Basic Computer for IPO Examination and Postmaster Examination

FUNDAMENTALS OF COMPUTER

(10 Marks)

Question Pattern

Abbreviations & Explanation

ANSI - American National Standards Institute

ASCII - American Standard Code for Information Interchange

ALU - Arithmetic Logic Unit

BCD - Binary Coded Decimal

ENIAC - Electronic Numeric Integrator And Calculator

EDVAC - Electronic Discrete Variable Automatic Computer

EDSAC - Electronic Delay Storage Automatic Calculator

EBCDIC - Extended Binary Coded Decimal Interchange Code

EPROM - Erasable Programmable Read Only Memory

IBM - International Business Machines

MODEM - MOdulator/ DEModulator.

PROM - Programmable Read Only Memory

RAM - Random Access Memory (Non-volatile)

ROM - Read Only Memory (Volatile)

UNIVAC - Universal Automatic Computer

WWW - World Wide Web

Terms Usages

World’s First introduced?

First Digital Computer used was UNIVAC - Universal Automatic Computer (1951)

Inventions

General: -

· Computer is a electronic device that can accept input and store data, process it and produce output.

· The father of Computer – Charles Babbage (Introduced first computer on 1830.)

· The Inventor of Computer Mouse – Prof. Douglas Engelbart of Stanford Research Institute.

Generations of Computers

1^st - Vacuum Tubes

2^nd - Transistors

3^rd - Integrated Circuits

4^th & 5^th - Micro Processors

Types of Computers

(1) Super Computer

(2) Main frame

(3) Minicomputers

(4) PCs/Micro Computers

Input devices

A device used to send or feed or put information to a computer is called Input device:

(a) Key Board

(b) Mouse

(c) Track balls

(d) Microphones

(e) Joysticks

(f) Scanners

(g) Digital Cameras

(h) Optical Mark Reader

(j) Optical Character Reader

Output Devices

Devices which are giving the result of the process, is called as Out put devices: -

(a) Monitor

(b) Printer

(c) Projectors

Hard drives are functioning as input as well as output devices.

Memory Storage Devices: -

Primary Storage (Real time storage): -

1. RAM - Random Access Memory (Non-volatile)

2. ROM - Read Only Memory (Volatile)

Secondary Storage Devices: -

(a) Hard Disk

(b) Floppy Disk

(c) Tape Cartridges

(d) Memory Cards

(e) Compact Disks

(f) Digital Versatile Disk (DVD)

(g) Pen/USB Drives

Units for Memory: -

Bit is a smallest storage of memory, is either 0 or 1.

4 bits = 1 nibble 1024 bytes = 1 Kilo Byte

2 nibbles = 1 bits 1024 kilo byte = 1 Mega Byte

8 bits = 1 byte 1024 Mega Byte = 1 Giga Byte

# Hard Disk and Floppy disks are functioning on the basis of Magnetic Media.

# CDs are functioning on the bases of Optical media (Use of Laser Light/beam)

Units/Scale

1. Processor Speed is measured in Hertz.

2. RAM speed measured in Nano Seconds

3. Storage of data / Capacity of Disks is measured in Bytes

4. Hard disk drive speed is measured in RPM (rotation per minute)

5. CDROM Drive efficient is measured in MBPS (1X= 150 MBPS)

Access time - Time taken to complete a movement or transfer or information.

Algorithm - Instructions used to solve problem.

ANSI - American National Standards Institute, Organisation publishes rules, or

standards for the computer industry.

ASCII - American Standard Code for Information Interchange, is the one of the

code used to represent letters, numbers & commands used by the computer.

Data Base is a collection of information, on a subject.

RDBMS is Relational Data Base Management Systems. Oracle, SQL, Cybase are few examples for RDBMS

Hardware - Physical/tangible components of computer

MODEM - Device enables a computer to communicate through Telephone line is called MOdulator/ DEModulator.

The number of Pixels on the VDU (Monitor), expressed as a matrix is called Resolution.

e.g. 640 x 480 (i.e. the monitor contains 640 pixels horizontally across the screen and 480 pixels vertically down the screen).

Network is a process of connecting two or more computers to share resources among them. (e.g.) LAN, WAN, MAN

Memory chips retain data even when Computer is turned off is called Non – Volatile Chips e.g. ROM, SRAM. RAM is a volatile memory.

The CO-processor used for processing Mathematical calculations is called Math Co-processor.

