1.
Command-line interface
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A program which handles the interface is called a command language interpreter or shell. The interface is implemented with a command line shell, which is a program that accepts commands as text input. Command-line interfaces to computer operating systems are widely used by casual computer users. Alternatives to the line include, but are not limited to text user interface menus, keyboard shortcuts. Examples of this include the Windows versions 1,2,3,3.1, and 3.11, DosShell, and Mouse Systems PowerPanel. Command-line interfaces are preferred by more advanced computer users, as they often provide a more concise. Programs with command-line interfaces are generally easier to automate via scripting, a program that implements such a text interface is often called a command-line interpreter, command processor or shell. Under most operating systems, it is possible to replace the shell program with alternatives, examples include 4DOS for DOS, 4OS2 for OS/2. For example, the default Windows GUI is a program named EXPLORER. EXE. These programs are shells, but not CLIs, application programs may also have command line interfaces. When a program is launched from an OS command line shell, interactive command line sessions, After launch, a program may provide an operator with an independent means to enter commands in the form of text. OS inter-process communication, Most operating systems support means of inter-process communication, Command lines from client processes may be redirected to a CLI program by one of these methods. Some applications support only a CLI, presenting a CLI prompt to the user, Some examples of CLI-only applications are, DEBUG Diskpart Ed Edlin Fdisk Ping Some computer programs support both a CLI and a GUI. In some cases, a GUI is simply a wrapper around a separate CLI executable file, in other cases, a program may provide a CLI as an optional alternative to its GUI. CLIs and GUIs often support different functionality, for example, all features of MATLAB, a numerical analysis computer program, are available via the CLI, whereas the MATLAB GUI exposes only a subset of features. The early Sierra games, like the first three Kings Quest games, used commands from a command line to move the character around in the graphic window. Early computer systems often used teleprinter machines as the means of interaction with a human operator, the computer became one end of the human-to-human teleprinter model. So instead of a human communicating with another human over a teleprinter, in time, the actual mechanical teleprinter was replaced by a glass tty, and then by a smart terminal
2.
File manager
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A file manager or file browser is a computer program that provides a user interface to manage files and folders. Folders and files may be displayed in a tree based on their directory structure. Some file managers contain features inspired by web browsers, including forward, some file managers provide network connectivity via protocols, such as FTP, NFS, SMB or WebDAV. This is achieved by allowing the user to browse for a server or by providing its own full client implementations for file server protocols. A term that predates the usage of file manager is directory editor, the term was used by other developers, including Jay Lepreau, who wrote the dired program in 1980, which ran on BSD. This was in inspired by an older program with the same name running on TOPS-20. Dired inspired other programs, including dired, the editor script, file-list file managers are lesser known and older than orthodox file managers. One such file manager is flist, which was first used in 1981 on the Conversational Monitor System and this is a variant of fulist, which originated before late 1978, according to comments by its author, Theo Alkema. The flist program provided a list of files in the users minidisk, the file attributes could be passed to scripts or function-key definitions, making it simple to use flist as part of CMS EXEC, EXEC2 or XEDIT scripts. Orthodox file managers or command-based file managers are text-menu based file managers, Orthodox file managers are one of the longest running families of file managers, preceding Graphical User Interface-based types. Developers create applications that duplicate and extend the manager that was introduced by PathMinder, the concept is more than thirty years old—PathMinder was released in 1984, and Norton Commander version 1.0 was released in 1986. Despite the age of this concept, file managers based on Norton Commander are actively developed, and dozens of implementations exist for DOS, Unix, Nikolai Bezroukov publishes his own set of criteria for an OFM standard. An orthodox file manager typically has three windows, two of the windows are called panels and are positioned symmetrically at the top of the screen. The third is the line, which is essentially a minimized command window that can be expanded to full screen. Only one of the panels is active at a given time, the active panel contains the file cursor. Panels are resizable and can be hidden, files in the active panel serve as the source of file operations performed by the manager. For example, files can be copied or moved from the panel to the location represented in the passive panel. This scheme is most effective for systems in which the keyboard is the primary or sole input device, the active panel shows information about the current working directory and the files that it contains
3.
Midnight Commander
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GNU Midnight Commander is a free cross-platform orthodox file manager. It was started by Miguel de Icaza in 1994 as a clone of the then popular Norton Commander, GNU Midnight Commander is part of the GNU project and is licensed under the terms of the GNU General Public License. Midnight Commander is an application with a text user interface. The main interface consists of two panels which display the file system, File selection is done using arrow keys, the insert key is used to select files and the function keys perform operations such as renaming, editing and copying files. Later versions of the Midnight Commander additionally have mouse support, such versions are aware of GPM and X terminal emulators which support mouse reporting. When running inside an X terminal, these versions can update the name of the window in which Midnight Commander runs, Midnight Commander also includes an editor called mcedit, which can be executed as a standalone program or from Midnight Commander using the F4 key. Users also have the option to replace mcedit with the editor of their choice, Midnight Commander can also rename groups of files, unlike a number of other file managers that can only rename one file at a time. This is convenient for manipulating large collections of files, e. g. to make them conform to a new naming convention, Midnight Commander can also move files to a different directory at the same time as it renames them. It lets the user specify the original and resulting file names using wildcard characters and this makes the power of regular expressions available for renaming files, with a convenient user interface. In addition, the user can select whether or not to use shell patterns or globs, all of these features are available by using the File > Rename/Move menu selection. Native support for UTF-8 locales for Unicode was added in 2009 to development versions of Midnight Commander, as of version 4.7.0, mc has had Unicode support
4.
Vim (text editor)
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Vim is a clone of Bill Joys vi text editor program for Unix. It was written by Bram Moolenaar based on source for a port of the Stevie editor to the Amiga, Vim is designed for use both from a command-line interface and as a standalone application in a graphical user interface. Vim is free and open software and is released under a license that includes some charityware clauses. The license is compatible with the GNU General Public License, although Vim was originally released for the Amiga, Vim has since been developed to be cross-platform, supporting many other platforms. Bram Moolenaar began working on Vim for the Amiga computer in 1988, Moolenaar first publicly released Vim in 1991. Vim was based on an editor, Stevie, for the Atari ST, created by Tim Thompson, Tony Andrews. The name Vim is an acronym for Vi IMproved because Vim is a version of the vi editor. Originally, the acronym stood for Vi IMitation, but that was changed with the release of Vim 2.0 in December 1993, a later comment states that the reason for changing the name was that Vims feature set surpassed that of vi. Vi tends to allow a typist to keep their fingers on the home row, Vim has a built-in tutorial for beginners. There is also the Vim Users Manual that details Vims features and this manual can be read from within Vim, or found online. Vim also has a built-in help facility that allows users to query and navigate through commands, part of Vims power is that it can be extensively customized. There are many available that will extend or add new functionality to Vim. These complex scripts are written in Vims internal scripting language. Vim also supports scripting using Lua, Perl, Python, Racket, Ruby, there are projects bundling together complex scripts and customizations and aimed at turning Vim into a tool for a specific task or adding a major flavour to its behaviour. Examples include Cream, which makes Vim behave like a click-and-type editor, or VimOutliner, Vim has a vi compatibility mode, but, when not in this mode, Vim has many enhancements over vi. However, even in compatibility mode, Vim is not entirely compatible with vi as defined in the Single Unix Specification, Vim has nevertheless been described as very much compatible with Vi. Vim script is the language built into Vim. Based on the ex editor language of the vi editor, early versions of Vim added commands for control flow
5.
Retronym
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A retronym is a neologism for a word created to differentiate between two words, where previously no clarification was required. Advances in technology are responsible for the coinage of retronyms. For example, the acoustic guitar was coined at the advent of electric guitars. Since the end of the 19th century, most bicycles have been expected to have two equal sized wheels, and the type has been renamed penny-farthing or high-wheeler bicycle. Similarly, the term cisgender was coined to describe persons who identify with the gender they were assigned at birth, the term retronym was coined by Frank Mankiewicz in 1980 and popularized by William Safire in The New York Times Magazine. In 2000 The American Heritage Dictionary became the first major dictionary to include the word retronym, back-formation Backronym Contrastive focus reduplication -onym Protologism
6.
Graphical user interface
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GUIs were introduced in reaction to the perceived steep learning curve of command-line interfaces, which require commands to be typed on a computer keyboard. The actions in a GUI are usually performed through direct manipulation of the graphical elements, beyond computers, GUIs are used in many handheld mobile devices such as MP3 players, portable media players, gaming devices, smartphones and smaller household, office and industrial controls. Designing the visual composition and temporal behavior of a GUI is an important part of application programming in the area of human–computer interaction. Its goal is to enhance the efficiency and ease of use for the logical design of a stored program. Methods of user-centered design are used to ensure that the language introduced in the design is well-tailored to the tasks. The visible graphical interface features of an application are sometimes referred to as chrome or GUI, typically, users interact with information by manipulating visual widgets that allow for interactions appropriate to the kind of data they hold. The widgets of an interface are selected to support the actions necessary to achieve the goals of users. A model–view–controller allows a structure in which the interface is independent from and indirectly linked to application functions. This allows users to select or design a different skin at will, good user interface design relates to users more, and to system architecture less. Large widgets, such as windows, usually provide a frame or container for the main presentation content such as a web page, smaller ones usually act as a user-input tool. A GUI may be designed for the requirements of a market as application-specific graphical user interfaces. By the 1990s, cell phones and handheld game systems also employed application specific touchscreen GUIs, newer automobiles use GUIs in their navigation systems and multimedia centers, or navigation multimedia center combinations. Sample graphical desktop environments A GUI uses a combination of technologies and devices to provide a platform that users can interact with, a series of elements conforming a visual language have evolved to represent information stored in computers. This makes it easier for people with few computer skills to work with, the most common combination of such elements in GUIs is the windows, icons, menus, pointer paradigm, especially in personal computers. The WIMP style of interaction uses a virtual device to represent the position of a pointing device, most often a mouse. Available commands are compiled together in menus, and actions are performed making gestures with the pointing device, a window manager facilitates the interactions between windows, applications, and the windowing system. The windowing system handles hardware devices such as pointing devices, graphics hardware, window managers and other software combine to simulate the desktop environment with varying degrees of realism. Smaller mobile devices such as personal assistants and smartphones typically use the WIMP elements with different unifying metaphors, due to constraints in space
7.
