory (Internal)
    • Secondary Memory (External)

Input Unit

  • This unit is used to give data to the computer by the user.
  • Keyboard, mouse, light pen, microphone, touch screen, joystick are few input devices.

Output Unit

  • This unit is used to display result generated by the computer.
  • Monitor, printer, speaker are a few direct output devices.

History of Computers

  • During the 20th century, at the initial stage calculations were done by mechanical computing devices.
  • “Abacus” was the first mechanical computing device introduced by the Chinese.
  • It is a manual calculating device used for addition and subtraction.
  • Napier’s bones were the next device for multiplication by an English mathematician, John Napier in the 16th century.
  • In 1673, Leibniz’s multiplication and dividing machine were introduced which could do both multiplication and division.
  • Punch card system was developed in 1801 by Jacquard.
  • Then “Analytical machine” was developed by Charles Babbage that was intended to be completely automatic.




First generation computer (Not in use)

  • The period of first generation computer was 1940-1956 using vacuum tubes.
  • Hardware technology

The First generation of computers started using vacuum tubes as the basic components for memory and circuitry for CPU (Central Processing Unit).

 

  • The input to the computer was through punched cards and paper tapes.
  • The output was displayed as printouts.
  • Examples
  • EDVAC (Electronic Discrete Variable Automatic Computer)
  • EDSAC (Electronic Delay Storage Automatic Calculator)
  • UNIVAC (UNIVersal Automatic Computer)
  • ENIAC (Electronic Numerical Integrator And Computer)




Second generation computer (Not in use)

  • The period of second generation computer was 1956-1963 using transistors.
  • Examples
  • PDP-8, IBM 1401, CDC 1604 and IBM 7090

Third generation computer

Third generation computer (Not in use)

  • The period of third generation was 1964-1971 using Integrated Circuits (IC’s)
  • Examples
  • NCR 395, B6500, IBM-360, IBM-370, PDP 11.
  • Disadvantage
  • Limited storage capacity.
  • Application
  • Computers were produced commercially, and were smaller and cheaper than the first and second generation computers.
  • Used for both commercial and scientific applications.
  •  
  • Fourth generation computer

 

  • The period of the fourth generation was 1971-Present using Large Scale Integration (LSI) and Very Large Scale Integration (VLSI) circuits.
  • The fourth generation computers were designed by using a microprocessor.
  • Examples
  • Intel 4004 chip was the first microprocessor.
  • IBM introduced the first computer for home use in 1981.
  • In 1984, Apple introduced the Macintosh.
  • Disadvantage
  • The latest technology and highly skilled staffs are required for manufacturing of microprocessors, so it is difficult to build.
  •  
  • Fifth generation computer
  • The period of fifth generation is present and beyond date using Ultra Large Scale Integration (ULSI).
  • Recent research has focused on developing the “thinking computers” that is “Artificial intelligence (AI)”.
  • This generation is based on parallel processing hardware and AI (Artificial Intelligence) software.


Components of Computer System

  • Central Processing Unit (CPU)
  • The Central Processing Unit (CPU) is the brain of the computer, it is a part of a computer which interprets and executes instruction.

 



• The Central Processing Unit (CPU) is the brain of the computer, it is a part of a computer which interprets and executes instruction

  • The task of performing operations like arithmetic and logical operations is called processing.
  • The CPU takes data and instructions from the storage unit and makes all sorts of calculations based on the instructions given and the type of data is provided. It is then sent back to the storage unit.
  • It processes the instructions that it collects by decoding the code in programs.

Functional block of CPU

The two components in CPU are,

  • Arithmetic and logic unit (ALU)
  • Control Unit (CU)
  • Arithmetic and logic unit (ALU)
  • The ALU performs arithmetic and logical operations.
  • Arithmetic operations include addition, subtraction, multiplication and division.
  • Logical operations compare numbers, letters and special characters.
  • The ALU is a fundamental building block of the Central Processing Unit of a computer.
  • Control Unit (CU)
  • A Control Unit (CU) handles all processor control signals.
  • It directs all input and output flow, fetches code for instructions from microØ
  • programs and directs other units and models by providing control and timing signals.
  • Control Unit is designed in two ways
  • Hardwired control
  • Micro program control
  • Micro program control
  • Micro programs are stored in a special control memory and are based on flowcharts.
  • They are replaceable and ideal because of their simplicity.



