System software is computer software designed to operate the computer hardware and to provide and maintain a platform for running application software.
The most important types of system software are:
In some publications, the term system software is also used to designate software development tools (like a compiler, linker or debugger).
System software is usually not what a user would buy a computer for - instead, it can be seen as the basics of a computer which come built-in or pre-installed. In contrast to system software, software that allows users to do things like create text documents, play games, listen to music, or surf the web is called application software.
System software helps use the operating system and computer system. It includes diagnostic tools, compilers, servers, windowing systems, utilities, language translator, data communication programs, data management programs and more. The purpose of system software is to insulate the applications programmer as much as possible from the details of the particular computer complex being used, especially memory and other hardware features, and such accessory devices as communications, printers, readers, displays, keyboards, etc.
Specific kinds of system software include:
If system software is stored on non-volatile memory such as integrated circuits, it is usually termed firmware.
System software helps run the computer hardware and computer system. It includes a combination of the following:
Device Driver
In computing, a device driver or software driver is a computer program allowing higher-level computer programs to interact with a hardware device.
A driver typically communicates with the device through the computer bus or communications subsystem to which the hardware connects. When a calling program invokes a routine in the driver, the driver issues commands to the device. Once the device sends data back to the driver, the driver may invoke routines in the original calling program. Drivers are hardware-dependent and operating-system-specific. They usually provide the interrupt handling required for any necessary asynchronous time-dependent hardware interface.
Operating Systems
In computing, an operating system (OS) is an interface between hardware and user, which is responsible for the management and coordination of activities and the sharing of the resources of a computer, that acts as a host for computing applications run on the machine. One of the purposes of an operating system is to handle the resource allocation and access protection of the hardware. This relieves the application programmers from having to manage these details.
Operating systems offer a number of services to application programs and users. Applications access these services through application programming interfaces (APIs) or system calls. By invoking these interfaces, the application can request a service from the operating system, pass parameters, and receive the results of the operation. Users may also interact with the operating system with some kind of software user interface like typing commands by using command line interface (CLI) or using a graphical user interface. For hand-held and desktop computers, the user interface is generally considered part of the operating system. On large systems such as Unix-like systems, the user interface is generally implemented as an application program that runs outside the operating system.
While servers generally run Unix or some Unix-like operating system, embedded system markets are split amongst several operating systems, although the Microsoft Windows line of operating systems has almost 90% of the client PC market.
Server
In computing, a server is any combination of hardware or software designed to provide services to clients. When used alone, the term typically refers to a computer which may be running a server operating system, but is also used to refer to any software or dedicated hardware capable of providing services.
Utility Software
Utility software is a kind of
system software designed to help analyze, configure, optimize and maintain the computer. A single piece of utility software is usually called a
utility or
tool.
Utility software should be contrasted with application software, which allows users to do things like creating text documents, playing games, listening to music or surfing the web. Rather than providing these kinds of user-oriented or output-oriented functionality, utility software usually focuses on how the computer infrastructure (including the computer hardware, operating system, application software and data storage) operates. Due to this focus, utilities are often rather technical and targeted at people with an advanced level of computer knowledge.
Most utilities are highly specialized and designed to perform only a single task or a small range of tasks. However, there are also some utility suites that combine several features in one software.
Most major operating systems come with several pre-installed utilities.
Windowing SystemA windowing system (or window system) is a component of a graphical user interface (GUI), and more specifically of a desktop environment, which supports the implementation of window managers, and provides basic support for graphics hardware, pointing devices such as mice, and keyboards. The mouse cursor is also generally drawn by the windowing system.
The term windowing system is sometimes used to refer to other elements of a graphical interface such as those belonging to window managers or even applications. While on some operating systems the distinction between applications, window managers, and their supporting technologies are blurred, strictly speaking, a windowing system does not include windows themselves.
From a programmer's point of view, a windowing system implements graphical primitives such as rendering fonts or drawing a line on the screen, effectively providing an abstraction of the graphics hardware from higher level elements of the graphical interface like window managers.
A windowing system enables the computer user to work with several programs at the same time. Each program runs in its own window, which is generally a rectangular area of the screen. Most windowing systems have basic support of re-parenting which allows windows to overlap, however the ways in which windows interact is usually controlled by the window manager.