Computer graphics
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Computer graphics are pictures and films created using computers. Usually, the term refers to computer-generated image data created with help from specialized hardware and software. It is a vast and recent area in computer science, the phrase was coined in 1960, by computer graphics researchers Verne Hudson and William Fetter of Boeing. It is often abbreviated as CG, though sometimes referred to as CGI. The overall methodology depends heavily on the sciences of geometry, optics. Computer graphics is responsible for displaying art and image data effectively and meaningfully to the user and it is also used for processing image data received from the physical world. Computer graphic development has had a significant impact on many types of media and has revolutionized animation, movies, advertising, video games, the term computer graphics has been used a broad sense to describe almost everything on computers that is not text or sound. Such imagery is found in and on television, newspapers, weather reports, a well-constructed graph can present complex statistics in a form that is easier to understand and interpret. In the media such graphs are used to illustrate papers, reports, thesis, many tools have been developed to visualize data. Computer generated imagery can be categorized into different types, two dimensional, three dimensional, and animated graphics. As technology has improved, 3D computer graphics have become more common, Computer graphics has emerged as a sub-field of computer science which studies methods for digitally synthesizing and manipulating visual content. Screens could display art since the Lumiere brothers use of mattes to create effects for the earliest films dating from 1895. New kinds of displays were needed to process the wealth of information resulting from such projects, early projects like the Whirlwind and SAGE Projects introduced the CRT as a viable display and interaction interface and introduced the light pen as an input device. Douglas T. Ross of the Whirlwind SAGE system performed an experiment in 1954 in which a small program he wrote captured the movement of his finger. Electronics pioneer Hewlett-Packard went public in 1957 after incorporating the decade prior, and established ties with Stanford University through its founders. This began the transformation of the southern San Francisco Bay Area into the worlds leading computer technology hub - now known as Silicon Valley. The field of computer graphics developed with the emergence of computer graphics hardware, further advances in computing led to greater advancements in interactive computer graphics. In 1959, the TX-2 computer was developed at MITs Lincoln Laboratory, the TX-2 integrated a number of new man-machine interfaces
8.
Text mode
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Text mode is a computer display mode in which content is internally represented on a computer screen in terms of characters rather than individual pixels. Typically, the screen consists of a rectangular grid of character cells. Text mode is contrasted to all points addressable mode or other kinds of computer graphics modes, text mode applications communicate with the user with command-line interfaces and text user interfaces. A typical example is the IBM code page 437 character set and this was an analogy of early mechanical printers which had fixed pitch. This way, the output seen on the screen could be sent directly to the printer maintaining exactly the same format, depending on the environment, the screen buffer can be directly addressable. Programs that display output on remote video terminals must issue special control sequences to manipulate the screen buffer, the most popular standards for such control sequences are ANSI and VT100. Text mode video rendering came to prominence in the early 1970s, the advantages of text modes as compared to graphics modes include lower memory consumption and faster screen manipulation. Early framebuffers were standalone devices which cost thousands of dollars, in addition to the expense of the advanced high-resolution displays to which they were connected. For applications that required simple line graphics but for which the expense of a framebuffer could not be justified, but there were many computer applications for which all that was required was the ability to render ordinary text in a quick and cost-effective fashion to a cathode ray tube. Text mode avoids the problem of memory by having dedicated display hardware re-render each line of text from characters into pixels with each scan of the screen by the cathode ray. In turn, the hardware needs only enough memory to store the pixels equivalent to one line of text at a time. For example, a screen buffer sufficient to hold a standard grid of 80 by 25 characters requires at least 2,000 bytes. S. dollars, another advantage of text mode is that it has relatively low bandwidth requirements in remote terminal use. Text mode rendering with user-defined characters has also been useful for 2D computer, a video controller implementing a text mode usually uses two distinct areas of memory. Character memory or a table contains a raster font in use. Display matrix tracks which character is in each cell, in the simple case the display matrix can be just a matrix of code points, but it usually stores for each character position not only a code, but also attributes. The video controller has two registers, scan line counter and dot counter, serving as coordinates in the dot matrix. Each of them must be divided by corresponding glyph size to obtain an index in the display matrix, the character memory resides in a read-only memory in some systems. Other systems allow the use of RAM for this purpose, making it possible to redefine the typeface, in some historical graphics chips, including the TMS9918, the MOS Technology VIC, and the Game Boy graphics hardware, this was actually the canonical way of doing pixel graphics
9.
Computer mouse
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A computer mouse is a pointing device that detects two-dimensional motion relative to a surface. This motion is typically translated into the motion of a pointer on a display, physically, a mouse consists of an object held in ones hand, with one or more buttons. Mice often also other elements, such as touch surfaces and wheels. The earliest known publication of the mouse as referring to a computer pointing device is in Bill Englishs July 1965 publication. The plural for the rodent is always mice in modern usage. The plural of a mouse is mouses and mice according to most dictionaries. The first recorded usage is mice, the online Oxford Dictionaries cites a 1984 use. The trackball, a pointing device, was invented in 1944 by Ralph Benjamin as part of a World War II-era fire-control radar plotting system called Comprehensive Display System. Benjamin was then working for the British Royal Navy Scientific Service, Benjamins project used analog computers to calculate the future position of target aircraft based on several initial input points provided by a user with a joystick. Benjamin felt that a more elegant input device was needed and invented what they called a ball for this purpose. The device was patented in 1947, but only a prototype using a ball rolling on two rubber-coated wheels was ever built, and the device was kept as a military secret. Another early trackball was built by British electrical engineer Kenyon Taylor in collaboration with Tom Cranston, Taylor was part of the original Ferranti Canada, working on the Royal Canadian Navys DATAR system in 1952. DATAR was similar in concept to Benjamins display, the trackball used four disks to pick up motion, two each for the X and Y directions. When the ball was rolled, the pickup discs spun and contacts on their outer rim made periodic contact with wires, by counting the pulses, the physical movement of the ball could be determined. A digital computer calculated the tracks and sent the data to other ships in a task force using pulse-code modulation radio signals. This trackball used a standard Canadian five-pin bowling ball and it was not patented, since it was a secret military project. Douglas Engelbart of the Stanford Research Institute has been credited in published books by Thierry Bardini, Paul Ceruzzi, Howard Rheingold, Engelbart was also recognized as such in various obituary titles after his death in July 2013. That November, while attending a conference on computer graphics in Reno, Nevada, Engelbart began to ponder how to adapt the underlying principles of the planimeter to X-Y coordinate input
10.
Console application
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A user typically interacts with a console application using only a keyboard and display screen, as opposed to GUI applications, which normally require the use of a mouse or other pointing device. Many console applications such as command line interpreters are command line tools, as the speed and ease-of-use of GUIs applications have improved over time, the use of console applications has greatly diminished, but not disappeared. Some users simply prefer console based applications, while some still rely on existing console applications to handle key data processing tasks. For data processing tasks and computer administration, these programming environments represent the level of operating system or data processing control after scripting. Console-based applications include Alpine, cmus, Irssi, Lynx, Midnight Commander, Music on Console, Mutt, nano, ne, newsbeuter, and ranger
11.
Video card
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A video card is an expansion card which generates a feed of output images to a display. Frequently, these are advertised as discrete or dedicated graphics cards, Standards such as MDA, CGA, HGC, Tandy, PGC, EGA, VGA, MCGA,8514 or XGA were introduced from 1982 to 1990 and supported by a variety of hardware manufacturers. The majority of video cards are built with either AMD-sourced or Nvidia-sourced graphics chips. Until 2000, 3dfx Interactive was also an important, and often groundbreaking, most video cards offer various functions such as accelerated rendering of 3D scenes and 2D graphics, MPEG-2/MPEG-4 decoding, TV output, or the ability to connect multiple monitors. Video cards also have sound capabilities to output sound – along with the video for connected TVs or monitors with integrated speakers. Graphics cards werent very useful for computers, since they didnt have the capability to run graphic-based games or high-resolution videos as modern computers do now. Within the industry, video cards are sometimes called graphics add-in-boards, abbreviated as AIBs, as an alternative to the use of a video card, video hardware can be integrated into the motherboard or the CPU. Both approaches can be called integrated graphics, motherboard-based implementations are sometimes called on-board video while CPU-based implementations are known as accelerated processing units. The ability to disable the integrated graphics sometimes also allows the use of a motherboard on which the on-board video has failed. Sometimes both the graphics and a dedicated graphics card can be used simultaneously to feed separate displays. The main advantages of integrated graphics include cost, compactness, simplicity, the performance disadvantage of integrated graphics arises because the graphics processor shares system resources with the CPU. A dedicated graphics card has its own random access memory, its own cooling system, upgrading to a dedicated graphics card offloads work from the CPU and system RAM, so not only will graphics processing be faster, but the computers overall performance may also improve. Both of the dominant CPU makers, AMD and Intel, are moving to APUs, as of late 2013, the best APUs provide graphics processing approaching mid-range mobile video cards and are adequate for casual gaming. Users seeking the highest video performance for gaming or other graphics-intensive uses should still choose computers with dedicated graphics cards. Beyond the enthusiast segment is the market for video cards for workstations used in the special effects industry. Nvidia is a player in the professional segment. As the processing power of cards has increased, so has their demand for electrical power. Current high-performance video cards tend to consume a great deal of power, for example, the thermal design power for the GeForce GTX TITAN is 250 Watts
12.
