software

PHOTOSHOP PRACTICAL WORKS

ADVT

data communication

DATA COMMUNICATION AND COMPUTER NETWORKS

Communication is defined as transfer of information, such as thoughts and messages between two entities. The invention of telegraph, radio, telephone, and television made possible instantaneous communication over long distances. In the context of computers and information technology (IT), the data are represented by binary digit or bit has only two values 0s and 1s. In fact anything the computer deals with is 0s and 1s only. Due to this it is called discrete or digital. In the digital world messages, thoughts, numbers. etc can be represented in different streams of 0s and 1s. 

Data communications concerns itself with the transmission (sending and receiving) of information between two locations by means of electrical signals. The two types of electrical signals are analog and digital. Data communication is the name given to the communication where exchange of information takes place in the form of 0s and 1s over some kind of media such as wire or wireless. The subject-Data Communications deals with the technology, tools, products and equipment to make this happen. In communications and information processing, encoding is the process by which information from a source is converted into symbols to be communicated. Decoding is the reverse process, converting these code symbols back into information understandable by a receiver.

 Entire data communication system revolves around three fundamental concepts.

• Destiny: The system should transmit the message to the correct intended destination. The destination can be another user or another computer.
• Reliability: The system should deliver the data to the destiny faithfully. Any unwanted signals (noise) added along with the original data may play havoc!
• Fast:  The system should transmit the data as fast as possible within the technological constraints. In case of audio and video data they must be received in the same order as they are produced without adding any significant delays.

Data Communication model

The figure shows in the block diagram of a typical communication model. The communication model has five sub systems viz., user, transmitter, communication channel, receiver and destiny.

(a) The block diagram of a data communication model

(b) A typical dial-up network

Figure shows a typical dial-up network setup. The data communication equipment (DCE) at the transmitting end converts the digital signals into audio tones (modulation) so that the voice grade telephone lines can be used as guided media during transmission. At the far end the receiving audio tones, they are converted back to digital signals (Demodulation) by the data communication equipment (DCE) and fed to the far end data terminal equipment (DTE).

• User: There will be a source that generates the message and a transducer that converts the message into an electrical signal. The source can be a person in front of a microphone or a computer itself sending a file. The user terminal is known as data terminal equipment (DTE).
• Transmitter: Can be a radio frequency modulator combining the signal coming out of the data equipment terminal. Here the radio frequency is acting as the carrier for the data signal. Or in case of direct digital transmission the transmitter can be Manchester encoder transmitting digital signals directly.
• Communication channel: Can be guided media (twisted pair, coaxial cable, fiber optics) or unguided media (air, water etc). In both the cases communication is in the form of electromagnetic waves. With guided media the electromagnetic waves are guided along a physical path. Unguided media also called wireless the transmitting electromagnetic waves are not guided along with a physical path. They are radiated through air/vacuum/water., etc.
• Receiver: The receiver amplifies the received signals removes any unwanted signals (noise) introduced by the communication channel during propagation of the signal and feeds to the destiny.
• Destiny: The user at the other end finally receives the message through the data terminal equipment stationed at the other side.

Types of communication

 Based on the requirements, the communications can be of different types:

• Point- to-point communication: In this type, communication takes place between two end points. For instance, in the case of voice communication using telephones, there is one calling party and one called party. Hence the communication is point-to-point.
• Point-to-multipoint communication: In this type of communication, there is one sender and multiple recipients. For example, in voice conferencing, one person will be talking but many others can listen. The message from the sender has to be multicast to many others.
• Broadcasting: In a broadcasting system, there is a central location from which information is sent to many recipients, as in the case of audio or video broadcasting. In a broadcasting system, the listeners are passive, and there is no reverse communication path.

• Simplex communication: In simplex communication, communication is possible only in one direction. There is one sender and one receiver; the sender and receiver cannot change roles.

• Half-duplex communication:  Half-duplex communication is possible in both directions between two entities (computers or persons), but one at a time. A walkie-talkie uses this approach. The person who wants to talk presses a talk button on his handset to start talking, and the other person’s handset will be in receiving mode. When the sender finishes,  he terminates it with an over message. The other person can press the talk button and start talking. These types of systems require limited channel bandwidth, so they are low cost systems.