Printer

  • A printer is an electromechanical device which converts the text and graphical documents from electronic form to the physical form.
  • Generally they are the external peripheral devices which are connected with the computers or laptops through a cable or wirelessly to receive input data and print them on the papers.
  • A wide range of printers are available with a variety of features ranging from printing black and white text documents to high quality colored graphic images.
  • Quality of printer is identified by its features like color quality, speed of printing, resolution etc.
  • Modern printers come with multipurpose function i.e. they are combination of printer, scanner, photocopier, fax, etc

Types of printer

There are different types of printers and those are,

  • Dot matrix printer
  • Inkjet printer
  • Laser printer
  • Dot matrix printer
  • It is a popular computer printer that prints text and graphics on the paper by using tiny dots to form the desired shapes.
  • Inkjet printer
  • Inkjet printing is a type of computer printer that creates a digital image by propelling droplets of ink onto paper, plastic, or other substrates.
  • Laser printer

Laser printing is an electrostatic digital printing process that rapidly produces high quality text and graphics by passing a laser beam over a charged drum to define a differentially charged image



Plotter

  • The plotter is a computer printer for printing vector graphics.
  • A plotter is a printer that interprets commands from a computer to make line drawings on paper with one or more automated pen.
  • A plotter is a computer hardware device similar to a printer that uses a pen, pencil, marker or other writing tool to make a design.
  • Computer Memory
  • Computer memory is a device that stores computer’s data and programs.
  • It stores program, data results or any kind of information.
  • Memory stores binary information, i.e. 0’s and 1’s in internal storage areas in the computer.
  • Moreover, the term memory is usually used as a shorthand for physical memory, which refers to the actual chips capable of holding data.



Types of Memory

  • The computer memory is divided into two types are,
    • Primary or main memory
    • Secondary memory
  • Primary memory
  • Primary memory is used for immediate access of data by the processor.
  • Most computer systems around the world use primary memory.
  • While primary memory storage demonstrates faster processing ability, it is costly and hence is not largely used for data storage.
  • Primary memory can be divided into two types.
  • RAM (Random Access Memory)
  • ROM (Read Only Memory)

 

  • RAM (Random Access Memory)
  • RAM is the central storage unit in a computer system.
  • It is the place in a computer where the Operating System, application programs and the data in current use are kept temporarily so that they can be accessed by the computer’s processor.
  • The information stored in the RAM is typically loaded from the computer’s hard disk, and includes data related to the Operating System and certain applications.
  • There are primarily two forms of RAM:
  • Static RAM (SRAM)
  • Dynamic RAM (DRAM)
  • Static RAM (SRAM)
  • SRAM is more expensive among other forms of RAMs, SRAM uses bistable latching circuitry to store one bit each, and hence it is faster than its counterpart.
  • Its high price prevents it from being widely used in everyday computing machines, but many modern machines use SRAM as the processor’s cache register.
  • Dynamic RAM (DRAM)
  • DRAM is widely used in modern computers as primary memory, DRAM is slower than SRAM, but is inexpensive due to its one transistor-one capacitor paired assembly of memory storage.
  • The Example of dynamic RAM such as DDR2, DDR3 RAM.

 

  • ROM (Read Only Memory)
  • Unlike RAM, ROM is a permanent form of storage. ROM stays active regardless of whether the power supply to it is turned on or off.
  • In spite of this, ROM was used (in rare cases is still used) as the primary device for most computers back in the 80’s. This was because ROM devices do not allow data stored on them to be modified.
  • As the name itself suggests, data can only be accessed and read by the user, not overwritten, upgraded, or modified.
  • It is an ideal choice for bootable devices for old computers, programmable interpreters, and the portable OS files carrier.
  • The system programs stored on a ROM device could never be altered and hence, stayed secure for use.

 

  • Secondary memory
  • Secondary memory refers to storage devices, such as hard drives and Solid State Drives (SSD). It may also refer to removable storage media, such as USB flash drives, memory chips/cards, CDs, and DVDs.
  • Secondary memory is much slower than primary memory, however, it typically offers a far greater storage capacity.
  • For example, a computer may have a one Terabyte hard drive, but only 16GB (gigabytes) of RAM. That means the computer has roughly 64 times more secondary memory than primary memory.
  • Additionally, secondary memory is non-volatile, meaning it retains its data with or without electrical power. RAM on the other hand, is erased when a computer is shut down or restarted. • Therefore, secondary memory is used to store “permanent data,” such as the Operating System, applications, and user files.
  • The secondary memory, such as
  • Floppy disk
  • Magnetic tape
  • Hard disk drive
  • Optical disk




Software

  • Software is a collection of instructions that enables the user to interact with a computer, this set of instruction is often called as a “program”.
  • A program is a sequence of instruction written to solve a particular problem.
  • The software is all the instructions written for the computer’s hardware to function properly.
  • For example, without your internet browser software user cannot browse the internet or read this page and without a software Operating System the browser would not be able to run on the user’s computer.
  • Program: A finite set of sequence of instructions.
  • Software is often packaged on CD-ROMs and diskettes or downloaded from the internet.
  • Today, much purchased software is downloaded over the Internet.

