TyroCity: Computer Notes

Number System

TyroCity.com — Sat, 12 Jul 2014 05:41:42 +0000

Conversion Techniques

1. Decimal to
a. Binary

/2 (Integer Part)
*2 (Decimal Part)

b. Octal

/8 (Integer Part)
*8 (Decimal Part)

c. Hexadecimal

/16 (Integer Part)
*16 (Decimal Part)

2. Binary to
a. Octal

Table (3-bit)

b. Decimal

*2n For eg. (1011)2 =1*23+0*22 +1*21+1*20

c. Hexadecimal

Table (4-bit)

3. Octal to
a. Binary

Table (3-bit)

b. Decimal

*8n For eg. (2341)8 =2*83+3*82 +4*81+1*80

c. Hexadecimal

Construct table of:
- Octal-Binary (3Bit)
- Binary-hexadecimal (4Bit)

4. Hexadecimal to

a. Binary

Table (4-bit)

b. Octal

Construct table of:
- Hexa-Binary (4Bit)
- Binary-Octal (3Bit)

c. Decimal

*16n For eg. (12A8)2 =1*163+2*162 +10*161+8*160

1’s and 2’s Complement

9’s and 10’s Complement

Computer XI Questions

TyroCity.com — Sun, 18 Aug 2013 05:41:42 +0000

Questions

Model Question for Computer Science Class 11

TyroCity.com — Sun, 18 Aug 2013 05:41:42 +0000

GRADE : 11
FOR : 2070
Time : 3hrs
F.M. : 75
P.M : 27

Group A (Long Answer Question)
Attempt ALL the questions. [3 × 10 = 30]

Draw a well-labeled diagram of typical architecture of a computer system and explain the main function of Control Unit and ALU. [4+3+3] 2.a. What is an operating system ? Explain any three function of an operating system. [1 + 6] 2.b. The “WiMP” environment is much more user-friendly, why ?

OR
2.a. What is cell addressing and explain different types of cell addressing used in spreadsheet. [5]
2.b. Write a tag to design your personal web page to link photo family, background and banner page using frame. [5]

3.a. Define flowchart and pseudocode. Explain their significance in programming. [5]

3.b. Write a pseudocode to accept any three numbers and output the largest among them. [5]

Group B (Short Answer Questions)
Attempt any NINE questions. [9 × 5 = 45]

Classify the computers according to their generation based on the technology used. [5]
Differentiate between analogue and digital computer, explain with examples. [5]
What do you mean by number system? Why do digital computers use binary numbers for their operation ? [2 + 3]
Convert these numbers. [5]
- (126)10 = (?) 2
- (11011)2 = (?) 10
- (57)8 = (?) 2
Perform following operations.
- 1011 – 1001
- 1110 + 1110
State the Demorgan’s theorem and verify it. [5]
What are logic gates? Construct the truth table of NOR operation. [5]
Write short notes on (any two) : [5]
- IDE
- SCSI
- Wave Camera
What are uses of internet ? Write any five search engine name. [5]
Differentiate between System Software and Application Software with examples. [5]
What are DPT features in MS-Words? Write three features of Presentation Packages. [2 + 3]
Write an algorithm and flowchart to print the word “Hello” ten times using “while loop” [5]

Computer Science Grade-11 2069

TyroCity.com — Sun, 18 Aug 2013 05:41:42 +0000

Candidates are required to give their answers in their own words as far as practicable. The figures in the margin indicate full marks.

Full Marks:- 75
Pass Marks:- 27
Time:- 3hrs.

Group A
Long answer questions

Attempt any three questions. 3×10=30

What is an operating system? Explain the functions of operating system.
What is memory in the computer system? Explain primary and secondary memory.
What is programming? Differentiate between compiler and interpreter.
What is Boolean algebra? Describe AND gate, OR gate, NOT gate and NAND gate symbol and Truth Table.