• Full-duplex communication: In a full-duplex communication system, the two parties the caller and the called can communicate simultaneously, as in a telephone system. However, note that the communication system allows simultaneous transmission of data,but when two persons talk simultaneously, there is no effective communication! The ability of the communication system to transport data in both directions defines the system as full duplex. Digital signals cannot be sent in a full-duplex system with a single channel.  If two signals are sent at once, the result will be unreadable because the voltages will add or cancel, resulting in a garbled string of bits.  Full-duplex transmission of digital signals can be accomplished with two channels, one for each direction.  Each station has its receiving apparatus listening on one channel, and its sending capability on the other. One channel can support half-duplex with the understanding that only one station can send at one time.  In order to support half-duplex each station must possess both receiving and transmitting equipment.  Thus each station can transmit and receive.  Note that collisions and corrupted data occur if both stations attempt to transmit at once.  We leave the theory of detecting and preventing simultaneous transmission in half-duplex to discussions of data flow control

Depending on the type of information transmitted, we have voice communication, data communication, fax communication, and video communication systems. When various types of information are clubbed together, we talk of multimedia communications. Even a few years ago, different information media such as voice, data, video, etc. were transmitted separately by using their own respective methods of transmission. With the advent of digital communication and “convergence technologies,” this distinction is slowly disappearing, and multimedia communication is becoming the order of the day.

	A		B

 

                            Simplex A to B only

 

B

A

                      Half-Duplex A to B or B to A

 

                     Full-Duplex A to B and B to A

                Figure: Simplex, Half-Duplex and Full-Duplex.

Modes of transmission

When we talk of data communication we are primarily concerned with serial transmission although other type of transmission does exist. In serial transmission the data is transmitted bit by bit as a stream of 0s and 1s. Protocols are implemented for these types of transmissions so that the communication takes place in a well-defined manner. Protocols are mutually agreed set of rules and are necessary because the format of transmission should be understood by the receiver

 The following key factors have to be observed regarding serial transmission:

• Timing problem: There should be some mechanism to know when the bit has arrived and at what rate the next bit is going to arrive at the serial input terminal of the receiver. We will see this can be accomplished in two ways.
• Error detection:  Provision should be made (during transmission itself) to verify the integrity of the received data. Like parity, checksum bits.
• Error correction:  Ability to correct the data in case of corrupted data reception. 

Communication Protocols

You may be wondering how computers send and receive data across communication links.  The answer is data communication software. It is this software that enables us to communicate with other systems .The data communication software instructs computer systems and devices as to how exactly data is to be transferred from one place to another.  The procedure of data transformation in the form of software is commonly known as protocol. The data transmission software or protocols perform the following functions for the efficient and error free transmission of data.

1. Data sequencing: A long message to be transmitted is broken into smaller packets of fixed size for error free data transmission.

2. Data Routing: It is the process of finding the most efficient route between source and destination before sending the data.

3. Flow control:  All machines are not equally efficient in terms of speed. Hence the flow control regulates the process of sending data between fast sender and slow receiver.

4. Error Control:  Error detecting and recovering is the one of the main functions of communication software.  It ensures that data are transmitted without any error. Many communication channels are subject to channel noise, and thus errors may be introduced during transmission from the source to a receiver. Error detection techniques allow detecting such errors, while error correction enables reconstruction of the original data.

The general definitions of the terms are as follows:

• Error detection is the detection of errors caused by noise or other impairments during transmission from the transmitter to the receiver.
• Error correction is the detection of errors and reconstruction of the original, error-free data.

Error correction may generally be realized in two different ways:

• Automatic repeat request (ARQ) (sometimes also referred to as backward error correction): This is an error control technique whereby an error detection scheme is combined with requests for retransmission of erroneous data. Every block of data received is checked using the error detection code used, and if the check fails, retransmission of the data is requested – this may be done repeatedly, until the data can be verified.
• Forward error correction (FEC): The sender encodes the data using an error-correcting code (ECC) prior to transmission. The additional information (redundancy) added by the code is used by the receiver to recover the original data. In general, the reconstructed data is what is deemed the "most likely" original data.

Digital and Analog Transmission

Data is transmitted from one point to another point by means of electrical signals that may be in digital and analog form. So one should know the fundamental difference between analog and digital signals. In analog signal the transmission power varies over a continuous range with respect to sound, light and radio waves. On the other hand, a digital signal may assume only discrete set of values within a given range. (See figures given below) Examples are computer and computer related equipment. Analog signal is measured in Volts and its frequency is in Hertz (Hz).A digital signal is a sequence of voltage represented in binary form. When digital data are to be sent over an analog form the digital signal must be converted to analog form. So the technique by which a digital signal is converted to analog form is known as modulation. And the reverse process, that is the conversion of analog signal to its digital form, is known as demodulation. The device, which converts digital signal into analog, and the reverse, is known as modem.

Figure: Analog Signal

Figure: Digital Signal

Asynchronous Transmission

In asynchronous transmission data is transferred character by character and each character (frame by frame i.e. each character is an asynchronous frame in asynchronous transmission) and can be 5 to 8 bits long. The term “Asynchronous” means it is asynchronous at frame level. The bits are still synchronized at bit level during reception.

