Basic Concepts of Operating System
The word operating system is self-indicating that this is a system for operating a devise. An operating system is a program which acts as an interface between a computer hardware and users of the computer. It provides such an operating system, the primary goal is to make computer system convenient to use and the secondary goal is to use the computer hardware in an effective manner. The OS helps in a file management, program execution, system management and memory management. Some popular operating system are: LINUX, Window, OSX, VMS, AIX OS/400, Z/OS etc.
Main Layers in an Operating System
Layers in an Operating System is defined as the software which provides interface between different components of the computer. The following five layer model is often used in an Operating System.
Kernel: It connects the application software to the hardware of a computer. Hence, it manages memory access for programs in the RAM. It also allocates processor time and memory to each program and determines when each program will run.
Memory Management: It is responsible for starting the physical memory of the computer between processes and handling programs which require more memory than physically available.
Input/Output: This layer controls all physical communication with external devices like disk drive, keyboard, printer and display. If a higher layer require access to a device, a request is sent to the I/O layer.
File Management System: It is also known as file system. It is responsible for organising and managing the storage of data on permanent media such as hard and floppy disk drives and tape streamers.
User Interface: It is defined as the space where interaction between human and machine occurs. There are two types of user interface: the text-based Command Line Interface (CLI), used in MS-Dos and LINUX, and the icon-based Graphical User Interface (GUI), used in windows and Apple Mac OS.
Classification of Operating System is as follows:
vMultiprocessing: Supports in running a program on multiple CPUs within a single computer system.
vMultitasking: Allows you to run more than one program at the same time.
vMulti - user: Allows multiple user to run the program at same fraction of time.
vMultithreading: Permits all different modules of a single program to run at the same time.
vReal - Time: responds to input immediately.
Microsoft windows is a type of Operating System available in 32 and 64 bit versions. It was developed by Microsoft. It provides a Graphical User Interface (GUI), virtual memory management capabilities, multitasking functionalities and support for many peripheral devices.
Earlier in Microsoft Windows Operating System, there was more...
Flowchart and Computer Languages
Computer programming language is defined as the type of language used for writing the source code of computer program, whereas, computer programs are set of instructions that enable a computer to interact with the user, peripherals and information. These instructions are written in a language called computer programming language. The process of writing computer programs is called computer programming. Before writing a computer program, first you have to develop an algorithm. An algorithm is a group of logical instruction that generates the output according to given input. These algorithms are written in Pseudocode. Pseudocode is an informal description of a computer program that is written in simple English.
While writing a program using a computer programming language, such as C, you need to follow the syntax of that language. A programming language also provide operators that enable you to perform various tasks, such as computing and manipulating values of variables, comparing values of different variables of same data types and testing multiple conditions. After developing algorithm, you need to develop flowchart.
How to Develop Flowchart
Flowchart is a technique that allows you to represent computer program graphically. Each step in the flowchart is represented by a different symbol and contains a short description of the step. Using flowchart, you can easily understand the logic of a program. A flowchart represents the logical and operational steps to be performed within the system for transforming the input process into output. Flowchart serves as a basis for discussion and communication between the system analysts and the programmers.
To create a flowchart, you need to use the following symbols:
This symbol is used to represent the start and end of an algorithm or process. It is also called terminator box.
This symbol is used to represent the logic used in a process or algorithm. It is also called processing box.
Networking and Internet
A computer network is a group of computers that are interconnected to share information and resources. The first networks were implemented by both IBM's SNA Systems Network Architecture) and Digital's network architecture. Internet is the biggest example of computer networking. Through Internet you can send email or file to any location in the world. While developing computer network, you need to use communication devices, such as modem and router. Basically, communication devices are usefull to send and receive data on the network.
Network means connecting with each other. Computers form network for sharing information and resources.