Personal computer
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A personal computer is a multi-purpose electronic computer whose size, capabilities, and price make it feasible for individual use. PCs are intended to be operated directly by a end-user, rather than by an expert or technician. In the 2010s, PCs are typically connected to the Internet, allowing access to the World Wide Web, personal computers may be connected to a local area network, either by a cable or a wireless connection. In the 2010s, a PC may be, a multi-component desktop computer, designed for use in a location a laptop computer, designed for easy portability or a tablet computer. In the 2010s, PCs run using a system, such as Microsoft Windows, Linux. The very earliest microcomputers, equipped with a front panel, required hand-loading of a program to load programs from external storage. Before long, automatic booting from permanent read-only memory became universal, in the 2010s, users have access to a wide range of commercial software, free software and free and open-source software, which are provided in ready-to-run or ready-to-compile form. Since the early 1990s, Microsoft operating systems and Intel hardware have dominated much of the computer market, first with MS-DOS. Alternatives to Microsofts Windows operating systems occupy a minority share of the industry and these include Apples OS X and free open-source Unix-like operating systems such as Linux and Berkeley Software Distribution. Advanced Micro Devices provides the alternative to Intels processors. PC is an initialism for personal computer, some PCs, including the OLPC XOs, are equipped with x86 or x64 processors but not designed to run Microsoft Windows. PC is used in contrast with Mac, an Apple Macintosh computer and this sense of the word is used in the Get a Mac advertisement campaign that ran between 2006 and 2009, as well as its rival, Im a PC campaign, that appeared in 2008. Since Apples transition to Intel processors starting 2005, all Macintosh computers are now PCs, the “brain” may one day come down to our level and help with our income-tax and book-keeping calculations. But this is speculation and there is no sign of it so far, in the history of computing there were many examples of computers designed to be used by one person, as opposed to terminals connected to mainframe computers. Using the narrow definition of operated by one person, the first personal computer was the ENIAC which became operational in 1946 and it did not meet further definitions of affordable or easy to use. An example of an early single-user computer was the LGP-30, created in 1956 by Stan Frankel and used for science and it came with a retail price of $47, 000—equivalent to about $414,000 today. Introduced at the 1965 New York Worlds Fair, the Programma 101 was a programmable calculator described in advertisements as a desktop computer. It was manufactured by the Italian company Olivetti and invented by the Italian engineer Pier Giorgio Perotto, the Soviet MIR series of computers was developed from 1965 to 1969 in a group headed by Victor Glushkov
13.
Operating system
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An operating system is system software that manages computer hardware and software resources and provides common services for computer programs. All computer programs, excluding firmware, require a system to function. Operating systems are found on many devices that contain a computer – from cellular phones, the dominant desktop operating system is Microsoft Windows with a market share of around 83. 3%. MacOS by Apple Inc. is in place, and the varieties of Linux is in third position. Linux distributions are dominant in the server and supercomputing sectors, other specialized classes of operating systems, such as embedded and real-time systems, exist for many applications. A single-tasking system can run one program at a time. Multi-tasking may be characterized in preemptive and co-operative types, in preemptive multitasking, the operating system slices the CPU time and dedicates a slot to each of the programs. Unix-like operating systems, e. g. Solaris, Linux, cooperative multitasking is achieved by relying on each process to provide time to the other processes in a defined manner. 16-bit versions of Microsoft Windows used cooperative multi-tasking, 32-bit versions of both Windows NT and Win9x, used preemptive multi-tasking. Single-user operating systems have no facilities to distinguish users, but may allow multiple programs to run in tandem, a distributed operating system manages a group of distinct computers and makes them appear to be a single computer. The development of networked computers that could be linked and communicate with each other gave rise to distributed computing, distributed computations are carried out on more than one machine. When computers in a work in cooperation, they form a distributed system. The technique is used both in virtualization and cloud computing management, and is common in large server warehouses, embedded operating systems are designed to be used in embedded computer systems. They are designed to operate on small machines like PDAs with less autonomy and they are able to operate with a limited number of resources. They are very compact and extremely efficient by design, Windows CE and Minix 3 are some examples of embedded operating systems. A real-time operating system is a system that guarantees to process events or data by a specific moment in time. A real-time operating system may be single- or multi-tasking, but when multitasking, early computers were built to perform a series of single tasks, like a calculator. Basic operating system features were developed in the 1950s, such as resident monitor functions that could run different programs in succession to speed up processing
14.
Emulator
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In computing, an emulator is hardware or software that enables one computer system to behave like another computer system. An emulator typically enables the host system to run software or use peripheral devices designed for the guest system, emulation refers to the ability of a computer program in an electronic device to emulate another program or device. Many printers, for example, are designed to emulate Hewlett-Packard LaserJet printers because so much software is written for HP printers. If a non-HP printer emulates an HP printer, any software written for a real HP printer will also run in the non-HP printer emulation and produce equivalent printing. Since at least the 1990s until today, some video game enthusiasts use emulators to play 1980s arcade games using the original 1980s programming code, a hardware emulator is an emulator which takes the form of a hardware device. In a theoretical sense, the Church-Turing thesis implies that any operating environment can be emulated within any other environment. However, in practice, it can be difficult, particularly when the exact behavior of the system to be emulated is not documented and has to be deduced through reverse engineering. Emulation is a strategy in digital preservation to combat obsolescence, emulation addresses the original hardware and software environment of the digital object, and recreates it on a current machine. The emulator allows the user to have access to any kind of application or operating system on a current platform and he further states that this should not only apply to out of date systems, but also be upwardly mobile to future unknown systems. Potentially better graphics quality than original hardware, potentially additional features original hardware didnt have. Emulators maintain the look, feel, and behavior of the digital object. Despite the original cost of developing an emulator, it may prove to be the more cost efficient solution over time, many emulators have already been developed and released under GNU General Public License through the open source environment, allowing for wide scale collaboration. Emulators allow software exclusive to one system to be used on another, for example, a PlayStation 2 exclusive video game could be played on a PC using an emulator. This is especially useful when the system is difficult to obtain. Copyright laws are not yet in effect to address saving the documentation and these protections make it more difficult to design emulators, since they must be accurate enough to avoid triggering the protections, whose effects may not be obvious. Emulators require better hardware than the system has. Because of its use of digital formats, new media art relies heavily on emulation as a preservation strategy. The paradox is that the emulation and the emulator have to be made to work on future computers, emulation techniques are commonly used during the design and development of new systems
15.
Xterm
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In computing, xterm is the standard terminal emulator for the X Window System. A user can have many different invocations of xterm running at once on the same display, xterm originated prior to the X Window System. It was originally written as a terminal emulator for the VAXStation 100 by Mark Vandevoorde, a student of Jim Gettys, in the summer of 1984. It rapidly became clear that it would be useful as part of X than as a standalone program. As Gettys tells the story, part of why xterms internals are so horrifying is that it was intended that a single process be able to drive multiple VS100 displays. After many years as part of the X reference implementation, around 1996 the main line of development then shifted to XFree86, many xterm variants are also available. Most terminal emulators for X started as variations on xterm and it emulates the VT220 and Tektronix 4010, and has experimental support for ReGIS. As with most X applications, xterm can be customized via global X resources files, per-user resource files, most of the command-line options correspond to resource settings, as noted in the manual page. While the name of the program is xterm, the X resource class is XTerm, the uxterm script overrides this, using the UXTerm resource class. Xterm normally does not have a menu bar, to access xterms three menus, users hold the control key and press the left, middle, or right mouse button. Support for a toolbar can be compiled-in, which invokes the same menus, xterm added a few protocols that have been adapted by other terminal emulators, such as xterm mouse tracking and the xterm 256 colors protocol.3 or later
16.
X Window System
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The X Window System is a windowing system for bitmap displays, common on UNIX-like computer operating systems. X provides the framework for a GUI environment, drawing and moving windows on the display device and interacting with a mouse. X does not mandate the user interface – this is handled by individual programs, as such, the visual styling of X-based environments varies greatly, different programs may present radically different interfaces. X originated at the Massachusetts Institute of Technology in 1984, the protocol has been version 11 since September 1987. The X. Org Foundation leads the X project, with the current reference implementation, X. Org Server, available as free and open source software under the MIT License, X is an architecture-independent system for remote graphical user interfaces and input device capabilities. Each person using a terminal has the ability to interact with the display with any type of user input device. X provides the framework, or primitives, for building such GUI environments, drawing and moving windows on the display and interacting with a mouse. X does not mandate the user interface, individual client programs handle this, programs may use Xs graphical abilities with no user interface. As such, the styling of X-based environments varies greatly. Unlike most earlier display protocols, X was specifically designed to be used over network connections rather than on an integral or attached display device. X features network transparency, which means an X program running on a computer somewhere on a network can display its user interface on an X server running on other computer on the network. The fact that the server is applied to the software in front of the user is often surprising to users accustomed to their programs being clients to services on remote computers. Xs network protocol is based on X command primitives and this approach allows both 2D and 3D operations by an X client application which might be running on a different computer to still be fully accelerated on the X servers display. X provides no support for audio, several projects exist to fill this niche. X uses a model, an X server communicates with various client programs. The server accepts requests for graphical output and sends back user input, a client and server can even communicate securely over the Internet by tunneling the connection over an encrypted network session. An X client itself may emulate an X server by providing services to other clients. This is known as X nesting, open-source clients such as Xnest and Xephyr support such X nesting
17.