Group B
Short answer questions
Attempt any nine questions. 9×5=45

Why computer is known as versatile and diligent device? Explain.
What is mobile computing? Explain. Or Differentiate between analog and digital computer.
Convert (110111101)2 binary number into octal number.
What is BUS in terms of computer architecture? Explain.
Differentiate between Impact and Non-impact printers with examples.
What is internet? Write down the uses of internet. Or Explain the features of word processor.
What is web page? List the features of web page. Or Write down the advantages and disadvantages of DBMS. (Old)
What is CPU? Write down the functions of CPU.
Explain the types of programming errors with examples.
Subtract (1100)2 from (1111)2 using 1st and 2nd complement method.
Write short notes on:
- Modem
- Trackball

Laser Printer

Computer 12 Notes — Sun, 08 Apr 2012 05:41:42 +0000

It is non-impact type page printer. It uses powder ink (toner) for printing. It is expensive to buy but its operating cost is low. So, it is appropriate for large volume printing. Multi-colored laser printer is larger in size and they are slower and expensive. It can print about 30 pages per minute.

Merits:

It is not noisy and is faster than impact printer.
It can be both single and multi-colored.
Its operating cost is low.
It can print both text and images.
Its printing quality is better than impact printer.

Demerits:

It is expensive to buy.
It can’t print multiple copies at the same time.
It is not appropriate for continuous printing.

Internet

Computer 11 Notes — Sun, 08 Apr 2012 05:41:42 +0000

Internet is the connection of millions of computers spread all over the world. It is the world largest computer network. It is the network of networks.

It is a public network so it is not owned by a particular user organization or government. However, it is controlled by internet authority.
Internet is initiated by US army. It was used for their internal communication but later, it become popular and used all over the world.

Uses of internet

Online communication: – It is used for online communication.
It is helpful for online business through e-commerce.
It is helpful for video conference.
It is helpful for e-ticketing, online reservation.
It helps to find information about various things.
It is used for entertainment.
It is used for downloading the video files, music files.
It is used for online job.
Advertisement.

Some terms related with Internet are:

1. Browser:-
A browser is internet based application software used to access a webpage. It sends request to the web server and displays the received HTML files in proper format user interact with the internet by using browser.
e.g. Google Chrome, Internet Explorer, Mozilla Firefox, Opera, Netscape, Safari, etc.

2. Search engine:-
It is also internet based application software. It can be used to access the required information or webpage address from the internet. A search engine maintains the record of all the websites and their contents. When the user requests by providing the keywords, it provides a list of websites and their links from its database. Google.com is the most common search engine at present. Other search engine includes bing.com, yahoo.com, altavista.com, webcrawler.com, etc.

3. Messenger service:-
A messenger is also internet based application software. It is used for communication. Such as text chat, audio-video chat, conference call, transmitting data and files, offline messages, etc. Some of the common messengers used are MSM messenger, Yahoo messenger, Google talk, AOL, Skype, etc.

4. Webpage:-
It is the fundamental unit of web. It is used to provide text emails, audio, video to the users. Webpage is developed by using scripting and web based programming language. Webpage are of two types:

Static
Dynamic

A static webpage is developed by using HTML.
Dynamic webpage is developed by using programming language like PHP, ASP, C#, etc along with HTML.

5. Website:-
A website is a location used for storing webpage. User access the webpage by using the website address. For e.g. facebook.com, tyrocity.com, babal.host, etc.

6. Web server:-
Web server is a program required to host webpage so that it can be accessed through the internet. To host webpage, the computer should have web server running, dedicated internet connection and the computer should be running all the time. The common web servers used are IIS (Internet Information Service) and Apache (for Linux based system).

7. URL (Uniform resource locator):-
It is a complete website address which is used to specify domain name, website location, and the protocol used for communication. A complete URL is provided to access a web site.
e.g. https://tyrocity.com, http://www.google.com.np.

8. Domain name system (DNS)
A domain name system is the process of using domain name to access a computer or website such as hotmail.com is a domain name. Domain names are easier to remember and access compared to IP address. However, communication is done through IP address. An IP address is a numerical value such as 192.168.1.1. It is used to identify a particular computer on a network. Since, these IP addresses are difficult to remember, domain names are used in place of IP address. A DNS translates domain name into corresponding IP address. Domain names are classified on the basis of type of organization and the country wise.

Type of organization:-
.com
.org
.edu
.gov
.net
.mil
.biz
.tv

Country wise:-
.np
.in
.sl
.pk
.uk
.au

9. Protocol:-
A protocol is a rule or standard defined to be used by all the components. Network protocol can be defined as the rules used for communication between two or more devices.