A number of computers and peripheral devices are interconnected in such a way that they can share resources and information. This is known as network. Networking is mainly concerned with the communication between computer systems. A computer network is any set of computers connected to each other with the ability to exchange information. Computer networking can be considered as a sub discipline of computer science, information technology and computer engineering.
Different Types of Networks
Computer network is divided into three main categories:
LAN is commonly known as Local Area Network. It is used to connect the computers - --d other network devices so that the devices can communicate with each other to share the resources. The resources to be shared can be a hardware like printer or a software like an application program or data. The size of LAN is usually small. The various devices in LAN are connected to central devices called Hub or switch using a cable. This network is limited to a relatively small area, such as a classroom, a school or a single building. This type of network has the lowest cost.
Advantages of LAN
vAbility to share hardware and software resources.
vAll network users can save their data on hard disk of the server computer.
vComponents and system evolution is possible.
vSupport for heterogeneous forms of hardware and software.
vAccess to other LAN's and WAN's.
vSecure transfers at high speeds with low error rates.
Disadvantages of LAN
vEquipment and support can be costly.
vSome types of hardware may not interoperate.
vA good LAN is required to be on all the times.
vA lot of times a network shares one internet connection only. If many computers are running at once, it can reduce more...
Working With Microsoft Word 2013
The Microsoft Word brings new revolution in documentation. Windows platform of Word was released in 1989. Since 1989, many versions of Word has been launched by Microsoft, such as Word 95, Word 97, Word 2000, Word 2002, Word 2003, Word 2007, Word 2010, Word 2013 and word 2016.
Microsoft Word is a popular word processing software that allows the user to create more accurate, concise and correct documents. It's also useful to create brochures, memos, merging letters and newsletters. Microsoft Word enables you to create documents using text formatting, graphic, chart and page formatting tools. Using Microsoft Word, you can add text, tables and graphics more easily.
Word enables various features that allow creating different kinds of documents.
Important Elements in Word 2013
Displays the name of the active document and it is present at the top of the window.
Word contains two types of ruler including horizontal and vertical. Ruler provide measurement of ongoing page as well as quick access to margins, tabs and indents. It is present below the toolbar and on the left side of the application window.
Allows viewing different areas of the active document. It is positioned along the right side and bottom of the text area.
Displays various types of information about the active document, such as the current page number. It is positioned across the bottom of the application window.
Working With Microsoft Excel 2013
Microsoft Excel 2013 is a spreadsheet program that is used to manage, analyse and present data. Spreadsheet is an application software used for calculation based applications. In this application software, a user can edit and modify data and also calculates average, sum, difference, etc. A Spreadsheet contains rows and columns which forms many cells. There are 1, 048, 576 rows and 16, 384 columns in MS-Excel 2013. The Microsoft Excel opens with name, book 1, by default book 1 contain one sheet that can be renamed and additional worksheet can also be added in a work book 1. In the previous class, you have already read about some basic features of MS-Excel. In this chapter, we ?will study about the working with Microsoft Excel application software.
Entering Data in a Cell
Every cell in a worksheet has its own address. The data in a cell is entered by selecting a cell and pressing F2 key or double clicking the selected cell. Press enter or tab key to move to the next cell. Press Alt + Enter key on the keyboard to apply a line break. For over writing data in a cell, press Enter key after writing new data in a cell.
Moving the Content in a Worksheet
Moving the content from a selected range of cells into another location, move the contents to the new location. The cells must be selected using mouse or keyboard. You can use cut, copy and paste command to move or copy cells or their contents. To cut the selected range, right click the mouse and click on cut option from the drop down menu. Move the cursor at the corner of the first cell in which the item is to be moved. Now, click paste in the mouse right click drop down menu. Entire contents from the old location is moved into the new range of cells without leaving the old information. Whenever you copy or move a cell in Excel, it copies or moves the cell including formulas and their requesting values, cell formats and comments.
You can delete the entire content of a cell if the data is no longer needed. Deleting data does not remove any formatting applied to the new data.