Some windowing systems, like the X Window System, have advanced capabilities such as network transparency, allowing the user to display graphical applications running on a remote machine. The X Window System takes a strictly layered approach, and does not implement any specific policy regarding the look and feel of the graphical user interfaces, and their behaviour, leaving that to the X window managers, widget toolkits and desktop environments.
Programming Software
A programming tool or software development tool is a program or application that software developers use to create, debug, maintain, or otherwise support other programs and applications. The term usually refers to relatively simple programs that can be combined together to accomplish a task, much as one might use multiple hand tools to fix a physical object.
Complier
A compiler is a computer program (or set of programs) that transforms source code written in a computer language (the source language) into another computer language (the target language, often having a binary form known as object code). The most common reason for wanting to transform source code is to create an executable program.
The name "compiler" is primarily used for programs that translate source code from a high-level programming language to a lower level language (e.g., assembly language or machine code). A program that translates from a low level language to a higher level one is a decompiler. A program that translates between high-level languages is usually called a language translator, source to source translator, or language converter. A language rewriter is usually a program that translates the form of expressions without a change of language.
A compiler is likely to perform many or all of the following operations: lexical analysis, preprocessing, parsing, semantic analysis, code generation, and code optimization.
Program faults caused by incorrect compiler behavior can be very difficult to track down and work around and compiler implementors invest a lot of time ensuring the correctness of their software.
The term compiler-compiler is sometimes used to refer to a parser generator, a tool often used to help create the lexer and parser.
Debuggers
A debugger or debugging tool is a computer program that is used to test and debug other programs (the "target" program). The code to be examined might alternatively be running on an instruction set simulator (ISS), a technique that allows great power in its ability to halt when specific conditions are encountered but which will typically be somewhat slower than executing the code directly on the appropriate (or the same) processor. Some debuggers offer two modes of operation - full or partial simulation, to limit this impact.
When the program "crashes" or reaches a preset condition, the debugger typically shows the position in the original code if it is a source-level debugger or symbolic debugger, commonly now seen in integrated development environments. If it is a low-level debugger or a machine-language debugger it shows the line in the disassembly (unless it also has online access to the original source code and can display the appropriate section of code from the assembly or compilation).(A "crash" happens when the program cannot normally continue because of a programming bug. For example, perhaps the program tried to use an instruction not available on the current version of the CPU or attempted access to unavailable or protected memory.)
Typically, debuggers also offer more sophisticated functions such as running a program step by step (single-stepping or program animation), stopping (breaking) (pausing the program to examine the current state) at some event or specified instruction by means of a breakpoint, and tracking the values of some variables. Some debuggers have the ability to modify the state of the program while it is running, rather than merely to observe it. It may also be possible to continue execution at a different location in the program to bypass a crash or logical error.
The importance of a good debugger cannot be overstated. Indeed, the existence and quality of such a tool for a given language and platform can often be the deciding factor in its use, even if another language/platform is better-suited to the task.[citation needed]. The absence of a debugger, having once been accustomed to using one, has been said to "make you feel like a blind man in a dark room looking for a black cat that isn’t there*"[1] However, software can (and often does) behave differently running under a debugger than normally, due to the inevitable changes the presence of a debugger will make to a software program's internal timing. As a result, even with a good debugging tool, it is often very difficult to track down runtime problems in complex multi-threaded or distributed systems.
The same functionality which makes a debugger useful for eliminating bugs allows it to be used as a software cracking tool to evade copy protection, digital rights management, and other software protection features. It often also makes it useful as a general testing verification tool test coverage and performance analyzer, especially if instruction path lengths are shown.
Most current mainstream debugging engines, such as gdb and dbx provide console-based command line interfaces. Debugger front-ends are popular extensions to debugger engines that provide IDE integration, program animation, and visualization features. Some early mainframe debuggers such as Oliver and SIMON provided this same functionality for the IBM System/360 and later operating systems, as long ago as the 1970s.