Some of the common network protocols used are:-

HTTP ( Hyper Text Transfer Protocol)
FTP (File Transfer Protocol)
HTTPS (Hyper Text Transfer Protocol Secured)
SMTP (Simple Mail Transfer Protocol)
POP (Post Office Protocol)
IMAP (Internet Mail Access Protocol)
IP (Internet Protocol)
TCP (Transmission Control Protocol)
UDP (User Datagram Protocol)
VOIP (Voice Over Internet Protocol)

- HTTP:
It is used for the communication of hypertext document. Webpages are the example of hypertext document. It is developed by using HTML and contains hyperlink.

- FTP:
It is used for the transmission of files like document image, audio, video, software, games, etc.

- HTTPS:
It is used for the transmission of hypertext document by providing higher security. It is mainly used by banking sector, e-commerce, and other electronic payment system where higher security is required. It uses encryption and decryption technique to provide security.

- SMTP, POP & IMAP:
These protocols are used for email communication for sending and receiving emails.

- IP:
It is the most common protocol used in internet to identify a particular system. It is used along with TCP in internet (TCP/IP).

- TCP:
It is connection oriented protocol i.e. connection is maintained throughout communication. It provides reliable transmission so it is slower than UDP. It is the common protocol used in internet for transmission of hypertext documents, files and email message.

- UDP:
It is connectionless protocol. It doesn’t provide reliable transmission but it is faster than TCP. So, UDP is preferred for transmitting real time, multimedia data.

- VOIP:
It is used for transmission of voice signal through internet. It is the cheaper and faster medium of communication mainly for a long distance.

Types of Programming Languages

Computer 11 Notes — Sun, 08 Apr 2012 05:41:42 +0000

There are two types of programming languages, which can be categorized into the following ways:

1. Low level language

Machine language (1GL)
Assembly language (2GL)

2. High level language

Procedural-Oriented language (3GL)
Problem-Oriented language (4GL)
Natural language (5GL)

1. Low level language
This language is the most understandable language used by computer to perform its operations. It can be further categorized into:

- Machine language (1GL)
Machine language consists of strings of binary numbers (i.e. 0s and 1s) and it is the only one language, the processor directly understands. Machine language has an Merits of very fast execution speed and efficient use of primary memory.

Merits:

It is directly understood by the processor so has faster execution time since the programs written in this language need not to be translated.
It doesn’t need larger memory.

Demerits:

It is very difficult to program using 1GL since all the instructions are to be represented by 0s and 1s.
Use of this language makes programming time consuming.
It is difficult to find error and to debug.
It can be used by experts only.

- Assembly language
Assembly language is also known as low-level language because to design a program programmer requires detailed knowledge of hardware specification. This language uses mnemonics code (symbolic operation code like ‘ADD’ for addition) in place of 0s and 1s. The program is converted into machine code by assembler. The resulting program is referred to as an object code.

Merits:

It is makes programming easier than 1GL since it uses mnemonics code for programming. Eg: ADD for addition, SUB for subtraction, DIV for division, etc.
It makes programming process faster.
Error can be identified much easily compared to 1GL.
It is easier to debug than machine language.

Demerits:

Programs written in this language is not directly understandable by computer so translators should be used.
It is hardware dependent language so programmers are forced to think in terms of computer’s architecture rather than to the problem being solved.
Being machine dependent language, programs written in this language are very less or not protable.
Programmers must know its mnemonics codes to perform any task.

2. High level language
Instructions of this language closely resembles to human language or English like words. It uses mathematical notations to perform the task. The high level language is easier to learn. It requires less time to write and is easier to maintain the errors. The high level language is converted into machine language by one of the two different languages translator programs; interpreter or compiler.

High level language can be further categorized as:

Procedural-Oriented language (3GL) Procedural Programming is a methodology for modeling the problem being solved, by determining the steps and the order of those steps that must be followed in order to reach a desired outcome or specific program state. These languages are designed to express the logic and the procedure of a problem to be solved. It includes languages such as Pascal, COBOL, C, FORTAN, etc.

Merits:

Because of their flexibility, procedural languages are able to solve a variety of problems.
Programmer does not need to think in term of computer architecture which makes them focused on the problem.
Programs written in this language are portable.