Win32 console
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Win32 console is a text user interface implementation within the system of Windows API, which runs console applications. A Win32 console has a buffer and an input buffer. Win32 consoles are used for applications that do not need to display images. A Win32 console application may run in two modes, one mode places the text in a window and uses an operating systems font rendering. In this mode, an interaction with user is controlled by the windowing system. This is analogous to X Window System applications such as xterm, in a full screen mode Win32 console uses a hardware text mode and uploads a raster font to the video adapter. This is analogous to a system console. Full screen uses Windows built-in VGA driver, rather than any installed graphics drivers, therefore, it only supports VGA-compatible text modes, giving it a maximum character resolution of 80 columns by 28 rows. This contrasts with comparable consoles in various operating systems such as Linux. This mode was deprecated in Windows Vista as Windows Display Driver Model ceased to support these VGA modes and it was possible to circumvent this issue by installing a Windows XP display driver, however, Windows 8 and later only accepts WDDM drivers. An application can be switched between these two modes with Alt+Return key combination. Text environments in Unix-like systems usually do not have such a feature, the input buffer is a queue where events are stored. The output buffer is a grid where characters are stored. A console window may have several output buffers, only one of which is active for a given moment. The console window may be displayed as a window on the desktop, or may be switched to full screen to use the actual hardware text mode. The display mode is locked in background intensity mode, thus blinking does not work, also, the underscore attribute is not available. Programs may access a Win32 console either via high-level functions or via low-level functions, Win32 console programs are often mistaken for MS-DOS applications, especially on Windows 9x. However, a Win32 Console application is just a form of a native Win32 application
18.
Microsoft Windows
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Microsoft Windows is a metafamily of graphical operating systems developed, marketed, and sold by Microsoft. It consists of families of operating systems, each of which cater to a certain sector of the computing industry with the OS typically associated with IBM PC compatible architecture. Active Windows families include Windows NT, Windows Embedded and Windows Phone, defunct Windows families include Windows 9x, Windows 10 Mobile is an active product, unrelated to the defunct family Windows Mobile. Microsoft introduced an operating environment named Windows on November 20,1985, Microsoft Windows came to dominate the worlds personal computer market with over 90% market share, overtaking Mac OS, which had been introduced in 1984. Apple came to see Windows as an encroachment on their innovation in GUI development as implemented on products such as the Lisa. On PCs, Windows is still the most popular operating system, however, in 2014, Microsoft admitted losing the majority of the overall operating system market to Android, because of the massive growth in sales of Android smartphones. In 2014, the number of Windows devices sold was less than 25% that of Android devices sold and this comparison however may not be fully relevant, as the two operating systems traditionally target different platforms. As of September 2016, the most recent version of Windows for PCs, tablets, smartphones, the most recent versions for server computers is Windows Server 2016. A specialized version of Windows runs on the Xbox One game console, Microsoft, the developer of Windows, has registered several trademarks each of which denote a family of Windows operating systems that target a specific sector of the computing industry. It now consists of three operating system subfamilies that are released almost at the time and share the same kernel. Windows, The operating system for personal computers, tablets. The latest version is Windows 10, the main competitor of this family is macOS by Apple Inc. for personal computers and Android for mobile devices. Windows Server, The operating system for server computers, the latest version is Windows Server 2016. Unlike its clients sibling, it has adopted a strong naming scheme, the main competitor of this family is Linux. Windows PE, A lightweight version of its Windows sibling meant to operate as an operating system, used for installing Windows on bare-metal computers. The latest version is Windows PE10.0.10586.0, Windows Embedded, Initially, Microsoft developed Windows CE as a general-purpose operating system for every device that was too resource-limited to be called a full-fledged computer. The following Windows families are no longer being developed, Windows 9x, Microsoft now caters to the consumers market with Windows NT. Windows Mobile, The predecessor to Windows Phone, it was a mobile operating system
19.
Computer font
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A computer font is implemented as a digital data file containing a set of graphically related glyphs, characters, or symbols such as dingbats. A font family or typeface refers to the collection of related fonts across styles and sizes, there are three basic kinds of computer font file data formats, Bitmap fonts consist of a matrix of dots or pixels representing the image of each glyph in each face and size. Outline fonts use Bézier curves, drawing instructions and mathematical formulae to describe each glyph, which make the character outlines scalable to any size. Stroke fonts use a series of specified lines and additional information to define the profile, or size and shape of the line in a specific face, Bitmap fonts are faster and easier to use in computer code, but non-scalable, requiring a separate font for each size. Although all types are still in use, most fonts seen, fonts are designed and created using font editors. Fonts specifically designed for the screen and not printing are known as screen fonts. Fonts can be monospaced or proportional, however, the particular font-handling application can affect the spacing, particularly when doing justification. A bitmap font is one that each glyph as an array of pixels. It is less known as a raster font. Bitmap fonts are simply collections of images of glyphs. For each variant of the font, there is a set of glyph images. For example, if a font has three sizes, and any combination of bold and italic, then there must be 12 complete sets of images, advantages of bitmap fonts include, Extremely fast and simple to render Easier to create than other kinds. The limited processing power and memory of computer systems forced exclusive use of bitmap fonts. Bitmap fonts are used in the Linux console, the Windows recovery console, older dot matrix printers used bitmap fonts, often stored in the memory of the printer and addressed by the computers print driver. Bitmap fonts may be used in cross-stitch, to draw a string using a bitmap font, means to successively output bitmaps of each character that the string comprises, performing per-character indentation. Digital bitmap fonts may use monochrome or shades of gray, when displaying a text, typically an operating system properly represents the shades of gray as intermediate colors between the color of the font and that of the background. However, if the text is represented as an image with transparent background, Bitmap fonts look best at their native pixel size. Some systems using bitmap fonts can create some font variants algorithmically, for example, the original Apple Macintosh computer could produce bold by widening vertical strokes and oblique by shearing the image
20.
Computer terminal
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A computer terminal is an electronic or electromechanical hardware device that is used for entering data into, and displaying data from, a computer or a computing system. The function of a terminal is confined to display and input of data, a terminal that depends on the host computer for its processing power is called a dumb terminal or thin client. A personal computer can run terminal emulator software that replicates the function of a terminal, sometimes allowing concurrent use of local programs and access to a distant terminal host system. The terminal of the first working programmable, fully automatic digital Turing-complete computer, the Z3, had a keyboard, early user terminals connected to computers were electromechanical teleprinters/teletypewriters, such as the Teletype Model 33 ASR, originally used for telegraphy or the Friden Flexowriter. Later printing terminals such as the DECwriter LA30 were developed, however printing terminals were limited by the speed at which paper could be printed, and for interactive use the paper record was unnecessary. The problem was that the amount of memory needed to store the information on a page of text was comparable to the memory in low end minicomputers then in use. Displaying the information at video speeds was also a challenge and the control logic took up a rack worth of pre-integrated circuit electronics. Another approach involved the use of the tube, a specialized CRT developed by Tektronix that retained information written on it without the need to refresh. The Datapoint 3300 from Computer Terminal Corporation was announced in 1967 and shipped in 1969 and it solved the memory space issue mentioned above by using a digital shift-register design, and using only 72 columns rather than the later more common choice of 80. Some type of blinking cursor that can be positioned, the term intelligent in this context dates from 1969. Notable examples include the IBM2250 and IBM2260, predecessors to the IBM3270, providing even more processing possibilities, workstations like the Televideo TS-800 could run CP/M-86, blurring the distinction between terminal and Personal Computer. Most terminals were connected to minicomputers or mainframe computers and often had a green or amber screen, typically terminals communicate with the computer via a serial port via a null modem cable, often using an EIA RS-232 or RS-422 or RS-423 or a current loop serial interface. In fact, the design for the Intel 8008 was originally conceived at Computer Terminal Corporation as the processor for the Datapoint 2200. While early IBM PCs had single color green screens, these screens were not terminals. The screen of a PC did not contain any character generation hardware, all signals and video formatting were generated by the video display card in the PC, or by the CPU. An IBM PC monitor, whether it was the monochrome display or the 16-color display, was technically much more similar to an analog TV set than to a terminal. With suitable software a PC could, however, emulate a terminal, the Data General One could be booted into terminal emulator mode from its ROM. Since the advent and subsequent popularization of the computer, few genuine hardware terminals are used to interface with computers today
21.
