Software engineering

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The new Airbus A-380 uses a substantial amount of software to create a "paperless" cockpit.

A typical software engineer's office.

Software engineering is the application of a systematic, disciplined, quantifiable approach to the development, operation, and maintenance of software, and the study of these approaches. That is the application of engineering to software. [1]

The term software engineering first appeared in the 1968 NATO Software Engineering Conference and was meant to provoke thought regarding the current "software crisis" at the time.[2] Since then, it has continued as a profession and field of study dedicated to creating software that is of higher quality, cheaper, maintainable, and quicker to build. Since the field is still relatively young compared to its sister fields of engineering, there is still much work and debate around what software engineering actually is. It has grown organically out of the limitations of viewing software as just programming. Software development is a term sometimes preferred by practitioners in the industry who view software engineering as too heavy-handed and constrictive to the malleable process of creating software.

Yet, in spite of its youth as a profession, the field's future looks bright as Money Magazine and Salary.com rated software engineering as the best job in America in 2006. [3]

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Computer virus

A computer virus is a computer program that can copy itself and infect a computer without permission or knowledge of the user. The term "virus" is also commonly used, albeit erroneously, to refer to many different types of malware and adware programs. The original virus may modify the copies, or the copies may modify themselves, as occurs in a metamorphic virus. A virus can only spread from one computer to another when its host is taken to the uninfected computer, for instance by a user sending it over a network or the Internet, or by carrying it on a removable medium such as a floppy disk, CD, or USB drive. Meanwhile viruses can spread to other computers by infecting files on a network file system or a file system that is accessed by another computer. Viruses are sometimes confused with computer worms and Trojan horses. A worm can spread itself to other computers without needing to be transferred as part of a host, and a Trojan horse is a file that appears harmless. Worms and Trojans may cause harm to either a computer system's hosted data, functional performance, or networking throughput, when executed. In general, a worm does not actually harm either the system's hardware or software, while at least in theory, a Trojan's payload may be capable of almost any type of harm if executed. Some can't be seen when the program is not running, but as soon as the infected code is run, the Trojan horse kicks in. That is why it is so hard for people to find viruses and other malware themselves and why they have to use anti-spyware programs and registry processors.

Most personal computers are now connected to the Internet and to local area networks, facilitating the spread of malicious code. Today's viruses may also take advantage of network services such as the World Wide Web, e-mail, Instant Messaging and file sharing systems to spread, blurring the line between viruses and worms. Furthermore, some sources use an alternative terminology in which a virus is any form of self-replicating malware.

Some malware is programmed to damage the computer by damaging programs, deleting files, or reformatting the hard disk. Other malware programs are not designed to do any damage, but simply replicate themselves and perhaps make their presence known by presenting text, video, or audio messages. Even these less sinister malware programs can create problems for the computer user. They typically take up computer memory used by legitimate programs. As a result, they often cause erratic behavior and can result in system crashes. In addition, much malware is bug-ridden, and these bugs may lead to system crashes and data loss.

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The World Wide Web

Graphic representation of a minute fraction of the WWW, demonstrating hyperlinks

For more details on this topic, see World Wide Web.

Graphic representation of a minute fraction of the WWW, demonstrating hyperlinks

Many people use the terms Internet and World Wide Web (or just the Web) interchangeably, but, as discussed above, the two terms are not synonymous.

The World Wide Web is a huge set of interlinked documents, images and other resources, linked by hyperlinks and URLs. These hyperlinks and URLs allow the web servers and other machines that store originals, and cached copies of, these resources to deliver them as required using HTTP (Hypertext Transfer Protocol). HTTP is only one of the communication protocols used on the Internet.

Web services also use HTTP to allow software systems to communicate in order to share and exchange business logic and data.

Software products that can access the resources of the Web are correctly termed user agents. In normal use, web browsers, such as Internet Explorer, Firefox and Apple Safari, access web pages and allow users to navigate from one to another via hyperlinks. Web documents may contain almost any combination of computer data including graphics, sounds, text, video, multimedia and interactive content including games, office applications and scientific demonstrations.

Through keyword-driven Internet research using search engines like Yahoo! and Google, millions of people worldwide have easy, instant access to a vast and diverse amount of online information. Compared to encyclopedias and traditional libraries, the World Wide Web has enabled a sudden and extreme decentralization of information and data.