Demerits:

It is easier but needs higher processor and larger memory.
It needs to be translated therefore its execution time is more.

- Problem-Oriented language (4GL)
It allows the users to specify what the output should be, without describing all the details of how the data should be manipulated to produce the result. This is one step ahead from 3GL. These are result oriented and include database query language.
Eg: Visual Basic, C#, PHP, etc.

The objectives of 4GL are to:
Increase the speed of developing programs.
Minimize user’s effort to botain information from computer.
Reduce errors while writing programs.

Merits:

Programmer need not to think about the procedure of the program. So, programming is much easier.

Demerits:

It is easier but needs higher processor and larger memory.
It needs to be translated therefore its execution time is more.

- Natural language (5GL)
Natural language are stil in developing stage where we could write statrments that would look like normal sentences.

Merits:

Easy to program.
Since, the program uses normal sentences, they are easy to understand.
The programs designed using 5GL will have artificial intelligence (AI).
The programs would be much more interactive and interesting.

Demerits:

It is slower than previous generation language as it should be completely translated into binary code which is a tedious task.
Highly advanced and expensive electronic devices are required to run programs developed in 5GL. Therefore, it is an expensive approach.

These are the different types of programming languages with their merits and demerits.

Ink Jet Printer

Computer 12 Notes — Sun, 08 Apr 2012 05:41:42 +0000

It is non impact type character printer. It uses liquid ink for printing. It can be single or multi-colored. Multi-colored ink jet printer can use either RGB colors or CYMK (cyan, yellow, magenta, black). This printer uses dot-matrix approach for printing i.e. a dot is formed by spraying liquid ink. Series of dots are used to print characters and images. It is cheaper to buy but its operating cost is expensive due to expensive ink. So, it is appropriate only for low volume printing.

Merits:

It is not noisy and is faster than impact printers.
It can be both single and multi-colored.
It is cheaper to buy.
It can print both text and images.
Its printing quality is better than impact printers.

De-merits:

Its operating cost is high.
It is appropriate for low volume printing only.
It can’t produce multiple copies at the same time.
It is not appropriate for continuous printing .

Introduction To Computer

Computer 11 Notes — Sun, 08 Apr 2012 05:41:42 +0000

- Characteristics/Features of Computer

Speed
Accuracy
Reliability
Storage Capacity
Word Length
Diligence
Versatile
Automatic
Electronic
Non-intelligent

- Application Areas of Computer

Education
Communication
Business
Transportation
Banking
Helth
Security
Industry
Scientific Research
Entertainment
Weather Forecasting
Desktop Publishing
Designing
Satellite Controlling

- Aviation

Capabilities & Limitations of Computer
Advantages & disadvantages of Computer
History of Computer

- Mechanical Age

Abacus
Stepped Reckoner (Leibniz Calculator)
Napier Bone
Difference Engine
Slide Rule
Analytical Engine
Pascaline
Tabulating Machine

- Electro Mechanical Age

MARK-I [Also known as ASCC (Automated Sequence Controlled Calculator)
MARK-II
ABC (Atanasoft Berry Computer)

- Electric Age

ENIAC
EDAC
EDVAC
UNIVAC

Some Important Persons
o Joseph Jaquard
o Charles Babbage
o George Boole
o Herman Hollerith
o Lady Augusta Ada Lovelace

Input Devices

Computer 11 Notes — Sun, 08 Apr 2012 05:41:42 +0000

Some of the input devices used in a computer are keyboard, mouse scanner, joystick, touch screen, touchpad, track ball, bar code reader, light pen, optical code reader (OCR), MICR, OMR, microphone, digital camera, webcam, card readers, digitizing tablets, etc.

Keyboard

Keyboard is the most basic input device. It is used for text input. It contains multiple keys. User can provide input by pressing the key. The different types of key found in keyboard are:

Alphanumeric keys (A-Z, 0-9)
Function keys (Ctrl, Alt, Caps lock, Enter, Tab, Shift)
Special function keys (F1, F2, F3,……..,F12)
Cursor movement keys (?, ?)
Punctuation keys (,, “” , ’’, ?, !)
Numeric pad
Multimedia keys

On the basis of keys, keyboard can be classified as

XT keyboard -83 keys
AT keyboard -101 keys
Enhanced keyboard -103 and more keys

A keyboard contains an electronic circuit known as keyboard encoder. This circuit detects the pressed key, generates its electronic signal and transmits towards CPU.
On the basis of connectivity, keyboard can be wire or wireless.

