Classification of Computer Based on Size and Capability
Classification of computers are based on their architecture, speed of executing commands or instructions, peripheral used and also their uses. Microcomputers are usually used in home and offices and only a single user can perform the task using a microcomputer. Its storage and data handling capacity are limited as per the requirement for home and office work. The another type of computer is called minicomputer which has usually larger storage and can handle multiuser at a time. This chapter includes the classification of computers.
Computers are classified on different parameters, such as, storage capacity, processing speed and component (CPU) used in computers. Depending upon the components used and features of different computers, they are classified into four groups, Microcomputers, Minicomputers, Mainframe computers and Supercomputers.
Micro Computer is a computer whose CPU (Central Processing Unit) is a microprocessor. All the components of a microprocessor are on a single integrated circuit chip. Micro computer can be categorized as the desktop, programmable and workstation. The microprocessor based computers are called third generation computers. They are the backbone of the modern computer era. The first and second generation computers are based on vacuum tubes and bipolar junction transistors.
Desktop computer is a type of microcomputer. A desktop computer has a keyboard for input data, a LCD or CRT monitor to display information and Central processing unit tower contains storage, memory, different types of drives, such as, CD drive, hard drive, etc. A desktop computer is mainly used at home and office applications.
Programmable Computers (PDA)
Personal digital assistance is a type of hand held programmable digital computer. It is used as notepads, address books and can connect to world web wave to share information. A PDA is equipped with mobile phone hence, called smallest computer.
A workstation computer has greater memory capability and more extensive mathematical abilities. It is connected with other workstation computers or personal computer to exchange data and mostly used for scientific applications. It also supports multitasking applications.
Minicomputers were introduced in early 1960s. They were faster than micro computers. Basically these computers were mainly multi-user systems, where many users work on the systems. Generally these types of computers had larger memories and greater storage capacity. They had large instruction set and address field. These kinds of computers have efficient storage for handling of text, in comparison to lower bit machines. Due to more efficient processor, speed and memory size, minicomputer was used in variety of applications and could support business applications along with the scientific applications. Minicomputer was a multi-user system which means more than one user could use this system simultaneously.
Comparison of Micro and Mini computers
An Operating System is a master control program. Basically it is system software that manages the operation of a computer. Without an operating system computer cannot work. The computer is useless unless it is provided with essential software that makes it ready to use. As we have seen that an operating system is software, which makes the computer ready to use by a process called booting. Basically booting is a process which loads operating system from disk to RAM.
About twenty years ago Steve Jobs and Wozniak, the founders of Apple, came up with the very strange idea of selling information processing machines for use at the home. The business took off, and its founders made a lot of money and received the credit they deserved for being daring visionaries. But around the same time, Bill Gates and Paul Alien came up with an idea even stranger and more fantastically: selling computer operating systems. This was much wider than the idea of Jobs and Wozniak. A computer at least had some sort of physical reality to it. It came in a box, you could open it up and plug it in and watch lights blink. An operating system had no tangible incarnation at all. It arrived on a disk, of course, but the disk was, in effect, nothing more than the box that the OS came in. The product itself was a very long string of ones and zeroes .that, when properly installed and coddled, gave you the ability to manipulate other very long strings of ones and zeroes. Yet, now the company that Gates and Alien founded is selling operating systems like Hindustan Lever Limited sells detergents. New releases of operating systems were launched as if they were Bollywood blockbusters, with celebrity endorsements, talk show appearances and world tours. The market for them is vast enough that people worry about whether it has been monopolized by one company. Even the least technically minded people in our society now have at least a hazy idea of what operating systems do; what is more, they have strong opinions about their relative merits. To be more elaborative on the topic, every general-purpose computer requires some type of operating system that tells the computer how to operate and how to utilize other software and hardware that are installed on to the computer. All software programs developed today require some type of Operating System to operate properly. MSDOS, Unix and Windows are all examples of operating systems. Because the history of computer operating systems parallels that of computer hardware, it can be generally divided into five distinct time periods, called generations, that are characterized by hardware component technology, software development and mode of delivery of computer services.