Serial port
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In computing, a serial port is a serial communication interface through which information transfers in or out one bit at a time. Throughout most of the history of computers, data was transferred through serial ports to devices such as modems, terminals. Modern computers without serial ports may require serial-to-USB converters to allow compatibility with RS-232 serial devices, serial ports are still used in applications such as industrial automation systems, scientific instruments, point of sale systems and some industrial and consumer products. Server computers may use a port as a control console for diagnostics. Network equipment often use serial console for configuration, serial ports are still used in these areas as they are simple, cheap and their console functions are highly standardized and widespread. A serial port requires very little supporting software from the host system, some computers, such as the IBM PC, use an integrated circuit called a UART. This IC converts characters to and from asynchronous serial form, implementing the timing and framing of data in hardware, very low-cost systems, such as some early home computers, would instead use the CPU to send the data through an output pin, using the bit-banging technique. Early home computers often had proprietary serial ports with pinouts and voltage levels incompatible with RS-232, low-cost processors now allow higher-speed, but more complex, serial communication standards such as USB and FireWire to replace RS-232. These make it possible to connect devices that would not have operated feasibly over slower serial connections, such as storage, sound. Many personal computer motherboards still have at least one serial port, small-form-factor systems and laptops may omit RS-232 connector ports to conserve space, but the electronics are still there. RS-232 has been standard for so long that the circuits needed to control a serial port became very cheap and often exist on a single chip, sometimes also with circuitry for a parallel port. The individual signals on a serial port are unidirectional and when connecting two devices the outputs of one device must be connected to the inputs of the other, devices are divided into two categories data terminal equipment and data circuit-terminating equipment. A line that is an output on a DTE device is an input on a DCE device and vice versa so a DCE device can be connected to a DTE device with a straight wired cable, conventionally, computers and terminals are DTE while modems and peripherals are DCE. If it is necessary to connect two DTE devices a cross-over null modem, in the form of either an adapter or a cable, generally, serial port connectors are gendered, only allowing connectors to mate with a connector of the opposite gender. With D-subminiature connectors, the male connectors have protruding pins, either type of connector can be mounted on equipment or a panel, or terminate a cable. Connectors mounted on DTE are likely to be male, and those mounted on DCE are likely to be female, however, this is far from universal, for instance, most serial printers have a female DB25 connector, but they are DTEs. The desire to supply serial interface cards with two ports required that IBM reduce the size of the connector to fit onto a single card back panel, a DE-9 connector also fits onto a card with a second DB-25 connector. Starting around the time of the introduction of the IBM PC-AT, serial ports were built with a 9-pin connector to save cost
22.
Secure Shell
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Secure Shell is a cryptographic network protocol for operating network services securely over an unsecured network. The best known application is for remote login to computer systems by users. SSH provides a channel over an unsecured network in a client-server architecture. Common applications include remote command-line login and remote command execution, the protocol specification distinguishes between two major versions, referred to as SSH-1 and SSH-2. The most visible application of the protocol is for access to accounts on Unix-like operating systems. In 2015, Microsoft announced that they would include support for SSH in a future release. SSH was designed as a replacement for Telnet and for unsecured remote shell protocols such as the Berkeley rlogin, rsh and those protocols send information, notably passwords, in plaintext, rendering them susceptible to interception and disclosure using packet analysis. SSH uses public-key cryptography to authenticate the remote computer and allow it to authenticate the user, there are several ways to use SSH, one is to use automatically generated public-private key pairs to simply encrypt a network connection, and then use password authentication to log on. Another is to use a manually generated public-private key pair to perform the authentication, in this scenario, anyone can produce a matching pair of different keys. The public key is placed on all computers that must allow access to the owner of the private key. While authentication is based on the key, the key itself is never transferred through the network during authentication. SSH only verifies whether the person offering the public key also owns the matching private key. In all versions of SSH it is important to verify unknown public keys, i. e. associate the public keys with identities, accepting an attackers public key without validation will authorize an unauthorized attacker as a valid user. On Unix-like systems, the list of authorized public keys is typically stored in the directory of the user that is allowed to log in remotely. This file is respected by SSH only if it is not writable by anything apart from the owner, when the public key is present on the remote end and the matching private key is present on the local end, typing in the password is no longer required. However, for security the private key itself can be locked with a passphrase. The private key can also be looked for in standard places, the ssh-keygen utility produces the public and private keys, always in pairs. SSH also supports password-based authentication that is encrypted by automatically generated keys, in this case the attacker could imitate the legitimate server side, ask for the password, and obtain it
23.
Linux kernel
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The Linux kernel is a monolithic Unix-like computer operating system kernel. The Android operating system for computers, smartphones and smartwatches is also based atop the Linux kernel. While the adoption on desktop computers is low, Linux-based operating systems dominate nearly every segment of computing. As of November 2016, all but two of the worlds 500 most powerful supercomputers run Linux, Linux rapidly attracted developers and users who adopted it as the kernel for other free software projects, notably the GNU Operating System. The Linux kernel has received contributions from nearly 12,000 programmers from more than 1,200 companies, the Linux kernel API, the application programming interface through which user programs interact with the kernel, is meant to be very stable and to not break userspace programs. As part of the functionality, device drivers control the hardware. However, the interface between the kernel and loadable kernel modules, unlike in many other kernels and operating systems, is not meant to be stable by design. The Linux kernel, developed by contributors worldwide, is a prominent example of free, day-to-day development discussions take place on the Linux kernel mailing list. The Linux kernel is released under the GNU General Public License version 2, in April 1991, Linus Torvalds, at the time a 21-year-old computer science student at the University of Helsinki, Finland, started working on some simple ideas for an operating system. He started with a task switcher in Intel 80386 assembly language, on 25 August 1991, Torvalds posted the following to comp. os. minix, a newsgroup on Usenet, Im doing a operating system for 386 AT clones. This has been brewing since April, and is starting to get ready, id like any feedback on things people like/dislike in minix, as my OS resembles it somewhat. Ive currently ported bash and gcc, and things seem to work and this implies that Ill get something practical within a few months Yes - its free of any minix code, and it has a multi-threaded fs. It is NOT portable, and it never will support anything other than AT-harddisks, as thats all I have. Its mostly in C, but most people wouldnt call what I write C and it uses every conceivable feature of the 386 I could find, as it was also a project to teach me about the 386. As already mentioned, it uses a MMU, for both paging and segmentation and its the segmentation that makes it REALLY386 dependent. Some of my C-files are almost as much assembler as C, unlike minix, I also happen to LIKE interrupts, so interrupts are handled without trying to hide the reason behind them. After that, many people contributed code to the project, early on, the MINIX community contributed code and ideas to the Linux kernel. At the time, the GNU Project had created many of the components required for an operating system
24.
Unix-like
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A Unix-like operating system is one that behaves in a manner similar to a Unix system, while not necessarily conforming to or being certified to any version of the Single UNIX Specification. A Unix-like application is one that behaves like the corresponding Unix command or shell, there is no standard for defining the term, and some difference of opinion is possible as to the degree to which a given operating system or application is Unix-like. The Open Group owns the UNIX trademark and administers the Single UNIX Specification and they do not approve of the construction Unix-like, and consider it a misuse of their trademark. Other parties frequently treat Unix as a genericized trademark, in 2007, Wayne R. Gray sued to dispute the status of UNIX as a trademark, but lost his case, and lost again on appeal, with the court upholding the trademark and its ownership. Unix-like systems started to appear in the late 1970s and early 1980s, many proprietary versions, such as Idris, UNOS, Coherent, and UniFlex, aimed to provide businesses with the functionality available to academic users of UNIX. These largely displaced the proprietary clones, growing incompatibility among these systems led to the creation of interoperability standards, including POSIX and the Single UNIX Specification. Various free, low-cost, and unrestricted substitutes for UNIX emerged in the 1980s and 1990s, including 4. 4BSD, Linux, some of these have in turn been the basis for commercial Unix-like systems, such as BSD/OS and OS X. The various BSD variants are notable in that they are in fact descendants of UNIX, however, the BSD code base has evolved since then, replacing all of the AT&T code. Since the BSD variants are not certified as compliant with the Single UNIX Specification, dennis Ritchie, one of the original creators of Unix, expressed his opinion that Unix-like systems such as Linux are de facto Unix systems. Eric S. Raymond and Rob Landley have suggested there are three kinds of Unix-like systems, Genetic UNIX Those systems with a historical connection to the AT&T codebase. Most commercial UNIX systems fall into this category, so do the BSD systems, which are descendants of work done at the University of California, Berkeley in the late 1970s and early 1980s. Some of these systems have no original AT&T code but can trace their ancestry to AT&T designs. Trademark or branded UNIX These systems—largely commercial in nature—have been determined by the Open Group to meet the Single UNIX Specification and are allowed to carry the UNIX name, many ancient UNIX systems no longer meet this definition. Around 2001, Linux was given the opportunity to get a certification including free help from the POSIX chair Andrew Josey for the price of one dollar. Some non-Unix-like operating systems provide a Unix-like compatibility layer, with degrees of Unix-like functionality. IBM z/OSs UNIX System Services is sufficiently complete to be certified as trademark UNIX, cygwin and MSYS both provide a GNU environment on top of the Microsoft Windows user API, sufficient for most common open source software to be compiled and run. Subsystem for Unix-based Applications provides Unix-like functionality as a Windows NT subsystem, Windows Subsystem for Linux provides a Linux-compatible kernel interface developed by Microsoft and containing no Linux code, with Ubuntu user-mode binaries running on top of it
25.
Fault tolerance
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Fault tolerance is the property that enables a system to continue operating properly in the event of the failure of some of its components. Fault tolerance is particularly sought after in high-availability or life-critical systems, the ability of maintaining functionality when portions of a system break down is referred to as graceful degradation. A fault-tolerant design enables a system to continue its operation, possibly at a reduced level, rather than failing completely. That is, the system as a whole is not stopped due to either in the hardware or the software. However, if the consequences of a system failure are catastrophic, or the cost of making it sufficiently reliable is very high, a better solution may be to use some form of duplication. In any case, if the consequence of a failure is so catastrophic. This is similar to recovery but can be a human action if humans are present in the loop. A highly fault-tolerant system might continue at the level of performance even though one or more components have failed. For example, a building with a electrical generator will provide the same voltage to wall outlets even if the grid power fails. In computers, a program might fail-safe by executing a graceful exit in order to prevent data corruption after experiencing an error, a similar distinction is made between failing well and failing badly. Fail-deadly is the strategy, which can be used in weapon systems that are designed to kill or injure targets even if part of the system is damaged or destroyed. A system that is designed to experience graceful degradation, or to fail soft operates at a level of performance after some component failures. In fault-tolerant computer systems, programs that are considered robust are designed to continue operation despite an error, exception, or invalid input, software brittleness is the opposite of robustness. Likewise, a fail-fast component is designed to report at the first point of failure, rather than allow downstream components to fail and this allows easier diagnosis of the underlying problem, and may prevent improper operation in a broken state. If each component, in turn, can continue to function when one of its subcomponents fails, this will allow the total system to continue to operate as well. Using a passenger vehicle as an example, a car can have run-flat tires, the punctured run-flat tire may be used for a limited time at a reduced speed. Redundancy is the provision of functional capabilities that would be unnecessary in a fault-free environment and this can consist of backup components that automatically kick in should one component fail. For example, large trucks can lose a tire without any major consequences
26.