Using the Web, it is also easier than ever before for individuals and organisations to publish ideas and information to an extremely large audience. Anyone can find ways to publish a web page, a blog or build a website for very little initial cost. Publishing and maintaining large, professional websites full of attractive, diverse and up-to-date information is still a difficult and expensive proposition, however.

Many individuals and some companies and groups use "web logs" or blogs, which are largely used as easily updatable online diaries. Some commercial organisations encourage staff to fill them with advice on their areas of specialization in the hope that visitors will be impressed by the expert knowledge and free information, and be attracted to the corporation as a result. One example of this practice is Microsoft, whose product developers publish their personal blogs in order to pique the public's interest in their work.

Collections of personal web pages published by large service providers remain popular, and have become increasingly sophisticated. Whereas operations such as Angelfire and GeoCities have existed since the early days of the Web, newer offerings from, for example, Facebook and MySpace currently have large followings. These operations often brand themselves as social network services rather than simply as web page hosts.

Advertising on popular web pages can be lucrative, and e-commerce or the sale of products and services directly via the Web continues to grow.

In the early days, web pages were usually created as sets of complete and isolated HTML text files stored on a web server. More recently, websites are more often created using content management or wiki software with, initially, very little content. Contributors to these systems, who may be paid staff, members of a club or other organisation or members of the public, fill underlying databases with content using editing pages designed for that purpose, while casual visitors view and read this content in its final HTML form. There may or may not be editorial, approval and security syste

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The programmer subculture of hackers

Main article: Hacker (programmer subculture)

A Hacker Emblem proposed by Eric S. Raymond.

The computer security use is contrasted by the different understanding of hacker as a person who follows a spirit of playful cleverness and loves programming. It is found in an originally academic movement unrelated to computer security and most visibly associated with free software and open source. It also has a hacker ethic, based on the idea that writing software and sharing the result on a voluntary basis is a good idea, and that information should be free, but that it's not up to the hacker to make it free by breaking into private computer systems. Academic hackers disassociate from the mass media's pejorative use of the word 'hacker' referring to computer security, and usually prefer the term 'cracker' for that meaning.

In this hacker culture, a computer hacker is a person who enjoys designing software and building programs with a sense for aesthetics and playful cleverness. The term hack in this sense can be traced back to "describe the elaborate college pranks that...students would regularly devise" (Levy, 1984 p.10). To be considered a 'hack' was an honour among like-minded peers as "to qualify as a hack, the feat must be imbued with innovation, style and technical virtuosity" (levy, 1984 p.10)

According to Eric S. Raymond,^[21] the Open source and Free Software hacker subculture developed in the 1960s among ‘academic hackers’^[22] working on early minicomputers in computer science environments in the United States. After 1969 it fused with the technical culture of the pioneers of the Arpanet. The PDP-10 machine AI at MIT, which was running the ITS operating system and was connected to the Arpanet, provided an early hacker meeting point. After 1980 the subculture coalesced with the culture of Unix, and after 1987 with elements of the early microcomputer hobbyists that themselves had connections to radio amateurs in the 1920s. Since the mid-1990s, it has been largely coincident with what is now called the free software and open source movement.

Many programmers have been labeled "great hackers,"^[23] but the specifics of who that label applies to is a matter of opinion. Certainly major contributors to computer science such as Edsger Dijkstra and Donald Knuth, as well as the inventors of popular software such as Linus Torvalds (Linux), and Dennis Ritchie and Ken Thompson (the C programming language) are likely to be included in any such list; see also List of programmers. People primarily known for their contributions to the consciousness of the academic hacker culture include Richard Stallman, the founder of the free software movement and the GNU project, president of the Free Software Foundation and author of the famous Emacs text editor as well as the GNU Compiler Collection (GCC), and Eric S. Raymond, one of the founders of the Open Source Initiative and writer of the famous text The Cathedral and the Bazaar and many other essays, maintainer of the Jargon File (which was previously maintained by Guy L. Steele, Jr.).