Mouse

Mouse is a most common pointing and selecting device. It is used in graphical user interface. Mouse contains buttons for providing inputs. User can provide inputs by moving the mouse and pressing the button. On the basis of buttons, mouse can be:

Two-buttoned mousse
Three-buttoned mouse

Usually, the left button of the mouse is for normal selection and the right button is used for special function and central button is used for scrolling a document.
On the basis of working mechanism and its architecture, mouse can be classified as:

Mechanical mouse
Opto-mechanical mouse
Optical mouse

Mechanical mouse contains a rubber ball and a pair of rotating wheels. When the mouse is moved on the table, the ball rotated which results in rotation of the wheels and generates electronic signal.
Optical mouse operates using reflection of light. It is easier to use but usually less reliable than mechanical mouse.
The opto-mechanical mouse contains both mechanical and electric component.

Track ball
Trackball is the modification of mechanical mouse. It contains rubber ball on its top. User can move the cursor by rotating the ball with finger. It also contains two buttons on the either sides similar to mouse. It was used in older laptops.

Track pad/Touch pad

Track pad is the modification of optical mouse, and touch pad is further modification making it touch sensitive. It contains a window with two buttons on the either sides. User can also provide left click option by tapping the window with the finger. It is mainly used in portable devices like laptops, notebook, palmtop, etc.

Joystick

Joystick is a hand held pointing device which is mainly used for playing games. It is used for controlling objects, their movement, direction and speed of movement. Modern joysticks handle can move in any direction. When the handle is moved, the electronic circuit in the base detects the movement and sends corresponding binary signals to CPU.

Light pen

Light pen is used for creating drawings, designs by directly touching the screen. It is mainly used by designers, architects, engineers, etc. it is used in monitor not having touch screen facility. It is a pen shaped structure containing photo sensitive tip which can capture light emitted from the monitor and mark the position on the monitor.

Touch screen

Touch screen is none of the common input device at present mainly for portable computers. User can provide inputs by directly touching the screen with the metallic pen (stylus), finger or any pointed object. Touch screen is developed by using either of the following technologies:
a) Pressure sensitive
b) Capacitive
c) Infrared

Scanner

Scanner digitizes hard copy or printed images which can be used in digital computers. Scanner copies the image and draws a new digital image in its memory similar to hard copy image.

OCR (Optical Character Reader)

OCR digitizes handwritten or printed text.
Printed text will have fewer errors than hand written. It directly converts hand written text into digital text which can be edited. OCR contains predefined format of all the characters. During digitizing process, it creates an image of the character and compares it with stored format to determine the character.

MICR

It stands for Magnetic Ink Character Reader. MICR is an OCR that can digitize text written or printed by using magnetic ink like iron oxide or barium ferrite. It is used in security systems and for processing cheque in bank.

OMR

It stands for Optical Mark Reader. It is used for answer sheet correction in multiple choice questions. With the use of OMR answer sheet correction will be faster and error free.

BCR

It stands for Bar Code Reader. Bar codes are the magnetic lines used for storing the information about the product like manufacturing date, expiry date, company name, etc. BCR is used to read the information stored in bar codes. Bar codes are also used in security system.

Microphone

It is an input device for sound. It captures sound wave, converts it into digital format and provides it to the CPU. Common mobile computing devices like PDA, smart phone contains microphone.

Digital camera, Web camera

Digital camera captures real time images and video and stores it in a digital format. The image captured by digital camera can be directly used in a digital camera.

Web camera is a digital camera used in internet. It usually captures low quality images so that it could be transmitted at a faster speed.

Card reader

It is used to read the information stored in cards like ATM card, Credit card, Smart card, etc.

Digitizing tablet

It is used to digitize large map or hardcopy images. It is also used to track the movements of living beings and capture them in digital format.