Figure: Asynchronous data format

• In a steady stream, interval between characters is uniform (length of stop element can be 1,1.5 or 2 stop bits - as programmed earlier)
• In idle state, receiver looks for transition 1 to 0 (start signal)
• Then samples next five, seven or eight intervals (as programmed earlier) Timing only needs maintaining within each frame (bit level).
• Looks for parity (if programmed earlier).
• Then looks for next 1 to 0 for next frame .
• Simple.
• Cheap. Minimum hardware & software requirement to implement.
• Overhead of 2 or 3 bits per frame (~20%).
• Good for data with large gaps in between each frame (keyboard, low speed data).

Synchronous Transmission

 In Synchronous transmission a block of data in the form of bits stream is transferred without starts / stop bits. The block can be of any arbitrary length. In order to establish synchronization with remote computer the transmitter transmits synch pulses initially. When the receiver locks to the transmitter’s clock frequency a block of data gets transmitted. See figure.

The Characteristics are as follows

• Block of data transmitted without start or stop bits

• Initially synch pulses are transmitted (Clocks must be synchronized).
• Can use separate clock line (In that case synch pulses are not needed!)
• Good over short distances
• Subject to impairments
• Embed clock signal in data (Manchester encoding)
• Carrier frequency (analog) is used
• Need to indicate start and end of block
• Use preamble and post amble (to leave sufficient space between blocks)
• More efficient (lower overhead) than asynchronous transmission.

Figure:  The synchronous frame format

Multiplexing

By Multiplexing different message signals can share a single transmission media (The media can be guided or unguided). All they need is they should either differ in their frequency slot or wavelength slot or in time slot.

Frequency domain multiplexing (FDM)

          In this each message signal is modulated by different radio frequency signals called rf carriers. At the receiving end filters are used to separate the individual message signals. Then they are demodulated (removing the rf carrier) to retrieve back the original messages.

Figure: Frequency domain multiplexing

The Radio /TV broadcasting are the best examples for frequency domain multiplexing. Several individual stations broadcast their programs in their own allotted frequency band sharing the same unguided media. The receiver tunes his set according to his choice. The cable TV network is another example of Frequency domain multiplexing employing guided media.

Wavelength division multiplexing (WDM)

Wavelength division multiplexing is a type of FDM scheme used in fiber optical communications where various wavelengths of infrared light are combined over strands of fiber. Optical communication with few exceptions are digital since light transmitters and receivers are usually poorly suited for analog modulation.

Figure: A Typical wavelength division multiplexer

Time domain multiplexing (TDM)

 A type of multiplexing where two or more channels of information are transmitted over the same media by allocating a different time interval ("slot" or "slice") for the transmission of each channel. The channels take turns to use the media. Some kind of periodic synchronizing signal or distinguishing identifier is usually required so that the receiver can tell which channel is which. 

 A typical practical setup combines a set of low-bit-rate streams, each with a fixed and pre-defined bit rate, into a single high-speed bit stream that can be transmitted over a single channel.

 The main reason to use TDM is to take advantage of existing transmission lines. It would be very expensive if each low-bit-rate stream were assigned a costly physical channel (say, an entire fiber optic line) that extended over a long distance.

Figure:  Time division multiplexing.

Choose the following

1.              Telephone systems may be classified as:

a)    Duplex and asymmetrical.                            b) Duplex and asymmetrical.

        c)   Duplex and symmetrical.                               d) Simplex and asymmetrical.

2.                      Asynchronous transmission may be defined as:

a)      Communication where the receiver clock must be in exact synchronism with that of the transmitter.

b)      Communication where receiver will operate satisfactorily, even if its clock frequency is appreciably different to that of the transmitter.

c)       Communication where the receiver clock must be in approximate synchronism with that of the transmitter.

d)      None of these

3.                      Synchronous transmission may be defined as:

a)      Communication where the receiver will operate satisfactorily, even if its clock frequency is appreciably different to that of the transmitter.

b)      Communication where the receiver clock must be in approximate synchronism with that of the transmitter.

c)       Communication where the receiver clock is arranged to be in exact synchronism with that of the receiver.

4.              __________ is the process by which information from a source is converted into symbols to be communicated. 

a)    Encoding                 b)decoding              c)encryption            d)decryption

5.              ___________ is the reverse process, converting these code symbols back into information understandable by a receiver.

a)    Encoding                 b)decoding              c)encryption            d)decryption

6.              ____________at the transmitting end converts the digital signals into audio tones

a)    Data communication equipment                b) Data transfer equipment

c)  Data transmission equipment                   d) Data collection equipment

True or false for the following statement

1. The basic requirements for working of a communication system are sender, medium and receiver.
2. In full duplex the communication channel issued in both directions at the same time.

