* STD Standard Trunk Dialing
* ISD International Subscriber Dialing
* SMS Short Message Service
* MMS Media Message Service
* PABX Private Automatic Branch eXchange
* CDMA Code Division Multiple Access
* GSM Global System for Mobile communication
* ENIAC Electronic Numerical Integrator and Calculator (1946, First Electronic Computer)
* EDVAC Electronic Discrete Variable Automatic Computer
* CPU Central Processing Unit
* ALU Arithmetic and Logical Unit
* RAM Random Access Memory
* ROM Read Only Memory
* CLI Command Line Interpreter
* GUI Graphical User Interface
* BIOS Basic Input Output System
* IBM International Business Machines
* DTP Desk Top Publishing
* LINUX Linus Uniplexed Information Computing System (Graphic User Interface)
* UNIX Uniplexed Information Computing System (Character User Interface)
* DOS Disk Operating System
* WINDOWS window for computer
* FAX- Facsimile Machine
* MICR Magnetic Ink Character Recognition
* OCR Optical Character Recognition
* OMR Optical Mark Recognition
* ASCII American Standard Code
* BIT Binary Digit
* MIDI Musical Instrument Digital Interface
* MPEG Moving Pictures Expert Group
* JPEG Joint Photographic Expert Group
* AVI Audio Visual Information
* PNG Portable Network Graphics
* BASIC Beginners All Purpose Symbolic Instruction Code
* COBOL Common Business Oriented Language
* FORTRAN FORmula TRANslation
* ANSI American National Standards Institute
* URL Uniform Resource Locator
* ISDN Integrated Services Digital Network
* VSAT Very Small Aperture Terminal
* TCP/IP Transmission Control Protocol/ Internet Protocol
* Generations of Computers
* 1st Generation Computers Vacuum Tubes
* 2nd Generation Transistors
* 3rd Generation Integrated Circuits (Chips)
* 4th Generation LSIC, VLSIC
* 5th Generation Thinking Machines (Turing Machine)
* Types of Computers (based on electric signal)
* Analog flight simulators
* Digital commercial and control systems
* Hybrid ECG machines, Modem
* Types of Computers (based on Size)
* Microcomputer 8bit microprocessor chips, IBM PC
* Minicomputer
* Mainframe computer DEC, ICL, IBM 3000 series
* Super computer CRAY YMP, PARAM, CRAY2, NEC SX-3
* Natural Languages LISP, PROLOG
* Transistor (1959) an electronic device which can replace several hundreds of Vacuum Tubes
* Characteristics of computer speed, accuracy, versatility, diligence, storage capacity
* Bootstrap loader The initial startup program which is stored in ROM and whose function is to start the operation of the computer system(booting) once the power is turned on.
* RAM is a primary memory and volatile memory which has limited storage capacity.
* Primary memory is accessible directly by the Processing Unit
* ROM It stores some standard processing programs supplied by manufacturer to operate PC
* Storage of program and data in ROM is permanent.
* ROM can only be read by CPU but it cannot be changed.
* PROM(Programmable) In PROM, possible to store program but cant be altered or erase later
* EPROM(Erasable, Programmable) Overcomes the problems of PROM and ROM
* Inf. Stored in EPROM is erased by exposing it to UV light.
* EAPROM(Electrically Alterable) memory can be altered by using electric signals
* Cache Memory small memory chip attached between CPU and Main memory. Accessed much faster than conventional RAM.
* Secondary Memory(Auxiliary Memory) two types: Magnetic & optical
* Magnetic hard disk stack of metal disks sealed in a box(rewritable)
* Optical CD, DVD, Pen drives, zip drives
* WORM Write Once Read Many
* IN/OUT devices:
* Input Keyboard, Mouse, Trackball, light pen, touch screen, MICR, OMR, BCR, Scanner
* Output Monitor, Printer, Plotter, FAX(Facsimile Machine), Speakers
* Printer types:
* Impact Dot Matrix, Character printers
* Non Impact InkJet, DIskJet, Laser, Thermal Printers
* Software Set of programs (or instructions) that makes hardware perform set of tasks in particular order
* System software MS Dos, UNIX, Linux
* Application software software for specific application
* Translators Compilers and Interpreters
* Compiler special program that processes statements written in a particular programming language (source code) and converts to machine code.
* It is a translator program which reads entire program written in high level language and converts it into machine language code
* Interpreter Translates high level language into intermediate form which it then executes. Time consuming is program is long.