Structure of OS
The internal structure of operating system is divided into layers. The outermost layer is called user interface and innermost layer is hardware.
The following are the main layers more...
Introduction to Logic Gates and Number System
A logic gate is an idealized or physical device implementing a Boolean function, that take inputs and produces a single logic output.
Computer are made up of logic gates. Logic gates take information coming in and output different information depending on what type of gate they are.
In 1938, Claude E. Shannon introduced a two ? valued Boolean algebra called Switching Algebra, which applied the concept of Boolean Algebra to the design of electrical circuits.
Truth Table and Logic Gates
A truth table is a representation of all possible combinations of Input values and their result in a tabular format. If the result of a logical expression of logical statement is always true or 1, it is known as Tautology. If the result expression or logical statement is always false or 0, it is known as Fallacy.
Briefing on Internet and Networking
In the world of Information Technology, some set of rules are defined and these are known as protocols. Basically the set of protocols enables two systems to communicate and transfer data on the network. Any electronic device which is having a capability of sending and receiving data is a system. Protocols are generally implemented by software, hardware or a combination of the two.
The information which identifies the protocols are the following:
vTo identify the corrupt messages, error checking is to be used.
vWhile receiving messages, it generally indicates the receiving devices.
vWhile sending messages, it indicates the sending devices.
vTo compress the data transmitted through the network, the method data compression is used.
The following table lists some important networking protocols:
NetBIOS Enhanced User Interface (NetBEUI) is the fastest protocol and does not require any configuration to implement. NetBEUI is simple to use.
AppleTalk is a routable protocol and is mainly used to communicate with Macintosh computers on the network.
Transmission Control Protocol/Internet Protocol (TCP/IP) is also a routable protocol. TCP/IP is supported by most of the OS. It is more reliable than other protocols.
NWLink is used in Novell NetWare networks. This protocol is easy to install and also a routable protocol. The NWLink protocol is faster than TCP/IP but slower than the NetBEUI.
The Internet goes back to early 1960's. J.C.R. Licklider of MIT (Massachusetts Institute of Technology), first proposed a global network of computers in 1962 and moved forward to the DARPA (defense Advanced Research Projects Agency) in late 1962 to head the work for its development.
In old days Internet was known as ARPANET (Advanced Research Projects Agency Network). It was started online in 1969 under a contract led by the renamed ARPA (Advanced Research Projects Agency), which initially connected four major computers at universities in the southwestern US UCLA (University of California, Los Angeles), Stanford Research Institute, UCSB (University of California, Santa Barbara) and the University of Utah). Internet is the best example of WAN (Wide Area Network). A WAN is one of the computer networks which was established on a large geographical area. While connecting the Internet with your computer you need modem. Basically modem is one of the most important parts for using Internet services. This works as a key because it receives the packet of data or signals through the service provider and thus after receiving it, it allows user to use the packet of data for surfing. Without modem surfing is unable to proceed.
The following are the advantages of the Internet:
Using Internet you can send any information, greeting and any type of file, such as picture to any location of the more...
Introduction to MS-Access 2013
Our lives revolve around to obtain, upgrade and maintain data and to a great extend depends upon it. From the normal daily life to working in an organization to the growth of any nation, everything depends upon on information.
However, data in its raw and unprocessed form is meaningless, but when such data is converted into information it is useful. Hence it is essential to provide a structure to the available data and organise it, which can be achieved with of a database. Database is an organised collection of information that can be easily be accessed, managed and updated.
Need of Database
Earlier, it was difficult to maintain a database which consists of hundreds and thousands of records. However, when a piece of information was to be updated, it had to be done separately in all related files. These problems created the need for designing a database which could handle vast amount of data. A database management system (DBMS) is a powerful tool used to store data, secure it, protect it and make it quickly available to people who need it. We need DBMS for the following reasons:
Data Storing: Large amount of data can only be managed with the help of efficient DBMS. For example most medium and large banks rely on databases to store customer information. Because this information is accessible wherever they need all over the world through internet, customers don't have to go to a local banking branch, for example, to access their account information.