Examples of computer software are

  • Windows Operating System
  • Microsoft Office
  • Device Driver software
  • Assembler and compiler software

 

Note: Above mentioned software are of the respective vendors.

Types of Software

  • There are two categories of software are:
  • Application software
  • System software

Application Software

  • Application software is computer software designed to help the user to perform singular or multiple related specific tasks.
  • They act as instructions which direct the hardware to perform specific functions.
  • Application software cannot be operated unable to run without the Operating System and system utilities.
  • Application software can be used as a productivity/business tool; to assist with graphics and multimedia projects.
  • Examples of Application Software are
  • Microsoft Word
  • Microsoft PowerPoint
  • Macromedia Freehand
  • Adobe Photoshop
  • CorelDraw

 Note: Above & below mentioned software/Logos are of respective vendors.

Types of Application software

  • General purpose application software is designed to satisfy common needs of various businesses such as,
  • Word processing software
  • Database software
  • Multimedia software
  • Educational software
  • Application suites
  • Word processing software
  • Word processing software enables users to create and edit documents.
  • The most popular of this type of software are MS-word, WordPad.
  • Database software
  • A database is a structured collection of data.
  • This database software allows users to store and retrieve data from databases.

Examples are MS Access, File maker pro and Apple works etc.

  • Multimedia software
  • The multimedia software allows users to create and play audio and video files.
  • They are capable of playing all types of media files.
  • Examples of this type of software are Windows Media player and RealTek Real player.

Educational software

  • The educational software has the capabilities of running tests and tracking progress.
  • It also has the capabilities of collaborative software.
  • This type of software is often used in teaching and e-learning.
  • Some of the well-known dictionaries like Britannica, Encarta are using this software.

Note: Above mentioned software are of respective vendors.

Application suites

  • An application suite consists of a group of applications combined top perform related functions.
  • These application suites come as a bundle of applications like Word processor, Spreadsheets, Presentation software etc.

Features of application software

  • Application software is close to users.
  • This software is easy to understand and manipulate.
  • Application software is easy to design.

Types of System Software

  • Operating System (OS)
  • Utility Programs

Operating System (OS)

  • Operating System is an important system software found almost in all computers.
  • Operating System is defined as the program, that instructs the computer how to work with its various components.
  • It helps to manage files and checks the various peripheral devices such as printers, monitors, etc.
  • The OS itself is a collection of programs, these programs translate our instructions to the computer’s language and then translate the computer’s response from computer’s language to the user understandable form.

Utility Programs

  • Utility software is a type of system software designed to help analyze, configure, optimize and maintain the computer.
  • A single piece of utility software is usually called a utility or tool.
  • Utility software should not be confused with application software, which allows users to do things like creating text documents, playing games, listening to music or surfing the web.
  • Rather than providing these kinds of user-oriented or output-oriented functionality, utility software usually focuses on how the computer infrastructure (including the computer hardware, operating system, application software and data storage)operates.
  • Due to this focus, utilities are often rather technical and targeted at people with an advanced level of computer knowledge.
  • Examples of utility software include,
  • Virus scanner – to protect your system from trojans and viruses
  • Disk defragmenter – to speed up your hard disk
  • System monitor – to look at your current system resources
  • File managers – to add, delete, rename and move files and folders



Computer – Number system

  • The data input, given to the computer in the form of digits, alphabet, symbols, video, audio, etc., is understood by computer only as 0’s and 1’s. It converts all input data into 0’s and ‘1s.
  • Each character is represented as a unique combination of 0’s and 1’s.
  • Number system is a way to represent a number.
  • Number system used in the computer and is classified into:
  • Decimal number system
  • Binary number system
  • Octal number system
  • Hexadecimal number system

Decimal number system

  • The prefix- “deci-” stands for 10.
  • The decimal numbers are specified with base or radix (10). For e.g. 3456(10) or 3456.
  • It consists of 10 digits- 0,1, 2,3,4,5,6,7,8 and 9.

• In the decimal number system, the successive position to the left of the decimal point represents units, tens, hundreds, thousands etc.,



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