FUNDAMENTALS
OF COMPUTER
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
1st - Vacuum
Tubes
2nd - Transistors
3rd - Integrated Circuits
4th & 5th - 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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