Interpreters
In computer science, an interpreter normally means a computer program that executes, i.e. performs, instructions written in a programming language. An interpreter may be a program that either
- executes the source code directly
- translates source code into some efficient intermediate representation (code) and immediately executes this
- explicitly executes stored precompiled code made by a compiler which is part of the interpreter system
Perl, Python, MATLAB, and Ruby are examples of type 2, while UCSD Pascal and Java are type 3: Source programs are compiled ahead of time and stored as machine independent code, which is then linked at run-time and executed by an interpreter and/or compiler (for JIT systems). Some systems, such as Smalltalk, and others, may also combine 2 and 3.
While interpretation and compilation are the two principal means by which programming languages are implemented, these are not fully distinct categories, one of the reasons being that most interpreting systems also perform some translation work, just like compilers. The terms interpreted language or compiled language merely mean that the canonical implementation of that language is an interpreter or a compiler; a high level language is basically an abstraction which is (ideally) independent of particular implementations.
Linkers
In computer science, a linker or link editor is a program that takes one or more objects generated by a compiler and combines them into a single executable program.
In IBM mainframe environments such as OS/360 this program is known as a linkage editor.
On Unix variants the term loader is often used as a synonym for linker. Because this usage blurs the distinction between the compile-time process and the run-time process, this article will use linking for the former and loading for the latter. However, in some operating systems the same program handles both the jobs of linking and loading a program; see dynamic linking.
Text Editors
A text editor is a type of program used for editing plain text files.
Text editors are often provided with operating systems or software development packages, and can be used to change configuration files and programming language source code.
Application Software
Application software is computer software designed to help the user to perform a singular or multiple related specific tasks. Such programs are also called software applications, applications or apps. Typical examples are word processors, spreadsheets, media players and database applications.
Application software should be contrasted with system software (infrastructure) or middleware (computer services/ processes integrators), which is involved in integrating a computer's various capabilities, but typically does not directly apply them in the performance of tasks that benefit the user. A simple, if imperfect analogy in the world of hardware would be the relationship of an electric light bulb (an application) to an electric power generation plant (a system). The power plant merely generates electricity, not itself of any real use until harnessed to an application like the electric light that performs a service that benefits the user.
Industrial Automation
Automation is the use of control systems (such as numerical control, programmable logic control, and other industrial control systems), in concert with other applications of information technology (such as computer-aided technologies [CAD, CAM, CAx]), to control industrial machinery and processes, reducing the need for human intervention. In the scope of industrialization, automation is a step beyond mechanization. Whereas mechanization provided human operators with machinery to assist them with the muscular requirements of work, automation greatly reduces the need for human sensory and mental requirements as well. Processes and systems can also be automated.
Automation plays an increasingly important role in the world economy and in daily experience. Engineers strive to combine automated devices with mathematical and organizational tools to create complex systems for a rapidly expanding range of applications and human activities.
Many roles for humans in industrial processes presently lie beyond the scope of automation. Human-level pattern recognition, language recognition, and language production ability are well beyond the capabilities of modern mechanical and computer systems. Tasks requiring subjective assessment or synthesis of complex sensory data, such as scents and sounds, as well as high-level tasks such as strategic planning, currently require human expertise. In many cases, the use of humans is more cost-effective than mechanical approaches even where automation of industrial tasks is possible.
Specialised hardened computers, referred to as programmable logic controllers (PLCs), are frequently used to synchronize the flow of inputs from (physical) sensors and events with the flow of outputs to actuators and events. This leads to precisely controlled actions that permit a tight control of almost any industrial process.
Human-machine interfaces (HMI) or computer human interfaces (CHI), formerly known as man-machine interfaces, are usually employed to communicate with PLCs and other computers, such as entering and monitoring temperatures or pressures for further automated control or emergency response. Service personnel who monitor and control these interfaces are often referred to as stationary engineers in boiler houeses or central utilities departments. In most industrial process and manufacturing environments, these roles are called operators or variations on this.
Business Software
Business software is generally any software program that helps a business increase productivity or measure their productivity. The term covers a large variation of uses within the business environment, and can be categorized by using a small, medium and large matrix:
- The small business market generally consists of home accounting software, and office suites such as Microsoft Office and OpenOffice.org.
- The medium size, or SME, has a broader range of software applications, ranging from accounting, groupware, customer relationship management, human resources software, outsourcing relationship management, loan origination software, shopping cart software, field service software, and other productivity enhancing applications.