Answer the following

1. Define data communication. How it is different from other types of communication?
2. Draw the block diagram of typical data communication model and explain its constituents.
3. Enumerate different types of communication. Site examples for each of them?
4. Discuss in detail about multiplexing.
5. Why Protocols are needed in data communication?
6. What is communication protocol?
7. What is the difference between asynchronous and synchronous transmission?
8. In a city the following traffic rules are implemented for reducing traffic block. In road A the vehicles can go from East to West. In road B the vehicles can pass only in one direction at a time. In road C, the vehicles are free to move in both directions at the same time. How do you correlate the above type of traffic system with modes of data communication?
9. What is meant by wave division multiplexing?
10. What is meant by time domain multiplexing?
11. What is frequency division multiplexing?
12. What are the advantages of Asynchronous transmission?
13. What are the advantages of Synchronous transmission?
14. What is the difference between digital and analog transmission?
15. Explain different ways of realizing error correction?
16. Differentiate error correction and error detection?
17. What are the functions of communication protocols for the efficient and error free transmission of data?
18. What are the fundamental concepts of data communication?

computer model questions

KERALA STATE RUTRONIX
Fundamentals of Computer & Operating System
(CTTC, CPPTTC, WPDEO, CWPDE, PDDTP, PDCFA, DCA, DOA)
A1
Question Code
Time : 2 hours Maximum Marks : 100
Note: Write the answers for Questions from 1 to 35 in the MCQ answer sheet
Part- I Choose the most appropriate answer (10 x 1 Mark = 10 Marks)
1) The working memory of a computer is called ……………….
a) Ram b) Rom c) Hard Disk d) Cache
2) Laser printer is a type of ………………. printer.
a) Impact b) Non Impact c) Line d) Character
3) PDF is widely used for exchanging ……………….
a) Documents b) Music files c) Database files d) None of These
4) Firefox is a well known ……………….
a) Interface b) Web Browser c) Antivirus d) None of These
5) A private network inside a company or organization is called ……………….
a) Telnet b) Extranet c) Internet d) Intranet
6) Rebooting while the computer system is on is known as ………………. booting.
a) Cold b) Warm c) Hibernate d) None of these
7) ………………. is a valid LINUX command.
a) Rat b) Mouse c) Cat d) Cls
8) Which of the following storage is volatile?
a) Flash memory b) DVD c) RAM d) CD- ROM
9) Third generation computers used ……………….
a) Vacuum tubes b) Transistor c) Integrated circuits d) Microprocessors
10) The hardware device used to input text or images into the computer is ……………….
a) Light pen b) Joystick c) Track ball d) Scanner
Part- II Fill in the blanks (15 x 1 Mark = 15 Marks)
11) The short cut key used for undo is ……………….
12) ………………. function key is normally used for help.
13) ………………. topology combines the characteristics of bus and star topologies.
14) ………………. is a display that can detect the presence and location of a touch within the display area.
15) 1's complement of 10101101 is ……………….
16) In a flowchart, the symbol used to represent calculation is ……………….
17) A ………………. is a set of rules that governs the communication between computers on a network.
18) Graphical representation of algorithm is called ……………….
19) Accessing information from a website is known as ……………….
20) A ………………. is the smallest element of information used by a computer.
21) The unique address associated with each page on the web is ……………….
22) ………………. is a humanoid robot created by Honda Motor Company.
A1- 7000 : January 2013- Page 1 of 2 P.T.O
23) Programs stored in ROM are called ……………….
24) USB is a ………………. Pin connector.
25) A ………………. is a group of 4 bits.
26) Track ball is also known as game controller.
27) LINUX is case sensitive.
28) The process of removing errors in a program is called debugging.
29) Magnetic and optical devices are generally volatile.
30) Pentium 4 is the name of microprocessor created by intel.
31) Logical error can be trapped by the compiler.
32) Bluetooth is a wireless personal area network.
33) Visual Basic is an example of low level language.
34) Pen drive is a type of flash memory.
35) MS-DOS is an example of command user interface.
Part - IV Expand the following (10 x 1 Mark = 10 Marks)
36) MICR
37) LASER
38) EEPROM
39) DVD
40) USB
41) FTP
42) UPS
43) ISP
44) MODEM
45) OMR
(Part V, Part VI F¶nhbpsS D¯c§Ä aebmf¯nepw FgpXmw)
4 6 ) C o m p i le r, Interpreter and Assembler.
47) ROM and its various types.
48) Computer storage devices.
49) Types of Network.
50) Compare CRT and LCD monitors.
51) Five pointing devices.
52) Extranet and Intranet.
53) Types of Operating System.
54) Five internal DOS commands with examples.
55) Application Software.
56) Network Topology.
57) Symbols used in flowcharting.
58) Types of Printers.
59) Communication Protocols.
Page 2 of 2
Part-VI Explain the following (Any Two) (2 x 10 Marks = 20 Marks)
P a r t - V Explain the f o llowing (Any Seven) (7 x 5 Marks = 35 Marks)
Part - III State whether true or false (10 x 1 Mark = 10 Marks)