Standard streams
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In computer programming, standard streams are preconnected input and output communication channels between a computer program and its environment when it begins execution. The three I/O connections are called standard input, standard output and standard error, originally I/O happened via a physically connected system console, but standard streams abstract this. When a command is executed via a shell, the streams are typically connected to the text terminal on which the shell is running. More generally, a process will inherit the standard streams of its parent process. Users generally know standard streams as input and output channels that handle data coming from an input device, the data may be text with any encoding, or binary data. Streams may be used to chain applications, meaning the output of a program is used for input to another application, in many operating systems this is expressed by listing the application names, separated by the vertical bar character, for this reason often called the pipeline character. A well-known example is the use of an application, such as more. In most operating systems predating Unix, programs had to connect to the appropriate input and output devices. OS-specific intricacies caused this to be a programming task. One of Unixs several groundbreaking advances was abstract devices, which removed the need for a program to know or care what kind of devices it was communicating with, older operating systems forced upon the programmer a record structure and frequently non-orthogonal data semantics and device control. Unix eliminated this complexity with the concept of a data stream, a program may also write bytes as desired and need not declare how many there will be, or how they will be grouped. Another Unix breakthrough was to automatically associate input and output by default — the program did nothing to establish input and output for a typical input-process-output program. In contrast, previous operating systems usually required some—often complex—job control language to establish connections, since Unix provided standard streams, the Unix C runtime environment was obliged to support it as well. As a result, most C runtime environments, regardless of the operating system, standard input is stream data going into a program. The program requests data transfers by use of the read operation, not all programs require stream input. For example, the dir and ls programs may take command-line arguments, unless redirected, standard input is expected from the keyboard which started the program. The file descriptor for standard input is 0, the POSIX <unistd. h> definition is STDIN_FILENO, the corresponding <stdio. h> variable is FILE* stdin, similarly, standard output is the stream where a program writes its output data. The program requests data transfer with the write operation, for example, the file rename command is silent on success
27.
American National Standards Institute
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The organization also coordinates U. S. standards with international standards so that American products can be used worldwide. ANSI accredits standards that are developed by representatives of other organizations, government agencies, consumer groups, companies. These standards ensure that the characteristics and performance of products are consistent, that use the same definitions and terms. ANSI also accredits organizations that carry out product or personnel certification in accordance with requirements defined in international standards, the organizations headquarters are in Washington, DC. ANSIs operations office is located in New York City, the ANSI annual operating budget is funded by the sale of publications, membership dues and fees, accreditation services, fee-based programs, and international standards programs. ANSI was originally formed in 1918, when five engineering societies, in 1928, the AESC became the American Standards Association. In 1966, the ASA was reorganized and became United States of America Standards Institute, the present name was adopted in 1969. At the behest of the AIEE, they invited the U. S. government Departments of War, Navy, according to Adam Stanton, the first permanent secretary and head of staff in 1919, AESC started as an ambitious program and little else. Staff for the first year consisted of one executive, Clifford B, lePage, who was on loan from a founding member, ASME. An annual budget of $7,500 was provided by the founding bodies, aNSIs members are government agencies, organizations, corporations, academic and international bodies, and individuals. In total, the Institute represents the interests of more than 125,000 companies and 3.5 million professionals, though ANSI itself does not develop standards, the Institute oversees the development and use of standards by accrediting the procedures of standards developing organizations. ANSI accreditation signifies that the used by standards developing organizations meet the Institutes requirements for openness, balance, consensus. Voluntary consensus standards quicken the market acceptance of products while making clear how to improve the safety of products for the protection of consumers. There are approximately 9,500 American National Standards that carry the ANSI designation, the Institute is the official U. S. S. ANSI participates in almost the entire program of both the ISO and the IEC, and administers many key committees and subgroups. In many instances, U. S. standards are taken forward to ISO and IEC, through ANSI or the USNC, in 2009, ANSI and the National Institute of Standards and Technology formed the Nuclear Energy Standards Coordination Collaborative. NESCC is a joint initiative to identify and respond to the current need for standards in the nuclear industry. The ASA photographic exposure system, originally defined in ASA Z38.2.1 and ASA PH2.5, together with the DIN system, became the basis for the ISO system, a standard for the set of values used to represent characters in digital computers
28.
Cursor (user interface)
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The mouse cursor is also called a pointer, owing to its resemblance in usage to a pointing stick. A cursor is the given to the transparent slide engraved with a hairline that is used for marking a point on a slide rule. The term was transferred to computers through analogy. In text mode displays, it was not possible to show a bar between characters to show where the new text would be inserted, so an underscore or block cursor was used instead. In situations where a block was used, the block was created by inverting the pixels of the character using the boolean math exclusive or function. On text editors and word processors of modern design on bitmapped displays, in a typical text editing application, the cursor can be moved by pressing various keys. These include the four keys, the Page Up and Page Down keys, the Home key, the End key. The position of the cursor also may be changed by moving the pointer to a different location in the document. The blinking of the cursor is usually temporarily suspended when it is being moved, otherwise. In this way, a block cursor may be seen as a piece of selected text one character wide, in some cases, the cursor may split into two parts, each indicating where left-to-right and right-to-left text would be inserted. The I-beam pointer is a cursor shaped like the capital letter I, the purpose of this cursor to indicate text can be highlighted, inserted, or changed. The pointer or mouse cursor echoes movements of the device, commonly a mouse. This kind of cursor is used to manipulate elements of user interfaces such as menus, buttons. It may be called a pointer, because the mouse is the dominant type of pointing device used with desktop computers. The idea of a cursor being used as a marker or insertion point for new data or transformations, such as rotation, blender, for instance, uses a 3D cursor to determine where future operations are to take place. A real-life cursor such as this was featured as a character in the science fiction TV series Automan. Susan Kare, designer of several of the common cursor shapes Creating and controlling browser cursors Cross-browser CSS custom cursors Installing A Cursor On Your Computer
29.
FreeDOS
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FreeDOS is a free operating system for IBM PC compatible computers. It intends to provide a complete DOS-compatible environment for running legacy software, FreeDOS can be booted from a floppy disk or USB flash drive. It is designed to run well under virtualization or x86 emulation, unlike MS-DOS, FreeDOS is composed of Free Software and open-source software, licensed under the terms of the GNU General Public License. Therefore, its distribution does not require license fees or royalties. However, other packages which form part of the FreeDOS project include non-GPL software considered worth preserving, such as 4DOS, the FreeDOS project began 29 June 1994, after Microsoft announced it would no longer sell or support MS-DOS. Jim Hall who at the time was a student posted a manifesto proposing the development of an open-source replacement, within a few weeks, other programmers including Pat Villani and Tim Norman joined the project. Between them, a kernel, the COMMAND. COM command line interpreter, there have been many official pre-release distributions of FreeDOS before the final FreeDOS1.0 distribution. GNU/DOS, a distribution of FreeDOS, was discontinued after version 1.0 was released. The legacy version 1.0 consisted of two CDs, one of which was an 8MB install CD targeted at regular users and the other which was a larger 49MB live CD that also held the source code of the project. FreeDOS is used by companies, Dell preloads FreeDOS with their n-series desktops to reduce their cost. The firm has been criticized for making these machines no cheaper, HP provides FreeDOS as an option in its dc5750 desktops, Mini 5101 netbooks and Probook laptops. FreeDOS is also used as media for updating the BIOS firmware in HP systems. GRCs SpinRite 6, a hard drive maintenance and recovery program, intels Solid-State Drive Firmware Update Tool loads the FreeDOS kernel. FreeDOS is also used in independent projects, FUZOMA is a FreeDOS-based distribution that can boot from a floppy disk. FED-UP is the Floppy Enhanced DivX Universal Player, FreeDOS itself requires a PC/XT machine with at least 640kB of memory. Programs not bundled with FreeDOS often require additional system resources, FreeDOS is mostly compatible with MS-DOS. It supports COM executables, standard DOS executables and Borlands 16-bit DPMI executables and it is also possible to run 32-bit DPMI executables using DOS extenders. Furthermore, with use of HX DOS Extender, many Win32 console applications function properly in FreeDOS, as do some rare GUI programs, like QEMU, FreeDOS is able to run Microsoft Windows 1.0 and 2.0 releases
30.