- The last segment covers enterprise level software applications, such as those in the fields of enterprise resource planning, enterprise content management (ECM), business process management and product lifecycle management. These applications are extensive in scope, and often come with modules that either add native functions, or incorporate the functionality of third-party software programs.
Now, technologies that have previously only existed in peer-to-peer software applications, like Kazaa and Napster, are starting to feature within business applications. JXTA is an open source platform that enables the creation of machine and language neutral applications.
Video Games
A video game is an electronic game that involves interaction with a user interface to generate visual feedback on a video device. The word video in video game traditionally referred to a raster display device. However, with the popular use of the term "video game", it now implies any type of display device. The electronic systems used to play video games are known as platforms; examples of these are personal computers and video game consoles. These platforms range from large mainframe computers to small handheld devices. Specialized video games such as arcade games, while previously common, have gradually declined in use.
The input device used to manipulate video games is called a game controller, and varies across platforms. For example, a dedicated console controller might consist of only a button and a joystick. Another may feature a dozen buttons and one or more joysticks. Early personal computer games often needed a keyboard for gameplay, or more commonly, required the user to buy a separate joystick with at least one button. Many modern computer games allow, or even require, the player to use a keyboard and mouse simultaneously.
Video games typically also use other ways of providing interaction and information to the player. Audio is almost universal, using sound reproduction devices, such as speakers and headphones. Other feedback may come via haptic peripherals, such as vibration or force feedback, with vibration sometimes used to simulate force feedback.
Telecommunication
Telecommunication is the transmission of signals over a distance for the purpose of communication. In earlier times, this may have involved the use of smoke signals, drums, semaphore, flags or heliograph. In modern times, telecommunication typically involves the use of electronic devices such as telephones, television, radio or computers. Early inventors in the field of telecommunication include Alexander Graham Bell, Jagdish Bose Chandra, Guglielmo Marconi and John Logie Baird. Telecommunication is an important part of the world economy and the telecommunication industry's revenue was estimated to be $1.2 trillion in 2006.
Database
A database is an integrated collection of logically-related records or files consolidated into a common pool that provides data for one or more multiple uses. One way of classifying databases involves the type of content, for example: bibliographic, full-text, numeric, image. Other classification methods start from examining database models or database architectures: see below. Software organizes the data in a database according to a database model. As of 2010[update] the relational model occurs most commonly. Other models such as the hierarchical model and the network model use a more explicit representation of relationships.
Educational Software
Educational software is computer software, the primary purpose of which is teaching or self-learning.
Image Editing
Image editing encompasses the processes of altering images, whether they be digital photographs, traditional analog photographs, or illustrations. Traditional analog image editing is known as photo retouching, using tools such as an airbrush to modify photographs, or editing illustrations with any traditional art medium. Graphic software programs, which can be broadly grouped into vector graphics editors, raster graphics editors, and 3d modelers, are the primary tools with which a user may manipulate, enhance, and transform images. Many image editing programs are also used to render or create computer art from scratch.
Simulations Software
Simulation software is based on the process of imitating a real phenomenon with a set of mathematical formulas. It is, essentially, a program that allows the user to observe an operation through simulation without actually performing that operation. Simulation software is used widely to design equipment so that the final product will be as close to design specs as possible without expensive in process modification. Simulation software with real-time response is often used in gaming, but it also has important industrial applications. When the penalty for improper operation is costly, such as airplane pilots, nuclear power plant operators, or chemical plant operators, a mock up of the actual control panel is connected to a real-time simulation of the physical response, giving valuable training experience without fear of a disastrous outcome.
Advanced computer programs can simulate weather conditions, electronic circuits, chemical reactions, mechatronics, heat pumps, feedback control systems, atomic reactions, even biological processes. In theory, any phenomena that can be reduced to mathematical data and equations can be simulated on a computer. Simulation can be difficult because most natural phenomena are subject to an almost infinite number of influences. One of the tricks to developing useful simulations is to determine which are the most important factors that affect the goals of the simulation.
In addition to imitating processes to see how they behave under different conditions, simulations are also used to test new theories. After creating a theory of causal relationships, the theorist can codify the relationships in the form of a computer program. If the program then behaves in the same way as the real process, there is a good chance that the proposed relationships are correct.
(The little cutie in red popping out of the fountain slabs)