COMPUTER COURSE FEE DETAILS

cybotech computers

SHORT CUTS

More than 100 Keyboard Shortcuts must read
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Keyboard Shorcuts (Microsoft Windows)
1. CTRL+C (Copy)
2. CTRL+X (Cut)
3. CTRL+V (Paste)
4. CTRL+Z (Undo)
5. DELETE (Delete)
6. SHIFT+DELETE (Delete the selected item permanently without placing the item in the Recycle Bin)
7. CTRL while dragging an item (Copy the selected item)
8. CTRL+SHIFT while dragging an item (Create a shortcut to the selected item)
9. F2 key (Rename the selected item)
10. CTRL+RIGHT ARROW (Move the insertion point to the beginning of the next word)
11. CTRL+LEFT ARROW (Move the insertion point to the beginning of the previous word)
12. CTRL+DOWN ARROW (Move the insertion point to the beginning of the next paragraph)
13. CTRL+UP ARROW (Move the insertion point to the beginning of the previous paragraph)
14. CTRL+SHIFT with any of the arrow keys (Highlight a block of text)
SHIFT with any of the arrow keys (Select more than one item in a window or on the desktop, or select text in a document)
15. CTRL+A (Select all)
16. F3 key (Search for a file or a folder)
17. ALT+ENTER (View the properties for the selected item)
18. ALT+F4 (Close the active item, or quit the active program)
19. ALT+ENTER (Display the properties of the selected object)
20. ALT+SPACEBAR (Open the shortcut menu for the active window)
21. CTRL+F4 (Close the active document in programs that enable you to have multiple documents opensimultaneou sly)
22. ALT+TAB (Switch between the open items)
23. ALT+ESC (Cycle through items in the order that they had been opened)
24. F6 key (Cycle through the screen elements in a window or on the desktop)
25. F4 key (Display the Address bar list in My Computer or Windows Explorer)
26. SHIFT+F10 (Display the shortcut menu for the selected item)
27. ALT+SPACEBAR (Display the System menu for the active window)
28. CTRL+ESC (Display the Start menu)
29. ALT+Underlined letter in a menu name (Display the corresponding menu) Underlined letter in a command name on an open menu (Perform the corresponding command)
30. F10 key (Activate the menu bar in the active program)
31. RIGHT ARROW (Open the next menu to the right, or open a submenu)
32. LEFT ARROW (Open the next menu to the left, or close a submenu)
33. F5 key (Update the active window)
34. BACKSPACE (View the folder onelevel up in My Computer or Windows Explorer)
35. ESC (Cancel the current task)
36. SHIFT when you insert a CD-ROMinto the CD-ROM drive (Prevent the CD-ROM from automatically playing)

Dialog Box - Keyboard Shortcuts
1. CTRL+TAB (Move forward through the tabs)
2. CTRL+SHIFT+TAB (Move backward through the tabs)
3. TAB (Move forward through the options)
4. SHIFT+TAB (Move backward through the options)
5. ALT+Underlined letter (Perform the corresponding command or select the corresponding option)
6. ENTER (Perform the command for the active option or button)
7. SPACEBAR (Select or clear the check box if the active option is a check box)
8. Arrow keys (Select a button if the active option is a group of option buttons)
9. F1 key (Display Help)
10. F4 key (Display the items in the active list)
11. BACKSPACE (Open a folder one level up if a folder is selected in the Save As or Open dialog box)

Microsoft Natural Keyboard Shortcuts
1. Windows Logo (Display or hide the Start menu)
2. Windows Logo+BREAK (Display the System Properties dialog box)
3. Windows Logo+D (Display the desktop)
4. Windows Logo+M (Minimize all of the windows)
5. Windows Logo+SHIFT+M (Restorethe minimized windows)
6. Windows Logo+E (Open My Computer)
7. Windows Logo+F (Search for a file or a folder)
8. CTRL+Windows Logo+F (Search for computers)
9. Windows Logo+F1 (Display Windows Help)
10. Windows Logo+ L (Lock the keyboard)
11. Windows Logo+R (Open the Run dialog box)
12. Windows Logo+U (Open Utility Manager)
13. Accessibility Keyboard Shortcuts
14. Right SHIFT for eight seconds (Switch FilterKeys either on or off)
15. Left ALT+left SHIFT+PRINT SCREEN (Switch High Contrast either on or off)
16. Left ALT+left SHIFT+NUM LOCK (Switch the MouseKeys either on or off)
17. SHIFT five times (Switch the StickyKeys either on or off)
18. NUM LOCK for five seconds (Switch the ToggleKeys either on or off)
19. Windows Logo +U (Open Utility Manager)
20. Windows Explorer Keyboard Shortcuts
21. END (Display the bottom of the active window)
22. HOME (Display the top of the active window)
23. NUM LOCK+Asterisk sign (*) (Display all of the subfolders that are under the selected folder)
24. NUM LOCK+Plus sign (+) (Display the contents of the selected folder)