* It is a translator which converts one statement of program into machine code, execute it and then goes on to perform the same for next statement, and continues till end of program or occurrence of an error
* Computer Security :
* Virus Program written to interface with normal functioning of the computer
* Boot sector virus infects bootsector in harddisk and affects partition table
* File viruses attach with exe files. Commonly infects files with com or exe extensions
* System Viruses Infects specific system files such as command.com
* Viruses can be grouped as:
* Time bomb It will start on particular date at particular time. Computer looses its ability to function properly
* Trojan Horse Enters computer via email or free programs that are downloaded
* Worm Infiltrate legitimate data processing programs and alter or destroy data
* Often use network connections to spread from one system to other
* Linked through communication lines
Digital Computer
* CPU also known as Brain of Computer
* Computer Functions Receive inputs, Process information, Produce output, Store information
* Registers Additional storage locations. Present in CU and ALU make processing efficient.
* Address to locate characters of data or instructions computer stores them in location called address
* Legal aspects:
* Copyright intellectual property; it encourages artists, designers, authors to create original works by rewarding them with exclusive right to a limited period to exploit the work for monetary gain
* Disclaimer It is an acknowledgment by the author/ creator of web page that he doesnt claim any accuracy, completeness, or usefulness of information and contents disclosed in web
* Digital Signature It is an encryption and decryption process allowing both the positive identification of author of an electronic message and verification of integrity
Microsoft Office
* Excel:
* A workbook opens with three worksheets and it can have a maximum of 255 worksheets
* Entering Formulas:
* Must start with an = sign
* Mathematical operators(+-/*%) and Relational operators(>< ), text
* Reference of cells
* Functions related to worksheets (ex. SUM, AVERAGE ets)
* & is used to join texts(concatenate) in quotation marks
* PowerPoint:
* In both normal view and outline view you can see current slide, slide outline, notes
* 9 no of slide layouts available in New Slide dialog box
* Slideshow view is used in presentation of slides in a conference
* Insert text in a slide Using outline text, inserting text boxes
* Add notes to Slides in Normal View
* Text can be easily entered into slides using Normal view, Outline view
Internet & Networking
* Protocol It is a set of rules that govern data communication
* Communication devices:
* Wire pairs local telephone commn. Short distance digital data commn.
* Twisted pairs copper wires twisted in pairs. Helps reduce cross talk, EMI
* Comes in two forms Unshielded and Shielded Twisted Pairs, UTP and STP
* Ethernet IEEE 802.3 4 pairs of Cu cables both voice and data transmission
* Coaxial cable cable TV, office buildings and LANs
* Optical Fibre glass fibre wrapped in protected in protective layers
* Carries data by means of pulses of light
* Communication Services:
* Baud rate number of bits per second
* Narrow band, voice band, broadband
* Modem A modem modulates outgoing digital signals from a computer or other digital device to analog signals for a conventional copper twisted pair telephone line and demodulates the incoming analog signal and converts it to a digital signal for the digital device
* Properties of Networking:
* Facilitate communications
* Permit sharing of files, data, and other type of information
* Share network and computer resources
* Types of Network:
* LAN supplies networking for group of computers in close proximity
* Ethernet cables, hubs, and Network adapters
* Ex schools, colleges, firms etc.
* WAN network which covers a larger geographical area
* Uses communication circuits to connect intermediate nodes
* Ex Ethernet (Xerox), ARPANET (Adv. Research Projects Agency US)
* MAN serves role to an ISP, but for corporate users with larger LANs
* Ex Cellular or mobile phone network
* Imp Terms:
* Voice messaging similar to electronic mail which is an audio message
* Hub Anything that comes in one port is sent out to the others
* Switch similar to hub but pays attention to traffic that comes across it
* Router it is as a computer can be programmed to understand, manipulate, and route the data its being asked to handle
* Network Repeater repeater connects two segments of network cable, regenerates the signals to proper amplitudes and send them to other segments
* Operates at physical layer of OSI
* Bridge it reads outermost section of data on data packet, and tells where the message is going
* It occurs at the Data link layer of OSI
* Gateway it can translate inf b/w diff n/w data formats or network architectures
* Operate at application layer. Can also operate at network or session layer of OSI
* CN and Communication:
* Analog signal transmission pattern is in a continuous wave form
* Measured in Volts and Frequency in Hz.
* Digital signal it assumes a discrete set of values over a given range
* Sequence of voltage represented in binary form
* Communication types:
* P to P Commn peer to peer or point to point network where a single commn channel is not shared by all nodes
* Ex MAN, WAN
* Broadcasting - network has single commn channel that is shared by all the other nodes
* Ex LAN
* Network Topology:
* BUS - connects networking comp along a single cable or series of cables that are connected linearly
* RING network stations are connected along a single path whose ends are connected to form a circle
* STAR number of work stations are directly linked to central server
* Communication protocols:
* Protocol procedure of data transmission in form of software (or)
* It is a set of rules that tells computer know how to interpret inf at that address
* Data sequencing, data routing, flow control, error control
* Data transmission Modes:
* Simplex communication takes place in one direction
* Half duplex commn channel is used in both directions but one at a time
* Full duplex commn channel used in both directions at the same time
* Internet (network of networks):
* Internet is not a government body. Entire authority lies with Internet Society.
