From Wikipedia, the free encyclopedia
Computer software, or just software is a general term used to describe a collection of computer programs, procedures and documentation that perform some tasks on a computer system.[1]
The term includes:
- Application software such as word processors which perform productive tasks for users.
- Firmware which is software programmed resident to electrically programmable memory devices on board mainboards or other types of integrated hardware carriers.
- Middleware which controls and co-ordinates distributed systems.
- System software such as operating systems, which interface with hardware to provide the necessary services for application software.
- Software Testing is a domain independent of development and programming, It consists various methods to test and declare a software product fit before it can be launched for use by either an indivudual or a group. Many tests on functionality, performance and appearance are conducted by modern testers with various tools such as QTP, Load runner, Black box testing etc to edit a checklist of requirements against the developed code. ISTQB is a certification that is in demand for engineers who want to pursue a career in testing.[2]
- Testware which is an umbrella term or container term for all utilities and application software that serve in combination for testing asoftware package but not necessarily may optionally contribute to operational purposes. As such, testware is not a standing configuration but merely a working environment for application software or subsets thereof.
Software includes websites, programs, video games etc. that are coded by programming languages like C, C++, etc.
"Software" is sometimes used in a broader context to mean anything which is not hardware but which is used with hardware, such as film, tapes and records.[3]
Overview
Computer software are often regarded as anything but hardware, meaning that the "hard" are the parts that are tangible while the "soft" part is the intangible objects inside the computer. Software encompasses an extremely wide array of products and technologies developed using different techniques like programming languages, scripting languages or even microcode or a FPGA state. The types of software include web pages developed by technologies like HTML, PHP, Perl, JSP, ASP.NET, XML, and desktop applications like Microsoft Word, OpenOffice developed by technologies like C, C++, Java, C#, etc. Software usually runs on an underlying operating system (which is software) such as Microsoft Windows, or Linux. Software also includes video games and the logic systems of modern consumer devices such as automobiles, televisions, toasters, etc.
Relationship to computer hardware
Computer software is so called to distinguish it from computer hardware, which encompasses the physical interconnections and devices required to store and execute (or run) the software. At the lowest level, software consists of a machine language specific to an individual processor. A machine language consists of groups of binary values signifying processor instructions which change the state of the computer from its preceding state. Software is an ordered sequence of instructions for changing the state of the computer hardware in a particular sequence. It is usually written in high-level programming languages that are easier and more efficient for humans to use (closer to natural language) than machine language. High-level languages are compiled or interpreted into machine language object code. Software may also be written in an assembly language, essentially, a mnemonic representation of a machine language using a natural language alphabet. Assembly language must be assembled into object code via an assembler.
The term "software" was first used in this sense by John W. Tukey in 1958.[4] In computer science and software engineering, computer software is all computer programs. The theory that is the basis for most modern software was first proposed by Alan Turing in his 1935 essay Computable numbers with an application to the Entscheidungsproblem.[5]
Types of software
Practical computer systems divide software systems into three major classes: system software, programming software and application software, although the distinction is arbitrary, and often blurred.
System software
System software helps run the computer hardware and computer system. It includes:
(these things need not be distinct)
The purpose of systems software is to unburden the applications programmer from the details of the particular computer complex being used, including such accessory devices as communications, printers, readers, displays, keyboards, etc. And also to partition the computer's resources such as memory and processor time in a safe and stable manner.
Programming software
Programming software usually provides tools to assist a programmer in writing computer programs, and software using different programming languages in a more convenient way. The tools include:
An Integrated development environment (IDE) is a single application that attempts to manage all these functions.
Application software
Application software allows end users to accomplish one or more specific (not directly computer development related) tasks. Typical applications include:
- industrial automation,
- business software,
- computer games,
- telecommunications, (ie the internet and everything that flows on it)
- databases,
- educational software,
- medical software,
Application software exists for and has impacted a wide variety of topics.
Software topics
Architecture
- See also: Software architecture
Users often see things differently than programmers. People who use modern general purpose computers (as opposed to embedded systems, analog computers, supercomputers, etc.) usually see three layers of software performing a variety of tasks: platform, application, and user software.
- Platform software: Platform includes the firmware, device drivers, an operating system, and typically a graphical user interface which, in total, allow a user to interact with the computer and its peripherals (associated equipment). Platform software often comes bundled with the computer. On a PC you will usually have the ability to change the platform software.
- Application software: Application software or Applications are what most people think of when they think of software. Typical examples include office suites and video games. Application software is often purchased separately from computer hardware. Sometimes applications are bundled with the computer, but that does not change the fact that they run as independent applications. Applications are almost always independent programs from the operating system, though they are often tailored for specific platforms. Most users think of compilers, databases, and other "system software" as applications.
- User-written software: End-user development tailors systems to meet users' specific needs. User software include spreadsheet templates, word processor macros, scientific simulations, and scripts for graphics and animations. Even email filters are a kind of user software. Users create this software themselves and often overlook how important it is. Depending on how competently the user-written software has been integrated into default application packages, many users may not be aware of the distinction between the the original packages, and what has been added by co-workers.
Documentation
Most software has software documentation so that the end user can understand the program, what it does and how to use it. Without a clear documentation a software can be hard to use and especially if it is a very specialized and relatively complex software like the Photoshop, AutoCAD, etc.