MMC COnsole Windows Shortcut keys

1. SHIFT+F10 (Display the Action shortcut menu for the selected item)
2. F1 key (Open the Help topic, if any, for the selected item)
3. F5 key (Update the content of all console windows)
4. CTRL+F10 (Maximize the active console window)
5. CTRL+F5 (Restore the active console window)
6. ALT+ENTER (Display the Properties dialog box, if any, for theselected item)
7. F2 key (Rename the selected item)
8. CTRL+F4 (Close the active console window. When a console has only one console window, this shortcut closes the console)

Remote Desktop Connection Navigation
1. CTRL+ALT+END (Open the Microsoft Windows NT Security dialog box)
2. ALT+PAGE UP (Switch between programs from left to right)
3. ALT+PAGE DOWN (Switch between programs from right to left)
4. ALT+INSERT (Cycle through the programs in most recently used order)
5. ALT+HOME (Display the Start menu)
6. CTRL+ALT+BREAK (Switch the client computer between a window and a full screen)
7. ALT+DELETE (Display the Windows menu)
8. CTRL+ALT+Minus sign (-) (Place a snapshot of the active window in the client on the Terminal server clipboard and provide the same functionality as pressing PRINT SCREEN on a local computer.)
9. CTRL+ALT+Plus sign (+) (Place asnapshot of the entire client window area on the Terminal server clipboardand provide the same functionality aspressing ALT+PRINT SCREEN on a local computer.)

Microsoft Internet Explorer Keyboard Shortcuts
1. CTRL+B (Open the Organize Favorites dialog box)
2. CTRL+E (Open the Search bar)
3. CTRL+F (Start the Find utility)
4. CTRL+H (Open the History bar)
5. CTRL+I (Open the Favorites bar)
6. CTRL+L (Open the Open dialog box)
7. CTRL+N (Start another instance of the browser with the same Web address)
8. CTRL+O (Open the Open dialog box,the same as CTRL+L)
9. CTRL+P (Open the Print dialog box)
10. CTRL+R (Update the current Web )

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abacus

vacation computer courses

 

 

COMPUTER BASE

DIGITAL SUMMER CAMP

PUBLISHED BY

 RESEARCH TEAM

 SDCT, THIRUVANANTHAPURAM

COMPUTER

Computer is an electronic device that can perform a variety of operations in accordance with a set of instructions called program.

Features of computer

1.      Speed

2.      Storage capacity

3.      Accuracy

4.      Reliability

5.      Versatility

Parts of a Computer

            Basically a computer has three parts, they are:

1.      Input Unit

2.      CPU (Central Processing Unit)

3.      Output Unit

Block diagram of a Digital Computer

Input Unit

            It is the unit meant to receive the data and instruction contain in program. In other words it is the unit through which the programmer communicates with the computer.

Eg: Keyboard, Mouse, Scanner, MICR, OCR, etc…

CPU (Central Processing Unit

            It is the   brain of the computer that actually under stand and executes all the instructions. The CPU comprises three distinct parts, namely Memory Unit, ALU (Arithmetic & Logic Unit and Control Unit.

ALU (Arithmetic & Logic Unit)

This is the place where actual execution of the instruction takes place during the data processing. The ALU is capable of performing the basic arithmetic operations such as addition, subtraction, multiplication, division and some of the logical operations.

Memory Unit

            Memory Unit is the section where all data, program and results are stored. The memory of the computer is classified into Primary Memory and Secondary Memory.

Primary Memory

            It is also called computers main memory. All data information which are to be processed by the computer, are kept ready in this memory. The results obtained after processing in the arithmetic and logic unit are also stored in main memory.

                        Commonly used primary storage devices are:

1.      RAM –Random Access Memory

2.      ROM – Read Only Memory

Secondary Memory

            The programs and data which require any further use are stored in a Secondary Memory. Recording, erasing and rerecording for a number of times are possible in an auxiliary storage.

            Commonly used Secondary Storage devices are:

1.      Floppy Disk

2.      Hard Disk

3.      Magnetic Disk

4.      CD ROM

Output Unit

           It is the unit meant to display the result of computation from the memory. Some of the Out put devices produce only a temporary copy of a result (like the monitor), while some others produce a permanent copy (like the printer)

                         

MICROSOFT WORD

                        Microsoft Word is a word processing package. This refers to create documents, store and manipulate them for editing or formatting

Elements of MS Word

Title bar- Display the ms-word title with file name.