* E-mail (electronic mail) paperless method of sending messages, notes, or letters from one person to other
* Offline editing/composing/reading can be done.
* Intranet it is the use of internet technology for communication within the firm and those organizations and individuals with whom the firm does business
* Vinod.gali@gmail.com
* Vinod.gali local part, name of the mailbox or the destination computer
* Gmail mail server
* .com type of organization on net, which is hosting the mailbox
* Com commercial institutions or organization
* Edu educational institutions
* Org private organizations
* Gov government site
* Mil military site
* Net Gateways and administrative hosts
* FTP Internet utility s/w used to upload or download files
* Can login to FTP site with username anonymous and email address as password
* TELNET (Remote Computing) telecommn utility s/w, uses available telecommn facility and allows to become a user on a remote computer
* WWW (world wide web or The web) hypertext based information retrieval tool
* Surfing process of using browser to view inf on internet
* URL (Uniform Resource Locator) the address on the internet
* Ex http://www.gali.org/simha/vinod.htm
* Protocol is followed by a colon (http), FTP, NEWS( Usenet News groups protocol) , GOPHER( alternative transfer protocol), TELNET
* Server is preceded by (//www.gali.org)
* Each name of the segment is preceded by /
* Types of Internet connections:
* Gateway access (Level one access) Access to internet from a network, which is not on the internet.
* Dial up connection (Level two) provides conn to internet through a dial-up terminal conn
* Shell Connection user gets only textual matter of webpage. Doesnt support graphics
* TCP/IP it can display both text and graphics
* ISDN high speed internet through the use of digital phone lines
* Leased Connection (Level three) secure, dedicated and most expensive level of internet connection.
* DSL (Digital Subscriber Line) connects home or office through same telephone line that comes through street
* VSAT an earthbound station used in satellite commn of data, voice and video signals, excluding broadcast television.
* Spamming Act of sending unsolicited emails
* HTML:
* Hyper Text Markup Language; platform independent; tags;
* Format: < HTML>
* Attributes of :
* BGCOLOR background color for the document
* MARGINS set left, top margins (LEFTMARGIN, TOPMARGIN)
* BACKGROUND point to an image file, that will be tiled across document
* Tags:
* Container tags tags having both opening and closing tags
* Ex - ,
* Empty tags tags having only opening and no ending.
* Ex -
,
*
- Pre Formatted text
* browser preserves spaces and line breaks for the text written inside the tag
*
attributes WIDTH, SIZE, ALIGN, NOSHADE, COLOR
* , , , , , ,
* - COLOR, SIZE (default font size -3), FACE
* Special characters
* - &cop
* - ®
* - ¼
* Divide, < ,>,< =, >= - ÷, <, >, &le, &ge
* & - &
* Spade, clubs, heart - &spades, &clubs, &hearts
* Ordered List Numbered List -- COMPACT, TYPE (A, a, I, I, 1), START (START=5 => starts with either E, e, v, V, 5 depending on type)
Unordered List Bulleted List -
*- ALIGN, HEIGHT, WIDTH, VSPACE, HSPACE, ALT, BORDER
* - anchor tag NAME (to identify a section with a name)
* Java:
* Characteristics Simple and small, Object Oriented (Encapsulation, Polymorphism, Data Binding, Inheritance), Portable and Interpreted, Architecture Neutral, Dynamic, Distributed, Automatic memory management, Multi threaded, Robust, Secured
* Classes they are fundamental entities of java
*
System Analysis and Design
* SDLC
* Organizational process of developing and maintaining systems
* Requirement analysis design coding testing maintenance
* Decision Table
* Chart with four sections; top section has title, date, author, system and comments
* Condition stub list of necessary steps in a decision table
* Action stub write all processes desired in a given module
* Condition entry all possible permutations yes or no responses
* Action entry whether an action should occur as a consequence of condition entry
* Decision Tree
* Defines condition as a sequence of left to right tests
* It turns decision table in to a diagram
* Data Processing Activities:
* Collection, Conversion, Manipulation, Storage, Communication
* Data Organization:
* Data item smallest unit of information stored in a computer file
* Field data items are physically arranged as fields in a computer file
* Record it is a collection of related data items or fields
* File collection of records
* Database collection of related files
* OOPS:
* Object object contains data and code to manipulate data
* It can interact without knowing details of each others data and code
* Objects are variables of type class
* Class Entire set of data and code can be made a user defined data type with the help of a class
* Data Abstraction abstraction refers to act of representing essential features without including background details
* Encapsulation combining both data and functions that operate on that data under a single unit
* Modularity act of partitioning a program into individual components is called as modularity
* Inheritance It is a capability to define a new class (derived class) in terms of an existing class (base class)
* Polymorphism It is the concept that supports the capability of data to be processed in more than one form
GV Simha