Internet

Internet is spider-net like structure of many-many interconnected computers. It’s governed by ISPs (Internet Service Providers) and Hosts Computers located throughout the world. The theory of internet was emerged when in Cold war days the Army of America was in search of a system which can carry the confidential data and information across his Army bases with swiftness and safely. Then the scientists of America was go through an experiment of connecting LANs of their army bases and developed the base theory of TCP/IP in which data transits through net in small packets and when these packets received at destination the receiving end computer joint them and provide for user info.

Now we are using the second generation of Internet with the bandwidth of 8-32 MHz and very shortly it will be available in Hyper Band with the capacity of 400 MHz.

WWW

World Wide Web, which organizes the Internet related resources easy to access the information available on the net.

Electronic Mail (E-Mail)

Email is the process of sending and receiving messages.

Expended form of COMPUTER

The meaning of computer is CO-ordinated Machine for the PUrpose of Technical and Educational Research

Printer

Printer is one of the output devices. Following are the types of printers available recently: -

(a) Desy Wheel Printer

(b) Line printer

(c) Dot matrix printer

(d) Ink Jet

(e) Bubble Jet

(f) Laser printer

(g) Plotter

Silent features of Line printer:-

(i) Printer is nothing but like a type writer and the same logic (i.e. Hammer method) is used with this machine i.e. printer.

(ii) this printer having the capability to print 30 to 3000 line per minute depending upon the board and mechanism.

(iii) the logic of this printer is very simple that is normally printers are doing print left to right only, at the time of the returning they didn’t doing any job after reaching left most then starting to print it is the common logic for printer

In the case of the line printer to increase the quantity of job at the time of the returning the line printer continuing the job where from they finished this is called zig-zag method because the line printer having the capability to print 30 to 3000 lines per minute.

(iv) this printer is very costly

(v) and it also makes some noisy sounds.

Silent features of Dot Matrix Printers

(i) It is low cost

(ii) It will print the character as dot forms and fulfill the line after the doing two or three times for a line

(iii) It makes noisy sound

Some important terminology with description: -

ARCHIE

A search tool for use with FTP that searches an Archie site (a database of file names) for a specific filename.

ARPANET (Advanced Research Projects Agency Network)

The predecessor of the Internet, in use between 1971 and 1990, connecting military and academic institutions. Officially dismantled in 1990.

CERTIFICATE AUTHORITY

An organization that issues digital certificates. A CA is responsible for guaranteeing a certificate holder's identity.

CGI (Common Gateway Interface)

A specification for transferring information between a Web server and a CGI program. The programs can be written in any language like C, Peri, Visual Basic, Java, as long as it conforms to CGI specifications. CGI makes it possible for Web Servers to dynamically interact with users. The most common use of CGI is seen in online forms.

CLIENT

When you access a service on a computer, then your computer is the client, while the other one is called the server. Services include file and print e-mail, Web, etc.

DIGITAL CERTIFICATE

An attachment sent along with a message for authentication purposes. A digital certificate verifies that the user sending the message is who he or she claims to be.

DIRECTORY SERVICE

A service that stores information on the network in a hierarchical format for easy accessibility. It can store information about applications, equipment, and users on a network.

DOMAIN

A group of computers that function under common rules. On the Internet, it's put as an extension in a host name for identifying the types of host. Various domain types have been identified. These include.com (company/commercial), .edu (educational institutions), .gov (government), .mil (military), .org (organization). Outside the domain name is a 2-letter country code (.in for India).

DNS (Domain Name System)

A System used on the Internet to translate IP address into easy to remember names. The service that does this translation is called DNS. DNS servers are connected with each others over the internet. So, if one DNS server doesn't have an IP address translation in its table, it queries other systems running DNS to find out.

DOWN LOAD

To copy a file from a remote machine, for example, with anonymous FTP, or when you want to copy a program from a website and save it to your hard disk.

DHCP (Dynamic Host Configuration Protocol)

A protocol used for dynamically assigning IP address to clients that request for it. When configuring a DHCP server, a pool or range of IP addresses has to be given. The server then uses DHCP to assign the IP address from this pool.

DHTML (Dynamic HTML)

Refers to Web pages that change their contents depending on client request.

FINGER

A standard utility that is part of the TCP/IP protocol stack that lets you determine who is a valid user and who is logged into a system you have access to. It's used in UNIX based systems. The syntax is finger username@domain.name, or finger@host.