To delete data:
vSelect the cell that contain the data you want to delete, and then press the delete key.
Filling a Range
The smallest area in which data is entered is the cell of a worksheet. Series of numbers can be inserted in a range of cells by clicking, (Editing Fill Series command) or dragging the fill handle.
Fill Handle in a cell is appeared after clicking in the cell. The lower right corner of a cell has more...
Working With Microsoft PowerPoint 2013
Microsoft PowerPoint is an application software which is used to display the presentation. In Microsoft PowerPoint presentation, an audio, a video and pictures can be displayed on the screen. The PowerPoint presentations are generally used in business meetings and for training and educational purposes. We have already studied about some basic features the Microsoft PowerPoint in previous classes. In this chapter, we will study about some advanced feature of PowerPoint.
Creating New Presentations
The presentation is a collection of individual slides that contains information on a topic.
To Create a presentation, follow the steps listed below:
vClick on File menu.
vSelect New option.
vThe new presentation dialog box will appear.
vClick on blank presentation option or any of the template design. Shortcut key to create a new blank presentation is Ctrl + N.
A slide is an individual page of a presentation. Slides keeps attention of audience during a presentation and provide additional supporting information in textual or graphic format. Slides contain placeholders or areas on a slide that are enclosed by dotted borders. Placeholders can contain many different items, including text, pictures, and charts. Some placeholders have placeholder text, or text that you can replace, and thumbnail-sized icons that represent specific commands such as Insert Picture, Insert Chart, and Insert Clip Art. Hover over each icon to see the type of information you can insert.
To insert text into a placeholder:
vClick inside the placeholder. The placeholder text will disappear, and the insertion point will appear.
vType your text once the insertion point is visible.
vClick outside the placeholder when you have entered all of your text into the placeholder.
When you enter text or use the icons to insert items, the placeholder text and/or icons disappear as soon as you start typing.
About Slide Layouts
The placeholders are arranged in different layouts that you can select when you insert a new slide or that can be applied to existing slides.
A slide layout arranges your slide content. Layouts contain different types of placeholders you can use, depending on what information you want to include in your presentation. Each layout has a descriptive name, but the image of the layout shows you how the placeholders are arranged on the slide. You can use layout by clicking Layout button in the Slides group.
Creating Graphics in a Slide
PowerPoint allows the user to edit text and more...
Working With HTML
HTML stands for Hyper Text Markup Language and it is the most widely used language to design webpages. A web page is a digital page which comprises of multimedia. A group of webpages forms a website. HTML was developed with the intent of defining the structure of documents like heading, paragraphs, lists etc. HTML defines the structure and layout of a web document by using a variety of tags and attributes. When you save an HTML file, you can use either the .htm or the .html extension.
An HTML tag is a set of characters constituting a formatted command for a web page. A web page consists of various types of tags to denote the various elements in an HTML document, HTML tags consists of a left angular bracket (<), a tag name and a right angular bracket (>). Tags are usually paired (e.g., <Tag>. and </Tag>) to start and end the tag instruction. The end tag looks like the start tag except a slash (/) precedes the text within the brackets.
Some elements may include an attribute which is additional information included inside the start tag. An attribute defines the characteristics of an HTML element. For example, you can specify the alignment of text (right, left or center) by including the appropriate attribute with the image source HTML code.
Headings are used to arrange the contents in a systematic way. HTML has six levels of headings, number 1 to 6, with 1 being the largest. Headings are typically displayed in larger and / or bolder fonts than normal body text. The first heading in each document should be tagged <H>.
<Hn> Heading/sub-Heading </Hn>
Where n is a number between 1 and 6 specifying the level of the headings?