Menu bar- Display the menus and pull down menus of word.

Standard tool bar- A bar with buttons that performs some of the most common task in word such as new, open save, print….etc

Formatting tool bar- A bar with buttons and options used to apply commonly used to format such as bold italic, font, size, etc

Work area – Typing areas of Ms Word.

Status bar- The bar at the bottom of word window that display information about the current status document

Menus of word

            File, Edit, View, Insert, Format, Table, Windows, Help

File menu commands

New – Create a blank document.

Open – opens an Existing document.

Close – Close the active document.

Save – Saves the active document.

Saves – Saves the active document with different names.

Page setup- Change margin and size.

Print preview – Show a document look when you print it.

Print – Controls how document is printed.

Edit Menu Commands

   

Undo – Reverses one or more changes made in a document.

Redo – Repeat the action cancelled with the undo operation.

Cut – Removes a selected text from the document and place it in the clipboard.

Copy – Copies a selected text to the clipboard.

Paste – Insert a copy of clipboard contents at the selected place.

Clear – Deletes a selected text.

Select All – Selecting the document of entire document.

Find (ctrl+f) - Searches for specified text from document

Replace (ctrl+f)-Searching a particular text and replacing it with another word.

Go to (ctrl+f) - Finding a page, lines, Book mark etc

View Menu Commands

Normal- Displays document in a simple view

Outline - Displays the heading levels with paragraph levels.

Page layout View – A WYSWYG (What you see is what you get) view that allows us to see what the page will look when printed.

Full Screen- Hides all screen elements and display the contents of documents in full screen.

Tool Bar – Displays or hides the entire tool bars in word.

Ruler- Displays or hides the vertical and horizontal ruler lines

Header and Footer- Adds special text or graphics words repeats top of every page (header) and bottom of every page (footer).

Zoom-

Insert Menu Commands

Break- Insert a page break, column break, and sections break at the insertion point.

Page Number- Inserts page numbers with in a document.

Step:

    

1.      Insert –Page Number

2.      Select the  location and Position

3.      Click ok button

Date and Time- Insert the date and time in the different format.

Symbol- Insert special character to the document.

Foot Note- Inserts a footnote or endnote for a selected text.

     Foot note- Foot notes are placed at the end of the page

     End note- End notes are placed at the end of the document

Picture- Inserts a graphic or picture created in another application.

Object- Inserts a drawing object from another application.

Hyperlink- To link a word or picture with a file.

 Step

1.      Select the text or picture to hyper link.

2.      Insert – hyper link.

3.      Click Browse for file button.

4.      Select the file we want to link and ok.

Format Menu Commands

Font – font tab

1.      Font – Use to select a font name.

2.      Font style – Select a style.

3.      Size – Selecting a size

4.      Under line – Select the type of under line.

5.      Color – select the color of selected text.

6.      Effect – Select a combination of effect.

Paragraph – Controls the appearance of paragraph by indentation and text below.

            Indents – left and right boundary of selected text.

Types of indents

1.      Left indent

2.      Right indent

3.      first line indent

4.      hanging indent

Alignment

1.      Left alignment

                Aligns the text at the left indent.

2.      Right alignment

                   Align selected text at the right indent.

3.      Centered alignment

                     Centers selected text between the left and right indents.

4.      Justified alignment

                   Expands spaces in to lines to align text evently between the left and right indent

Boarders and Shading

           Add boarders and shading to selected paragraphs, table, cell and frames.

Columns

         Change the number of columns in a selected document.

Change case

          Change the selected characters to upper case, lower case, etc.

1.      Sentence case – Capitalizes the first letter of first word in a sentence.

2.      Upper case – Changes to the selected text to upper case.

3.      Lower case – Changes to the selected to lower case.

4.      Toggle case – Changes uppercase letters to lower case and lower case letter to uppercase.

5.      Title case - Capitalize the first letter of each word in the selections.

Bullets and Numbering

Formats bullets and styles with in a list.

 Back ground

                  This option is used to change the background color.

Style

           This command is used to create modify or apply a style for a selected text.

Tools Menu Commands

Spelling- Checks the spelling in the active document

Options- 

1. Change – Select word form suggestions list and replaces it in the position of original word.
2. Ignore -   Does not correct the spelling of the current  word.

Grammar

     Checks the documents for possible grammar and style errors and displays suggestions for correcting them.

Auto correct

    Customizes the settings used to correct text automatically as you type.

Protect Document

     Allow temporary protection for a document.

Macro

    A Macro is a series of keystrokes and mouse links that can be called with the simple click of the mouse.

Table Menu

Insert table: Insert a table with number of rows and columns with a specified column width.

Delete cells: Delete the selected cells in a table

Split cells: Split a cell horizontally in to multiple cells

Merge cells: Combine the contents of adjacent cell into a single cell.