Data Summarizing & Data Classification: Arranging the data and providing the facility to get the data on the basis of some criteria or category is again the main advantage of DBMS. Through this feature only we are able to get the summary of our bank statement based on some criteria whenever we need.
Data Retrieval: Efficient DBMS helps us to instantly retrieve the data from the database. Despite having millions of records of account holders in a bank database, it retrieves the data at lightning speed. Therefore, a DBMS not only stores large of data but also helps in quick retrieval of the same.
To reduce Data Redundancy and Inconsistency: DBMS helps in controlling data redundancy which in turn reduces data inconsistency. Data redundancy occurs when data is duplicated unnecessary which results in multi mismatching of copies of the same data.
Data Concurrency and Data Integrity: DBMS allows multiple transactions to access and modify the shared data at the same time, without violating data integrity.
Enforcement of Data standards: In DBMS, data is stored in a standard formats which helps to maintain integrity and exchange of data between the database system.
Ensure Data Security: Confidential data needs to be protected from unauthorized access. DBMS facilities to secure sensitive data by performing authorization checks and enforcing selective access to users.
Backup and Recovery Management: DBMS applies its theory for protecting a database against data loss and the process of more...
Introduction to CSS
Cascading. Style Sheets, fondly referred to as CSS, is a simple design language intended to simplify the process of making web pages presentable. CSS handles the look and feel part of a web page. Using CSS, you can control the color of the text, the style of fonts, the spacing between paragraphs, how columns are sized and laid out, what background images or colors are used, as well as a variety of other effects. CSS is easy to learn and understand but it provides powerful control over the presentation of an HTML document. Most commonly, CSS is combined with the markup languages HTML or XHTML.
Advantages of CSS
The main benefit of CSS is that style is applied consistently across a number of web pages. One command line can control several areas at one time, which is quite advantageous if there are changes that need to be made. You only need to alter one thing and the rest will follow. Because you don't have to change each page one at a time, web designers can be very efficient in creating and changing a website with only a few lines of code.
Improved Website Speed
Web designers only need to use a small amount of lines of programming for each page. And if there are less code, there are fewer lines to read, resulting in a faster load time for every page. With online users not willing to wait for a website to load, improving site speed will be most advantageous. Owners who bank on website performance to improve search engine rankings and customer base will benefit from CSS.
Easy to Maintain
Cascading style sheet not only simplifies website development, but also maintenance. All the codes are placed on one page, which means making improvements or changing a few lines will not involve going through several pages. And since a change with a single line of code is applied across the website, maintenance time and effort are significantly reduced.
CSS makes it easy to improve the appearance of a website by allowing you to create a much more stylish website since CSS offers a wide array of expressive style capableness. With CSS, you will actually obtain more control over your website's visual aspect. Now, designers can orchestrate the styles and design of several web pages in a flash.
One of the convenient features that CSS produces is the consistency it provides when you want to make changes to a website. When a change is made to your websites CSS Style sheet, you will have the ability to automatically correct or change every page throughout your website-all at once. You do not have to go in to each individual web page to make a particular change as CSS will instantly do it for you. If your website is rather large, this one simple feature will save you ample time more...
Working With HTML
In the contemporary world, Internet is the latest buzzword which is playing as vital role in the overall development of Information Technology. Internet is a network of millions of computers connected to each other through network cables and satellite links, sharing varied information and data around the world. The information on internet is available at different websites represented by www, which can be accessed by millions of users at anytime. Have you ever thought. Which technology is used to create a website? What lies behind the varied information that you get from Websites? Language is the key to all the question. We need a language to create a websites. HTML is the most widely used language to design web page contents for the Internet.