Introduction To Windows 3.1

Computer 11 Notes — Sun, 08 Apr 2012 05:41:42 +0000

Introduction to windows 3.1

If somebody buys a new computer today, it will probably come loaded with Windows. It is a Graphical User Interface (GUI) program meant for IBM compatible PCs. It provides the flexibility of using graphical icons and work interactively with the computer. One doesn’t need to remember operating system commands and type them. He just has to move the small mouse arrow key, known as mouse pointer around the screen (better known as window) and select the require command by pressing the click button. Each window, which represents programs, can be resized and moved around the screen. Multiple windows can appear on the screen at the same time giving user the flexibility of operating more than one program.

Objectives

At the end of this lesson you would be able to:

Understand the concept of windows working environment
Differentiate between confessional character display Interface and graphical user interface.
Explain about various features of Windows
Understand various Icons and their functions.

Types of windows and icons

Before using Windows effectively, it is very essential to understand the concept of window type and Icons used in Windows. The entire screen is termed as Windows Desktop, on which all windows are displayed. It is same as that of laying all your work on the surface of your working table. Here the working table is the Windows Desktop and all your work is individual windows on the desktop.
In general, there are two types of windows and three types of Icons which window uses. The window types are:

Application windows, which displays the executable windows program in GUI mode. These windows can be, opened, closed, resized and moved around the screen or the desktop.
The other type of windows is a document window, which are generated by the executable or application program. These document windows cannot be sized or moved outside the limit of its parent application windows.

Windows uses three types of icons, namely application, document and program icons.

Application icons are the minimized version of the currently running application program. This icon appears at the bottom of the desktop and can be maximized.
Document icons are the reduced document windows. When maximized, it appears within an application window’s workspace.
Program icons that appear within Program Manager and clicking on these icons activate the associated applications and also load the related documents or files.

Parts of windows

All most all windows have common components. The components are:

Title Bar
Buttons for Minimize, Maximize and Restore
Borders for Resizing
Menu bar and Pull-down menus
The scroll bar

1. Title bar
Title bar is displayed in color at the top of the windows. It contains the name, or the title of the current windows. The windows can be moved around the window desktop using this title bar.

2. Buttons for Minimize, Maximize and Restore
These buttons are displayed at the top-right corner of the screen. As the name suggests, minimize button is used to reduce the current windows into an applications icon, which will appear at the bottom of the windows desktop.
Similarly, maximise button is used to expand the current windows to take up the entire desktop.
Restore button is used to restore the state of the windows, where it was before maximization.

3. Borders for resizing
A thin border appears around the windows, which can be used to resize the current windows. To resize the current windows, just place the pointer on the border (this will become two-headed arrow «) of the windows, click the mouse button, hold and drag to the desired location. The windows will change its size. Vertical and Horizontal borders can be used to change the width and height of the windows respectively, while corner border can be used to change width and height simultaneously.

4. Menu bar and pull-down menus
Menu bar is located under the Title bar and contains the related Pull-down menus for the currently active windows. Clicking on a menu name will activate a pull-down menu with various options to select.

5. The scroll bar
When the active windows cannot accommodate the data to be displayed then it provides a scroll bar that helps to move through the data. Vertical scroll bar allows to view data by moving up or down through a document, whereas horizontal bar allows the movement from left to right. The vertical scroll bar appears on the right side of the active windows and horizontal scroll bar at the bottom.

Windows dialogue boxes
While using application program in window, sometimes it is require to change the settings within a program for example default margin the a word processing document, default printer, font type and size etc. All these are accomplish by window’s dialog box, which appear when the menu with an ellipsis (..) beside it is activated. It is basically serve two purposes one that it allows to change/rest the parameters related to currently running application and displays information such as warnings, error message etc. The displayed dialog box may contain the followings:

1. Command button
This button activates an action. The most commonly used command buttons are OK and CANCEL. Command buttons with an ellipse (..) indicate a link to another dialog box.

2. Check box
Check box allows selecting one or more option from a list of options. When selected an X appears besides the option selected and the corresponding option becomes active.

3. List Box
List box displays a series of options available in a column. To select an item, move the mouse pointer to the item and click on it. If the number of items is more than the height of the list box, then it provides a scroll bar to move through the entire range of items in the list box.

4. Option Buttons
It has the same features as that of check box. It allows selecting an option in a list of choices. When selected, the small hollow circle gets filled. Once an option gets selected from the available set of options, other options automatically get deselected.