Select table: Select the entire table. Short cut Alt+5

Sort: Arranges the information of selected rows alphabetically, numerically or by data

Split table: Divides a table into two parts and inserts a paragraph mark above the splited row

New window of Microsoft Word 2007

MICROSOFT EXCEL

It is a standard Spread Sheet Software package developed by Microsoft Corporation, USA. It is used extensively in preparing budgetary reports, Profit and Loss accounts etc. 

Work Book   

            A blank document in MS Excel Window is called an Excel Workbook. A work book is a large are consisting of 65,536 rows and 256 columns. The intersection of each row and column is called a cell.

Formula Bar

            The formula bar is located just below the formatting toolbar. It shows the address of the active cell, name of the place, where the cell pointer is located and the contents of the active cell.

Copying and moving worksheets

     One or more selected worksheets can be copied within and between workbooks.

Inserting an Deleting worksheets

     Work book can be expanded or contracted by inserting or deleting work sheets.

*Choose Insert – Work sheet from the menu bar to insert a new worksheet or right                               click on one of the selected sheet tabs and select insert from the shortcut menu.

*Choose Edit- Delete sheet from the menu bar or right click on the sheet and choose the delete from the shortcut menu.

Columns width and Rows Height

              If the data which is entered into the cell is bigger than the width of the column, It is partially visible. The column width can be adjusted by the following steps.

              *Select the column

               *The column option is selected from the format menu.

                *Click on the width …. option. A dialog is displayed.

                *type the required of the column in the text box column width.

         Similarly the rows height can also be adjusted by selecting the rows….option from the Format menu.

Auto Format

The predesigned formats allow you to apply a standard format to all or part of a worksheet.

*Select the portion of the worksheet you want to auto format.

*Choose format –Auto format from the menu bar to open the Auto format dialog box.

 * Choose any format which you want

* Click the options buttons to show format to apply and deselect any option which you do not want to show click OK.

Conditional Formatting

Using Conditional formatting formats can be applied to selected cells based on the condition.

Formula

            In a spreadsheet one of the powerful feature is of formulas. Formulas can be used to perform calculations involving addition, substration, division and multiplication. In excel formulas begins with an equal sign.

Functions

            Functions are built in special programs which accept data, known as arguments, and return a value after performing calculations on the data. The different types of functions are statistical function, mathematical function, text functions etc.

New window of Microsoft Excel 2007

MICROSOFT POWER POINT

                        Power point is used to create Professional quality presentations. It allows as creating the presentations with text pictures, sound and animations.

Power point views

1. Slide view
2. Outline View
3. Slide sorter view

Slide Transition

            Transition control the way in which, each slide will appear as its opens on the slide show screen.

To open Slide Transition dialog box Choose Slide show à Slide Transition.

Animation

            We can change the order in which objects enter the slide and the manner in which each object on the slide.

            To changes the settings for an object.

                        Choose Slide Show à Custom Animation

                        In custom animation we can set

                                    - The timing

                                    - Control when sounds and text items are introduced.

                                    - Determine how we want charts animated

- Set play settings to control when and if an object is animated on   the slide.

Running a Slide Show

                        To run a slide show

                                    Click Slide Showà View Show

New window of Microsoft Powerpoint  2007

                                   

INTERNET

                        Internet is a world wide network of computers. It consists of millions of computers connected to each other and capable of exchanging data and information by using communication links such as telephone lines fiber optics satellite and other Medias.

WWW – World Wide Web

                        World Wide Web is the collection of all types of information stored in millions of computers connected to the internet.

E-Mail

            Electronic mail or E-mail is a simple tool for sending and receiving brief text messages between individuals or among larger audiences.

GIMP

GIMPis an acronym for GNU Image Manipulation Program. It is a freely distributed program for such tasks as photo retouching, image composition and image authoring.

Starting GIMP

                        Start à Programs à GIMP

                                    Now we get a small window, containing many tool and options on screen.

            To create a new file,

                                    Click new from the file menu, we get a dialog box, give the width, height and resolution of the file and then click ok.

Tools in GIMP

Rectangular selection tool

            Elliptical selection tool

            Hand- drawn selection tool

            Bezier curves selection tool

            Image shapes selection tool

            Selection Tool

            Pick color tool

            Zoom in and out tool

            Distance and Angular measurement tool

            Move Layer and selection tool

            Cut & Resize tool

            Rotation tool

            Shearing tool

            Change the mode of vision tool

To turn the layer tool

Text tool

Fill with color or pattern

            Fill with color gradient

            Pencil tool

            Brush tool

            Eraser tool

            Spray colors

            Pen tool

            Pattern tool

             

Change background color

            Click Black rectangle on the tool box

            We will get a dialog box , Select the required color