IBM Personal Computer
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The IBM Personal Computer, commonly known as the IBM PC, is the original version and progenitor of the IBM PC compatible hardware platform. It is IBM model number 5150, and was introduced on August 12,1981 and it was created by a team of engineers and designers under the direction of Don Estridge of the IBM Entry Systems Division in Boca Raton, Florida. IBM compatible became an important criterion for sales growth, only the Apple Macintosh family kept significant market share without compatibility with the IBM personal computer, International Business Machines, one of the worlds largest companies, had a 62% share of the mainframe computer market in 1981. Its share of the computer market, however, had declined from 60% in 1970 to 32% in 1980. In 1979 BusinessWeek asked, Is IBM just another stodgy, mature company, by 1981 its stock price had declined by 22%. IBMs earnings for the first half the year grew by 5. 3%—one third of the inflation rate—while those of minicomputer maker Digital Equipment Corporation grew by more than 35%. B. M, No longer dominates the computer business. IBM wished to avoid the outcome with the new personal computer industry, dominated by the Commodore PET, Atari 8-bit family, Apple II, Tandy Corporations TRS-80. With $150 million in sales by 1979 and projected growth of more than 40% in the early 1980s. The Japanese project, codenamed Go, ended before the 1981 release of the American-designed IBM PC codenamed Chess, whether IBM had waited too long to enter an industry in which Apple and others were already successful was unclear. An observer stated that IBM bringing out a computer would be like teaching an elephant to tap dance. Successful microcomputer company Vector Graphics fiscal 1980 revenue was $12 million, the company only sold through its internal sales force, had no experience with resellers or retail stores, and did not introduce the first product designed to work with non-IBM equipment until 1980. Another observer claimed that IBM made decisions so slowly that, when tested, as with other large computer companies, its new products typically required about four to five years for development. IBM had to learn how to develop, mass-produce. The potential importance to microcomputers of a company so prestigious, that a saying in American companies stated No one ever got fired for buying IBM, was nonetheless clear. InfoWorld, which described itself as The Newsweekly for Microcomputer Users, stated that for my grandmother, is far and away the media star, not because of its features, but because it exists at all. When the number eight company in the Fortune 500 enters the field, the influence of a personal computer made by a company whose name has literally come to mean computer to most of the world is hard to contemplate. The editorial acknowledged that some factions in our industry have looked upon IBM as the enemy, desktop sized programmable calculators by Hewlett Packard had evolved into the HP9830 BASIC language computer by 1972. In 1972–1973 a team led by Dr. SCAMP emulated an IBM1130 minicomputer to run APL\1130, in 1973 APL was generally available only on mainframe computers, and most desktop sized microcomputers such as the Wang 2200 or HP9800 offered only BASIC
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IBM PC compatible
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IBM PC compatible computers are those similar to the original IBM PC, XT, and AT, able to run the same software and support the same expansion cards as those. Such computers used to be referred to as PC clones, or IBM clones, Columbia Data Products built the first clone of the IBM personal computer by a clean room implementation of its BIOS. Early IBM PC compatibles used the computer bus as the original PC. The IBM AT compatible bus was named the Industry Standard Architecture bus by manufacturers of compatible computers. The term IBM PC compatible is now a historical description only, only the Apple Macintosh classic Mac OS and macOS kept significant market share without compatibility with the IBM personal computer, so consumers are typically identified as being a PC or Mac user. IBM decided in 1980 to market a low-cost single-user computer as quickly as possible in response to Apple Computers success in the microcomputer market. On 12 August 1981, the first IBM PC went on sale, there were three operating systems available for it. The least expensive and most popular was PC DOS made by Microsoft, in a crucial concession, IBMs agreement allowed Microsoft to sell its own version, MS-DOS, for non-IBM computers. The only component of the original PC architecture exclusive to IBM was the BIOS and this software would run on any machine using MS-DOS or PC-DOS. Software that directly addressed the hardware instead of making standard calls was faster, however, software addressing IBM PC hardware in this way would not run on MS-DOS machines with different hardware. The 808x computer marketplace rapidly excluded all machines which were not hardware-, the 640 KB barrier on conventional system memory available to MS-DOS is a legacy of that period, other non-clone machines, while subject to a limit, could exceed 640 kB. Rumors of lookalike, compatible computers, created without IBMs approval, by June 1983 PC Magazine defined PC clone as a computer accommodate the user who takes a disk home from an IBM PC, walks across the room, and plugs it into the foreign machine. Because of a shortage of IBM PCs that year, many customers purchased clones instead, Columbia Data Products produced the first computer more or less compatible to the IBM PC standard during June 1982, soon followed by Eagle Computer. Compaq announced its first IBM PC compatible in November 1982, the Compaq Portable, the Compaq was the first sewing machine-sized portable computer that was essentially 100% PC-compatible. The company could not copy the BIOS directly as a result of the decision in Apple v. Franklin. Each computer would have its own Original Equipment Manufacturer version of MS-DOS, any software written for MS-DOS would operate on any MS-DOS computer, despite variations in hardware design. This expectation seemed reasonable in the marketplace of the time. Until then Microsoft was based primarily on computer languages such as BASIC, the established small system operating software was CP/M from Digital Research which was in use both at the hobbyist level and by the more professional of those using microcomputers
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BIOS
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The BIOS is a type of firmware used to perform hardware initialization during the booting process on IBM PC compatible computers, and to provide runtime services for operating systems and programs. The BIOS firmware is built into personal computers, and it is the first software they run when powered on, the name itself originates from the Basic Input/Output System used in the CP/M operating system in 1975. Originally proprietary to the IBM PC, the BIOS has been engineered by companies looking to create compatible systems. The fundamental purposes of the BIOS in modern PCs are to initialize and test the hardware components. Variations in the hardware are hidden by the BIOS from programs that use BIOS services instead of directly accessing the hardware. MS-DOS, which was the dominant PC operating system from the early 1980s until the mid-1990s, relied on BIOS services for disk, keyboard, and text display functions. Most BIOS implementations are specifically designed to work with a computer or motherboard model. This allows easy updates to the BIOS firmware so new features can be added or bugs can be fixed, unified Extensible Firmware Interface was designed as a successor to BIOS, aiming to address its technical shortcomings. As of 2014, new PC hardware predominantly ships with UEFI firmware, together with the underlying hardware-specific, but operating system-independent System BIOS, which resides in ROM, it represents the analogous to the CP/M BIOS. With the introduction of PS/2 machines, IBM divided the System BIOS into real-mode, the BIOS of the original IBM PC XT had no interactive user interface. Options on the IBM PC and XT were set by switches and jumpers on the main board, starting around the mid-1990s, it became typical for the BIOS ROM to include a BIOS configuration utility or BIOS setup utility, accessed at system power-up by a particular key sequence. This program allowed the user to set configuration options, of the type formerly set using DIP switches. The disk was supplied with the computer, and if it was lost the settings could not be changed. Instead of battery-backed RAM, the modern Wintel machine may store the BIOS configuration settings in flash ROM, early Intel processors started at physical address 000FFFF0h. When a modern x86 microprocessor is reset, it starts in pseudo 16-bit real mode, the code segment register is initialized with selector F000h, base FFFF0000h, and limit FFFFh, so that execution starts at 4 GB minus 16 bytes. The platform logic maps this address into the system ROM, mirroring address 000FFFF0h, if the system has just been powered up or the reset button was pressed, the full power-on self-test is run. This saves the time used to detect and test all memory. If the download was apparently successful, the BIOS would verify a checksum on it and then run it
33.
DOS
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None of these systems were officially named DOS, and indeed DOS is a general term for disk operating system. MS-DOS dominated the IBM PC compatible market between 1981 and 1995, and Microsoft Windows, still ran on top of it until about 2001, dozens of other operating systems also use the acronym DOS, including DOS/360 from 1966. Others are Apple DOS, Apple ProDOS, Atari DOS, Commodore DOS, TRSDOS, see List of DOS operating systems § Other operating systems. IBM PC DOS and its predecessor, 86-DOS, resembled Digital Researchs CP/M—the dominant disk operating system for 8-bit Intel 8080, DOS instead ran on Intel 8086 16-bit processors. Starting with MS-DOS1.28 and PC DOS2.0 the operating system incorporated various features inspired by Xenix, when IBM introduced the IBM PC, built with the Intel 8088 microprocessor, they needed an operating system. Seeking an 8088-compatible build of CP/M, IBM initially approached Microsoft CEO Bill Gates, IBM was sent to Digital Research, and a meeting was set up. However, the negotiations for the use of CP/M broke down, Digital Research wished to sell CP/M on a royalty basis, while IBM sought a single license. Digital Research founder Gary Kildall refused, and IBM withdrew, Gates in turn approached Seattle Computer Products. There, programmer Tim Paterson had developed a variant of CP/M-80, the system was initially named QDOS, before being made commercially available as 86-DOS. Microsoft purchased 86-DOS, allegedly for $50,000 and this became Microsoft Disk Operating System, MS-DOS, introduced in 1981. Within a year Microsoft licensed MS-DOS to over 70 other companies, Microsoft later required the use of the MS-DOS name, with the exception of the IBM variant. IBM continued to develop their version, PC DOS, for the IBM PC, Digital Research became aware that an operating system similar to CP/M was being sold by IBM, and threatened legal action. IBM responded by offering an agreement, they would give PC consumers a choice of PC DOS or CP/M-86, side-by-side, CP/M cost almost $200 more than PC DOS, and sales were low. CP/M faded, with MS-DOS and PC DOS becoming the operating system for PCs. Microsoft originally sold MS-DOS only to original equipment manufacturers, one major reason for this was that not all early PCs were 100% IBM PC compatible. DOS was structured such that there was a separation between the specific device driver code and the DOS kernel. Microsoft provided an OEM Adaptation Kit which allowed OEMs to customize the device driver code to their particular system, by the early 1990s, most PCs adhered to IBM PC standards so Microsoft began selling MS-DOS in retail with MS-DOS5.0. In the mid-1980s Microsoft developed a version of DOS
34.