History of HTML
The founder of HTML was Tim Berners-Lee. It has become extremely popular and well-known in the 1990's when the Internet had been developing rapidly. HTML, initially known as GML(General Mark-up language).It was a powerful tools that aimed at creating documentation language in which one could mark the title, headings, text, font selection and much more. In 1986, this concept got standardized by ISO and was named SGML (Standard Generalized Mark - up language), which is a higher level markup language that has long been a favourite of the department of defence and many other organizations with a truly large volume of document to manage. Like HTML, it describes formatting and hypertext links an defines different components of a documents. The language HTML was modified many times leading to a number of versions, i.e. HTML version 0 to Version 5, which is the latest one.
HTML: It stands for Hyper Text Mark- up Language. HTML is a complete cod package that allows the user to create web pages. It includes text and graphics. We can add link to the web pages.
HYPER TEXT: Hypertext is the text used to link various web pages, which on clicking opens a new web page.
MARK - UP: It means highlighting the text either by underlying or displaying it different colors.
LANGUAGE: It refers to the way of communication between web pages, which has its own syntax and rules.
HTML Basic Tags and Their Attributes
An HTML document consists of text, which comprises the content of the document and tags, which define the structure and appearance of the document. The basic structure of an HTML document is simple with the entire document bound by a pair ofandtags.
HTML Document Structure:
Every HTML document should follow this general form:
<TITLE>Title of page is written here </TITLE>
<BODY>The HTML tags that define your page go here </BODY>
WHAT IS SERIES COMPLETION?
A series made up of alphabetical letters or numerals or combination of both may have one or more terms missing, one term wrong etc.
You have to find out the missing term(s) or identify the wrong term in the question from the given options.
Trick: To solve such problems first identify the rule on which the given series has been generated.
To Find out Missing Term(s)
In these type of questions, a series is given in which one or more terms are missing usually marked with '?'.
You have to find out the right option by identifying the rule to continue the series.
1. Find out the missing term marked with '?'.
(a) 95 (b) 106 (c) 62 (d) 102
We observe that,
The pattern is +11, +22, +33, + 44
So, 5th term = 44 + 4th term = 44 + 62 =
2. Find out the missing terms each marked with (?) in the series given below.
B, C, ?, H, L, ?, W
(a) E, Q (b) D, N (c) E, M (d) D, Q
3. Find out the missing term to replace the mark '?'.
hlp, txb, fjn, rvz, ?
(a) aei (b) cgk (c) dhl (d) dfh
In each term, there is a gap of 3 letters between any two consecutive letters.
Also there is a gap of 3 letters between the last letter of a term and the first letter of the next term.
4. Find out the missing letters in alphabetical series given below.
(a) abcabc (b) abbcca (c) ccbbaa (d) aabbcc
The complete given series is bca/bca/bca/bca/bca. Clearly, the pattern bca is repeated.
5. Find out the missing term.
H4J, ?, F9N, E13P, D18R
(a) I5K (b) G6L (c) MOL (d) T7Z
To Find Out Wrong Term
In this type of questions, a series is given of which one term does not follow the rule on which the series has been generated. You have to find out such term from the alternatives followed by the question.
6. Find the wrong term in the given series.
2, 4, 16, 32, 128,250, 1024
(a) 16 (b) 128 (c) 250 (d) 1024
The correct pattern more...
·This chapter deals with problems of the following types:
·Formation of a figure from its various components.
·Formation of 3-Dimensional figure from its net.
·Choosing an identical figure.
Choosing a pattern with identical components.
Find out which one of the four alternative figures can be formed from the pieces in the given Fig. (X).
(A) (B) (c) (D)
Joining the four pieces in Fig. (X), we get the following figure:
CONSTRUCTION OF SQUARES & TRIANGLES
In such type of problems, various, actual and fictitious parts of a square or a triangle are given. A student is required to form a square or a triangle in accordance the manner directed.
To construct a square select a piece which contains a right angle between two adjacent outer edges.
Try to fit other pieces into its hollow spaces.
If no square is constructed select another such piece and proceed the same.
Select that combination of the parts P, Q, R, S and T which can form a square when they are fitted into each other.
(a) QRT (b) PST (c) QRS (d) PRS