Within the academic hacker culture, the term hacker is also used for a programmer who reaches a goal by employing a series of modifications to extend existing code or resources. In this sense, it can have a negative connotation of using kludges to accomplish programming tasks that are ugly, inelegant, and inefficient. This derogatory form of the noun "hack" is even used among users of the positive sense of "hacker" (some argue that it should not be, due to this negative meaning; others argue that some kludges can, for all their ugliness and imperfection, still have "hack value"). In a very universal sense, hacker also means someone who makes things work beyond perceived limits in a clever way in general.^[4] That is, people who apply the creative attitude of software hackers in fields other than computing. This includes even activities that predate computer hacking, for example reality hackers.^[24] More recent examples of this usage are wetware hackers and media hackers. According to the Jargon File the word hacker was used in a similar meaning among radio amateurs already in the 1950s.^[25]

The culture sometimes uses jargon which is "incomprehensible to outsiders".^[26] Examples are 'losing' "when a piece of equipment is not working"^[26] and 'munged' "when a piece of equipment is ruined".^[26]

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Computer Science Degrees & Resources Online

Introduction

Computer science is the overarching title attributed to the discipline of utilizing computation and information in computer systems. Whereas computer programmers create source code and use programming language to make software, the computer scientist uses these software applications for practical purposes and to understand and utilize computational systems.

Computer Science Books

To master computer science, you will have to do a lot of reading on the subject. While your specific program may recommend certain computer science books to you, you will do well to read as many of the best computer science books as you can get your hands on. Some good texts to start with include 'The C Programming Language' by Brian W. Kernighan, 'C++ Primer' by Stanley B. Lippman, 'Introduction to Algorithms' by Thomas H. Cormen, 'Introduction to the Theory of Computation' by Michael Sipser and 'Concrete Mathematics, a Foundation for Computer Science' by Ronald L. Graham. Places to find computer science books online include Amazon.com, FreeTechBooks.com and your school library website.

Computer Science Articles And Databases

A terrific source of computer science articles is the Citeseer.Continuity database. This database lists all the most cited articles in computer science from 2006 back to 1990, so you have a great chance of finding the article you need, whether it be for research, information or to verify a theory. The database, is updated on a regular basis.

Online Computer Science Journals

Of course, most of the key computer science articles will be found in leading computer science journals. There is no shortage of computer science journals out there, many of which may be accessible through your school libraryís web page, the web pages of other libraries or through other computer science resources online. Some of these include Artificial Intelligence, Computer Graphics, IEEE Transactions on Evolutionary Computation, the Journal of Web Semantics and Logical Methods in Computer Science.

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History of Computer

A computer is a machine that manipulates data according to a list of instructions.

The first devices that resemble modern computers date to the mid-20th century (1940–1945), although the computer concept and various machines similar to computers existed earlier. Early electronic computers were the size of a large room, consuming as much power as several hundred modern personal computers(PC). Modern computers are based on tiny integrated circuits and are millions to billions of times more capable while occupying a fraction of the space. Today, simple computers may be made small enough to fit into a wristwatch and be powered from a watch battery. Personal computers, in various forms, are icons of the Information Age and are what most people think of as "a computer"; however, the most common form of computer in use today is the embedded computer. Embedded computers are small, simple devices that are used to control other devices — for example, they may be found in machines ranging from fighter aircraft to industrial robots, digital cameras, and children's toys.

The ability to store and execute lists of instructions called programs makes computers extremely versatile and distinguishes them from calculators. The Church–Turing thesis is a mathematical statement of this versatility: any computer with a certain minimum capability is, in principle, capable of performing the same tasks that any other computer can perform. Therefore, computers with capability and complexity ranging from that of a personal digital assistant to a supercomputer are all able to perform the same computational tasks given enough time and storage capacity.

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Tracking the IP address

1. Tracking the IP address of a site
To know the IP address of a site, we can ping the site these. How: Go to the command prompt and typing PING WWW.SITUS-THE-DILACAK.COM and press enter. It will appear Ip address site these.

2. Track the location server (a real address) of a site
We can track the location of a server with only the site address the site only. You try to stay open www.domainwhitepages.com enter the IP address was the site or enter the address of the site and you will get info full on the server of these sites are the locations of countries and city.

3. Tracking the IP address opponent's chat
When we use Yahoo messenger, we can actually know the IP address from the opponent we chat. How:
:: Send a file on the opponent we chat.
:: Then go to the Command Prompt (MSDOS) and N-type NETSTAT and press
enter, then the IP address of your opponent chats (which you have the file was sent)
will appear along with the port used for sending files.
:: To know the location of your opponent chat (real address) as it is
on campus or in the cafe where you live in check www.domainwhitepages.com
using the IP address that you get.

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