Some Tags in HTML
Every HTML document contains certain standard HTML tags. They are as follows:
The HTML element tells your browser that the file contains HTML coded information. The file extension .html also indicates this on HTML document and must be used. It comes in a pair <HTML> and <HTML>
The Head element identifies the first part of your HTML coded document that contains the title. It contains title tag. It also comes with opening and closing tags <HEAD> and </HEAD>
The Title tag contains your document title and identifies its content in a global context. The title is typically displayed in the title bar at the top of the browser window, but not inside the window. The title is also what is more...
A series is a uniform set of one or more digits, letters, figures, etc. in which terms follow a certain rule. To complete a series or identify a term, student is required to identify the rule on which the given series has been formed. Let us illustrate readers with the help of examples and their explained answers.
1. Choose the missing term to complete the given series. 3, 5, 10, 12, 24, 26, 52,?
We observe that 2nd term 3rd term 4th term 5th term
Clearly the pattern is:
So, 8th (required) term
Hence the correct option is (c).
2. Five consecutive figures P, Q, R, S and T given below form a series by using a definite rule. Select a figure from the options to continue the series.
In P and Q, the two elements interchange positions and the smaller element gets enlarged while the larger element gets reduced in size.
In the next step, the smaller element is replaced by a new small element and the larger element is replaced by a new large element.
These two steps occur alternately. Inserting the missing character A pattern is a set of number or a set of figures in which a number/letter is missing.
To identify the missing number/letter a student is required to decipher the pattern.
The following example would be helpful for pattern based problems.
3. Which number will replace the question mark (?) ?
From figure (i):
From figure (ii):
From figure (iii):
Hence the number 26 will replace the question mark.
Logical Venn Diagrams
Venn diagram is a pictorial representation of classes representing items and their common properties. We usually use circles to draw a Venn diagram. A Venn diagram consists of two or more circles. Circles may or may not have some common regions according as the respective classes do or do not have common properties amongst them. Note that the given statements are taken to be true disregarding commonly known facts. Let us illustrate the concept of Venn diagrams with the following examples.
1. Which of the following figures represents the relation between 'Parrots', 'Birds' and 'Crows' ?
(a) (b) (c) (d)
Parrots and crows are different from one another.
So, the Venn diagram of these two would be as follows:
Further, both parrots and crows are birds. So, the final Venn diagram is:
So, the correct option is (b).
2. Direction (I-II): Study the diagram given below and answer the following questions based on it.
I. What does letter D represent?
(a) Uneducated women in villages
(b) Unemployed women in villages who are not educated
(c) Educated unemployed women
(d) Educated employed women
Letter D lies inside the triangle and square only.
So, D represents unemployed women in villages.
Also, D lies outside the circle.
So, D represents uneducated women.
Hence, D represents unemployed women in villages who are not educated. So, the correct option is (b).
II. Educated unemployed women in cities are represented by _______.
(a) E and F (b) D (c) F (d) G and E
Only the letter F represents educated unemployed women in cities.
So, the correct option is (c).
In such type of problems, a particular relationship is followed between two pairs of letters, words, numbers, group of numbers, group of letters given on the either side of (::). Student has to identify the relationship and choose the correct answer from the given four options followed by the question.
1. Which number completes the second pair in the same way as the first pair?
120 : 12 :: ? : 4
In the first pair, 1st number number.
Similarly, in the 2nd pair, 1st number
Thus, the required number = 40
So the correct option is (a).
2. Which figure will complete the second pair in the same way as the first pair?
Each one of the upper elements is replaced by an element similar to the lower element(s) and each one of the lower elements is replaced by an element similar to the upper element(s).
So, the correct option is (b).
We classify various items into a group on the basis of their common properties.
These items may be numbers, letters, figures, things, places etc.
In such type of problems, some items are given.
All these items except one are similar in some manner.
A student is required to identify the odd one out.
Let us illustrate problems with the help of examples.
3. Find the odd one out.
Except 42, all other are odd natural numbers.
So, the correct option is (b).
4. Choose the figure which is different from the rest.
Except , all other are formed from two straight lines.
So, the correct option is (d).