Developer documentation may also exist, either with the code as comments and/or as separate files, detailing how the programs works and can be modified.
Library
A executable is almost always not sufficiently complete for direct execution. Software libraries include collections of functions and functionality that may be embedded in other applications. Operating systems include many standard Software libraries, and applications are often distributed with their own libraries.
Execution
Computer software has to be "loaded" into the computer's storage (such as a hard drive, memory, or RAM). Once the software has loaded, the computer is able to execute the software. This involves passing instructions from the application software, through the system software, to the hardware which ultimately receives the instruction as machine code. Each instruction causes the computer to carry out an operation -- moving data, carrying out a computation, or altering the control flow of instructions.
Data movement is typically from one place in memory to another. Sometimes it involves moving data between memory and registers which enable high-speed data access in the CPU. Moving data, especially large amounts of it, can be costly. So, this is sometimes avoided by using "pointers" to data instead. Computations include simple operations such as incrementing the value of a variable data element. More complex computations may involve many operations and data elements together.
Quality and reliability
Software quality is very important, especially for commercial and system software like Microsoft Office, Microsoft Windows, Linux, etc. If software is faulty (buggy), it can delete a person's work, crash the computer and do other unexpected things. Faults and errors are called "bugs". Many bugs are discovered and eliminated (debugged) through software testing. However, software testing rarely -- if ever -- eliminates every bug; some programmers say that "every program has at least one more bug" (Lubarsky's Law). All major software companies, such as Microsoft, Novell and Sun Microsystems, have their own software testing departments with the specific goal of just testing. Software can be tested through unit testing, regression testing and other methods, which are done manually, or most commonly, automatically, since the amount of code to be tested can be quite large. For instance, NASA has extremely rigorous software testing procedures for its Space Shuttle and other programs because faulty software can crash the whole program and make the vehicle not functional, at great expense.
License
The software's license gives the user the right to use the software in the licensed environment. Some software comes with the license when purchased off the shelf, or an OEM license when bundled with hardware. Other software comes with a free software license, granting the recipient the rights to modify and redistribute the software. Software can also be in the form of freeware or shareware. See also License Management.
Patents
Software can be patented; however software patents can be controversial in the software industry with many people holding different views about it. Some believe that they hinder software development, while others argue that software patents provide an important incentive to spur software innovation. See software patent debate. The controversy over software patents is that a specific algorithm or technique that the software has cannot be duplicated by others and is considered an intellectual property and copyright infringement depending on the severity.
Ethics and rights
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There is more than one approach to creating, licensing, and distributing software. For instance, the free software or the open source community produces software under licensing that makes it free for inspection of its code, modification of its code, and distribution. While the software released under an open source license (such as General Public License, or GPL for short) can be sold for money[6], the distribution cannot be restricted in the same way as software with copyright and patent restrictions (used by corporations to require licensing fees).
While some advocates of free software use slogans such as "information wants to be free," hinting that it is easy to copy digital data and that the licenses (enforced through laws) are unnatural restrictions, other creators and users of open source software recognize it to be one model among many for software creation, licensing, and distribution. And the laws themselves are put into place for the ostensible purpose of increasing creative output, by allowing the creators to control and profit most effectively from their intellectual property.
Industry and organizations
There are many software companies in the world and selling software can be quite profitable industry. For instance, Bill Gates, the founder of Microsoft is the second richest man in the world in 2008 largely by selling the Microsoft Windows and Microsoft Office software programs, and same goes for Larry Ellison largely through his Oracle database software.
There are many non-profit software organizations like the Free Software Foundation, GNU Project, Mozilla Foundation. Also there are many software standards organizations like the W3C and others that try to come up with a software standard so that many software can work and interoperate with each other like through standards such as XML, HTML, HTTP, FTP, etc.
Some large software companies include Microsoft, IBM, Oracle, SAP and HP.[9]
- ^ "Wordreference.com: WordNet 2.0". Princeton University, Princeton, NJ. http://www.wordreference.com/definition/software. Retrieved on 2007-08-19.
- ^ The Complete Software testing Theory, Rao.Vinayak 2008 MBA Test Engineer
- ^ software..(n.d.). Dictionary.com Unabridged (v 1.1). Retrieved 2007-04-13, from Dictionary.com website: http://dictionary.reference.com/browse/software
- ^ "John Tukey, 85, Statistician; Coined the Word 'Software'". New York Times. 2000-07-28. http://query.nytimes.com/gst/fullpage.html?res=9500E4DA173DF93BA15754C0A9669C8B63.
- ^ Hally, Mike (2005:79). Electronic brains/Stories from the dawn of the computer age. British Broadcasting Corporation and Granta Books, London. ISBN 1-86207-663-4.
- ^ GNU project: "Selling Free Software": "we encourage people who redistribute free software to charge as much as they wish or can."
- ^ v. Engelhardt, Sebastian (2008): "The Economic Properties of Software", Jena Economic Research Papers, Volume 2 (2008), Number 2008-045. (in Adobe pdf format)
- ^ "Why Open Source Is The Optimum Economic Paradigm for Software" by Dan Kaminsky 1999
- ^ "Software Top 100: the world's largest software companies". the Top 100 research foundation. http://www.softwaretop100.org. Retrieved on 2008-04-28.
See also