Disk space required

Microsoft Windows along with MS-DOS version 6.0 requires a minimum of 15.8 MB and maximum of 18.3 MB of free disk space. Minimum disk space assumes no optional components, network or printer settings. However maximum disk space includes all installable components, network and printer.

Windows vs. Microsoft-DOS

Windows provides tools to accomplish all the tasks in case of file and directory management as in MS-DOS. The main difference is how the work is done. Rather than remembering all the commands and typing them at the DOS prompt, in Windows one can move the mouse pointer to the required command, and windows will execute the command. Windows supports all the File and Directory management commands of MS-DOS and it also supports Microsoft-DOS conventions in working with files such as wild card characters.

Windows programs

In this section, programs provided in windows such as program Manager, File manager etc. are discussed. These are vital part of windows operating environment and one must know how to work and use these programs.

1. Program Manager
When window program starts Program manager is the first windows displayed on the window desktop. The only way to leave windows is to closing or exiting this program manager. Within Program Manager there is some secondary window known as group windows, which appears as fully opened window such one with title ‘Main’ or as group icons, which appears at the bottom of ‘Main’ windows. A group icon is a group window, which can be minimized. Group windows contains logically related programs, such as one group windows can contain all programs associated with database while another may be for word processing.
There are five default groups in Windows. They are;
Main group of windows contain all the system applications: File manager, Print Manager, MS-DOS prompt, Windows Setup and PIF Editor.

Applications group consists of all the application found on your hard disk, while installing the windows. How ever if, during installation process if you chose the Custom Setup option and chose not to have Windows set up applications from your hard disk, the program manager will not contain an Application group.
Accessories group is made of windows based applications for word processing (Write), drawing (Paint), communications (Terminal), plus several other useful applications.
Games group contains windows based games.
Start Up group has application that loaded when windows system starts initially. Any applications can be added to this group. This group remains empty until, an application is added to it.

Windows provide the flexibility to install other group windows also.
Group windows can be resized, moved and it contains the icons for the program, which can be executed. Program items can be added deleted in-group windows and they can be copied between group windows also.
However neither the group windows can be moved outside the program manager nor the group icons. By selecting the icons, one can run the associated program files. All the program items can be moved between groups copied or renamed.

2. File manager
As the name suggests, File manager is used to manage or manipulate both disk and the disk files. It provides visual representations of all disks and disk files in the system.
As displayed in the above figure, the directory structure for the hard disk of the system and all the files in the current directory, appear in a document windows, known as directory window. The attributes of one or more file can be changed, by selecting them from the directory window. They can also be moved between directories, or opened, renamed, printed, deleted or copied.

1. Selecting File(s) and directories

File Manager allows you to select one or more than one files at a time for copying, moving or deleting or to perform other related task.
To select a file or directory clicks the desired icon. Or press the TAB button to move to the list of files, and then use the direction keys or arrow keys to select.
To select consecutive files, select the first file, press and hold down the SHIFT key, and then click the last file on the desired file list or group. Alternatively, select the first file, press and hold down the shift key and then use arrow keys to extend the selection to the last item in the group.
To select or cancel selection of the non-consecutive files, press and hold ctrl key and click on each file. Alternatively, press SHIFT and F8 key, use arrow keys to move to each file, use spacebar to select the file or to cancel already the selected file, then press shift and f8 again.
To select similar type of file, activate the Select Files option from the File menu bar. In the text box of the dialog box specify the type of files to be selected. For example *.doc to select all files in the current directory that has .doc as extension or secondary name.

In-text questions 1

1. State True or False.

File Manager is used to start Windows.
Group windows and group icon can be moved out of Program Manager
File maintenance is done using File manager in windows.
To activate a program when windows starts, you need to add it to File manager.
Print manager and File Manager are available in Games windows.

What you have learnt
In this lesson you were introduced to the concept of windows working environment and graphical user interface. It also discussed various features and components of windows. It explained with examples the icons and their functions. This also discussed how to select files and directories.

Terminal questions

Briefly discuss why Windows is popular.
Briefly explain about different components of windows and how to start windows.
How a group icon is different from individual program Which group programs are loaded when windows starts-up?
Can a DOS based application be used in Windows?