FIREWALL

A system to prevent unauthorized access to a private network. A firewall is used on a network directly connected to the Internet to prevent outside Internet users from accessing it.

FREEWARE

Software that is distributed free of charge, but often without customer service or much documentation.

FTP (File Transfer Protocol)

A simple program to transfer files over a network from one computer to another. Many FTP servers allow you to download files with out having an account on the machine, by using anonymous or FTP for a user name and your e-mail address as a password. This is a major means of distributing software and info on the Internet.

GATEWAY

A device that is connected to the Internet, and allows other machines inside a company's network to access the Internet. In other words, it's the connection point between a LAN and the Internet. The device can be a specialized piece of hardware like a router, or it can be software installed on a computer.

GIF (Graphics Interchange Format)

A standard graphics image format used on the Internet.

GOPHER

A menu-based system for organizing and distributing information on the Internet. It's similar to FTP as it lets users browse or download files and directories. A key feature of Gopher is the ability to include menu items that connect the user to other Gopher servers. Gopher is no longer in popular use.

HACKER

Originally this term refer to crackerjack programmers and computers experts and connoted respect. Through this meaning is still in use, this word now also in use (specialy by the media) to refer to people who deliberately try to penetrate the security of other computers. The computers use community prefers to call these people crackers.

HEADER

Information in the beginning of a piece of data being sent over a network that describes its content, the destination address, etc.

HOMEPAGE

An HTML document that servers as the main access point to a company's Website.

GUEST

When you connect to or log onto a remote computer on which you don't have your own account, (perhaps using a special account for guests) you are referred to as a guest or visitor.

HTML (Hyper Text Markup Language)

A simple and easy to learn programming language that Web documents are written in.

HTTP (Hyper Text Transfer Protocol)

The protocol used on the Internet to transfer HTML documents. All Web browsers use this protocol to read the Web pages.

HYPERTEXT

A new concept for organizing information made possible by computers, where keywords or phrases can be used not only to reference additional resources, but also serve as software links to these resources.

IMAP4

The Internet Message Access Protocol lets you view your e-mail at the server mailbox as an extension of your computer. You can view, delete and search for mail on the server, and only down load the ones you need to your local machine.

INTERFACE

The manner in which a user provides information to a computer program. Some examples are GUI for graphical user interface and CLI for command line interface.

INTERNET

The internet is the Grand Daddy of all networks. It's a collection of computers and computer networks across the world that communicates across dedicated high-speed phone lines using a single protocol family called TCP/IP.

IP ADDRESS

A unique set of four numbers between 1 and 254 separated by periods, such as 209.194.84.60, used to identify every machine connected to the Internet. As these numbers are very difficult to remember, they are mapped to an easy to remember name, which is called the host name.

IRC (Internet Relay Chat)

A program that allows multiple users to conduct typed conversation in real time over the Internet.

ISO (International Organisation for Standardization)

An International body made up national standard bodies from over 75 countries. It's engaged in defining standards. The most popular computer standard define by ISO was the OSI model.

ITU (International Telecommunication Union)

An international body engaged in defining telecommunication standards.

JPEG (Joint Photographics Expert Group)

A standard (compressed) format for colour images commonly used on the Internet. They use the JPG or JPEG extensions.

JUGHEAD (Jonzy's universal gopher hioerachy excavation and display)

A powerful gopher search tool written by Rhatt "Jonzy" Jones.

KERMIT

A simple modern protocol for transferring files between Macs and/or PCs, or from these to bigger computers. Since TCP/IP was adopted as the official Internet protocol in 1983, most PCs software has abandoned Kermit. However, Kermit and its cousins X-, Y-, and Z- modern are still needed in the absence of an Ethernet or SLIP connection.

LDAP (Lightweight Directory Access Protocol)

A set of protocols for querying information directories. There are various directory services on the Internet that can be queried for information. LDAP is being used in operating systems like the upcoming Windows 2000 and NetWare for querying their directory services. LDAP is a simpler version of the X.500 directory service standard.

LYNX

A text only Web browser.

MAILING LIST

A mechanism for simultaneously distributing e-mail messages to a group of e-mail users who have subscribed to the list. A common use of mailing lists is in newsletter subscriptions.

MIME (Multipurpose Internet mail Extensions)

A way to encapsulate binary file attachments, such as images and sound into e-mail messages. The method was originally suggested in RFC-1341.


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