Feedback to in-text questions

False
False
True
False
False

Generation Of Computer

Computer 11 Notes — Sun, 08 Apr 2012 05:41:42 +0000

Generation of computer

The computers of electronic age are further divided into 5 generation on the basis of technology used by the computer. The different generations are:

First generation of computers
Second generation of computers
Third generation of computers
Fourth generation of computers
Fifth generation of computers

1. First generation of computers

Technology used: Vacuum tube
Operating speed: Millisecond range
Programming language used: Machine language
Memory used Primary memory: Magnetic core memory Secondary memory: Magnetic drum, Magnetic tape.
I/O device:
Punched card as input device, printing device as output device.
Use: Simple mathematical calculation.
Computers were extremely large in size, and they required special cooling system. e.g.: ENIVAC, EDVAC, UNIVAC, etc.

2. Second generation of computers:

Technology used: Transistor
Operation speed: Micro second range (10-6 sec)
Programming language used: Assembly language
Memory used Primary memory: Magnetic core memory. Secondary memory: Magnetic drum, Magnetic tape.
I/O: Punched card as input device, Printer as output device
Use: Computers were used for complex scientific calculations.
The size, cost, power requirement, heat generation decreased compared to previous generation.
Processing speed, storage capacity, use of the computer increased compared to previous generation.
E.g.: IBM 1620, IBM 7094, LEO MARK III, etc.

Advantages of transistor over vacuum tube:

One transistor could replace one thousand vacuum tubes.
Size of a transistor is 1/200 th times of a vacuum tube.
The power requirement of a transistor is 1/20 th times of a vacuum tube.
Transistors are more reliable than vacuum tube.

3. Third generation of computers

Technology used: IC (Integrated Circuit)
Operating speed: Nanosecond range (10 -9 sec)
Programming language used: HLL (High Level Language) Like FORTAN, COBOL, PASCAL, C, C++, etc.
Memory used: Primary memory: Semiconductor memory (silicon) Secondary memory: Magnetic tape, Magnetic disk like floppy disk, hard disk, etc)
I/O device: Keyboard as input device, monitor as output device.
Use: Computers were used for managing population census, bank, insurance company, etc.
Concept of database was developed and used.
Size, cost, power requirement, heat generation decreased compared to previous generations.
Processing speed, storage capacity, use of the computer increased compared to previous generations.
E.g.: IBM 360 series, ICL 900 series, Honeywell 200 series, etc.

IC and its types:
IC is a small silicon chip which contains large number of electronic components like transistor, resistor, capacitor, etc.
The process of creation of IC is called fabrication.
Types of IC on the basis of number of electronic components.

SSI (Small Scale Integration)(1-20 components)
MSI (Medium Scale Integration)(21-100 components)
LSI (Large Scale Integration)(101-1000 components)
VLSI (Very Large Scale Integration)(1001-10000 components)
ULSI ( Ultra Large Scale Integration)(More than 10000 components)

4. Fourth generation of computers:

Technology used:- VLSI (or Microprocessor)
Operating speed:- Pico second range
Programming language used: 4GL (Problem Oriented Language)
Memory used: Primary: Semi-conductor memory Secondary: Magnetic tape, Magnetic Disk, Optical memory (CD/DVD/ Blu ray), Flash memory(pen drive, memory card)
I/O device: Advanced I/O devices like mouse, touch screen, scanner, LCD, LED, color printer, etc are developed.
Use: Computers are used for different task in different areas like education, business, hospital, transportation, military, etc.
Microcomputers like desktop PC, laptop, notebook, etc, are developed.
The popular communication media like internet, email, mobile communication, etc were developed.
Advanced, user friendly, web based software, etc are developed.
Size, cost, power requirement, heat generation decreased compared to previous generation.
Operating speed, storage capacity, use of the computer increased compared to previous generation.
E.g.: IBM desktop PC, HP laptop, Acer notebook, Mac book, etc.

5. Fifth generation of computers:

Technology to be used:- Bio-chip
Operating speed:- Femto second range
(10 -15 second) / TIPS
Programming language to be used:- Natural language
The computers will have AI.
The computers will be used in complex calculation where intelligence of the computer is required.
The computers will have parallel processing in full fledge.
The computers will be based on KIPS (Knowledge based Information Processing System)