VGA-compatible text mode
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The implementation of computer monitor text mode on VGA-compatible hardware is quite complex. Its use on PC-compatible computers was widespread in 1980s–1990s, but persists today for some applications even on modern desktop computers, the main features of VGA text mode are colored characters and their background, blinking, various shapes of the cursor, and loadable fonts. The Linux console traditionally uses hardware VGA-compatible text modes, and the Win32 console environment has an ability to switch the screen to text mode for some text window sizes. Each screen character is represented by two bytes aligned as a 16-bit word accessible by the CPU in a single operation. This byte-pair scheme is among the features that the VGA inherited from the EGA, CGA, ^ Depending on the mode setup, attribute bit 7 may be either the blink bit or the fourth background color bit. ^ Attribute bit 3 also selects between fonts A and B, therefore, if these fonts are not the same, this bit is simultaneously an additional code point bit. ^ Attribute bit 0 also enables underline, if certain other attribute bits are set to zero, colors are assigned in the same way as in 4-bit indexed color graphic modes. However, since this is an MDA-compatible feature, the attribute bits not used by the MDA must be set to zero or the underline will not be shown and this means that only bits 3 and 7 can be set concurrently with bit 0. With the default VGA palette, setting bit 0 to enable underline will also change the colour to blue. This means text in two colors can be underlined. Despite all this, the underline is not normally visible in color modes, as the location of the underline defaults to a scanline below the character glyph, if the underline location is set to a visible scanline then the underline will appear. Screen fonts used in EGA and VGA are monospace raster fonts containing 256 glyphs, all glyphs in a font are the same size, but this size can be changed. Typically glyphs are 8 dots wide and 8-16 dots high, however the height can be any value up to a maximum of 32. Each row of a glyph is coded in an 8 bit byte, with high bits to the left of the glyph, along with several hardware-dependent fonts stored in the adapter’s ROM, the text mode offers 8 loadable fonts. Two active font pointers select two of the fonts, although they usually point to the same font. When they each point to different fonts, attribute bit 3 acts as a font selection bit instead of as a foreground color bit and this error can be overcome by changing the palette registers to contain two copies of an 8-color palette. There are modes with a box width of 9-dots, however the 9th column is used for spacing between characters, so the content cannot be changed. It is always blank, and drawn with the current background colour, an exception to this is in Line Graphics Enable mode, which causes code points 0xC0 to 0xDF inclusive to have the 8th column repeated as the 9th
35.
Impulse Tracker
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Impulse Tracker is a multi-track digital sound tracker. Originally released in 1995 by Jeffrey Lim as Freeware with commercial extensions, in 2014, Impulse Tracker became open-source software when on the 20 year anniversary the source code was released. Impulse Tracker was authored by Jeffrey Pulse Lim for the MS-DOS/x86-PC platform, Impulse Tracker was coded in Assembly language, and the interface was heavily influenced by that of Scream Tracker 3. The first released version is from year 1995 and included example music was provided by Jeffrey Lim, the software was distributed as freeware, though for a fee the author supplies extra features, such as support for WAV output and co-editing songs over IPX networks. After the stereo WAV writer plugin was publicly pirated, the author announced that he would discontinue development after version 2.14. The latest version was v2.14 Patch #5 released on April 8,1999, on February 16,2014, Jeffrey Lim announced that he would release the complete source code of Impulse Tracker as part of its 20-year anniversary. On October 19,2014, the first part of the code was released on a Bitbucket repository. On December 25,2014, the parts were added. Like in most module editors, music is arranged on a grid of channels, each supports note on and note off instructions similar to MIDI. Impulse Tracker modules use the. IT file extension, new Note Actions is a feature that handles commands received on the same channel as another instrument which is still playing. NNAs allow the user to customize the subsequent action, Cut, continue, The old instrument continues to play using its ADSR curve. Off, The old instrument begins the section of its ADSR curve. Fade, The old instrument fades out to 0 volume at a designated rate overriding the ADSR curve, Impulse Tracker supports hardware MIDI channels on the Gravis Ultrasound, InterWave and Sound Blaster 32 card families. The. IT file format is the native to Impulse Tracker. Some player software supports the. ITZ format, which is a zip file that contains a. IT file. Open Modplug Tracker supports the IT format and has its own format MPTM which is the IT format with added capability, erez Eizen of Infected Mushroom and Shiva Shidapu composed his first trance music on Impulse Tracker. Ian Stocker used IT with other software in his collaboration for the music in the Nintendo DS version of The Sims 2, the video games Pocket Tanks and Grid Wars use the IT format for some of their songs. Various games by Epic Games such as the first Unreal and Unreal Tournament as well as Deus Ex used the IT format in an UMX container format, the video game composer and demoscener Andrew Sega used Impulse Tracker extensively in his demoscene days
36.
Box-drawing character
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Box-drawing characters, also known as line-drawing characters, are a form of semigraphics widely used in text user interfaces to draw various geometric frames and boxes. In graphical user interfaces, these characters are less useful as it is much simpler to draw lines and rectangles directly with graphical APIs. Box-drawing characters work only with monospaced fonts, however, they are useful for plaintext comments on websites. Used along with box-drawing characters are block elements, shade characters and these can be used for filling regions of the screen and portraying drop shadows. In many Unicode fonts only the subset that is available in the IBM PC character set will exist. The hardware code page of the original IBM PC supplied the following box-drawing characters, on many Unix systems and early dial-up bulletin board systems the only common standard for box-drawing characters was the VT100 alternate character set. Modern Unix terminal emulators use Unicode and thus have access to the characters listed above. Many microcomputers of the 1970s and 1980s had their own character sets. Some of these sets, such as Commodores PETSCII, include box-drawing symbols with no corresponding Unicode character, the Sinclair ZX81 and Spectrum included a set of text semigraphics with block elements and dithering patterns. The BBC Micro could utilise the Teletext 7-bit character set, which had 128 box-drawing characters, whose code points were shared with the regular alphanumeric, control characters were used to switch between regular text and box drawing. MouseText is a set of characters for the Apple IIc, IIe. Some recent embedded systems use proprietary character sets, usually extensions to ISO8859 character sets. The World Standard Teletext uses pixel-drawing characters for some graphics, a character cell is divided in 2×3 regions, and 26 =64 code positions are allocated for all possible combinations of pixels. However, these characters are not included in the Unicode standard
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Code page 437
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Code page 437 is the character set of the original IBM PC, or DOS. It is also known as CP437, OEM-US, OEM437, PC-8, the set includes ASCII codes 32–126, extended codes for accented letters, some Greek letters, icons, and line-drawing symbols. It is sometimes referred to as the OEM font or high ASCII and this character set remains the primary font in the core of any EGA and VGA-compatible graphics card. Text shown when a PC reboots, before any other font can be loaded from a storage medium, many file formats developed at the time of the IBM PC are based on code page 437 as well. The IBM Enhanced Graphics Adapter contained an 8×14 pixels-per-character version, all these display adapters have text modes in which each character cell contains an 8-bit character code point, giving 256 possible values for graphic characters. All 256 codes were assigned a character in ROM, including the codes from 0 to 31 that were reserved in ASCII for non-graphical control characters. Various Eastern European PCs used different character sets, sometimes user-selectable via jumpers or CMOS setup. These sets were designed to match 437 as much as possible, for sharing the code points for many of the line-drawing characters. A legacy of code page 437 and other DOS codepages is the set of number combinations used in Windows Alt keycodes introduced in the first versions of DOS, the user could enter a character by holding down the Alt key and entering the three-digit decimal Alt keycode on the numpad. The following tables show code page 437, each character is shown with its equivalent Unicode code point and its decimal code point. See also the notes below as there are multiple equivalent Unicode characters for some code points, the decimal codes are also known as Alt codes. Although the ROM provides a graphic for all 256 different possible 8-bit codes, some APIs will not print some code points, in particular the range 1-31, instead they will interpret them as control characters. For instance many methods of outputting text on the original IBM PC would interpret the codes for BEL, BS, CR, many printers were also unable to print these characters. Legend, When translating to Unicode it should be noted that some codes do not have a unique, single Unicode equivalent and we were also fascinated by dedicated word processors from Wang, because we believed that general-purpose machines could do that just as well. Thats why, when it time to design the keyboard for the IBM PC, we put the funny Wang character set into the machine—you know, smiley faces and boxes and triangles. We were thinking wed like to do a clone of Wang word-processing software someday, according to an interview with David J. Bradley the characters were decided upon during a four-hour meeting on a plane trip from Seattle to Atlanta by Andy Saenz, Lew Eggebrecht and himself. The selection of characters has some internal logic, Table rows 0 and 1. The isolated character 127 also belongs to this group, Table rows 2 to 7, codes 32 to 126, are the standard ASCII printable characters
38.
Menu (computing)
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In computing and telecommunications, a menu or menu bar is graphical control element. It is a list of options or commands presented to an operator by a computer or communications system, entering the appropriate short-cut selects a menu item. A more sophisticated solution offers navigation using the keys or the mouse. The current selection is highlighted and can be activated by pressing the enter key, a computer using a graphical user interface presents menus with a combination of text and symbols to represent choices. By clicking on one of the symbols or text, the operator is selecting the instruction that the symbol represents, a context menu is a menu in which the choices presented to the operator are automatically modified according to the current context in which the operator is working. A common use of menus is to provide convenient access to various such as saving or opening a file, quitting a program. Most widget toolkits provide some form of pull-down or pop-up menu, according to traditional human interface guidelines, menu names were always supposed to be verbs, such as file, edit and so on. This has been ignored in subsequent user interface developments. A single-word verb however is unclear, and so as to allow for multiple word menu names. Menus are now seen in consumer electronics, starting with TV sets and VCRs that gained on-screen displays in the early 1990s. Menus allow the control of settings like tint, brightness, contrast, bass and treble, other more recent electronics in the 2000s also have menus, such as digital media players. Menus are sometimes hierarchically organized, allowing navigation through different levels of the menu structure, selecting a menu entry with an arrow will expand it, showing a second menu with options related to the selected entry. Usability of sub-menus has been criticized as difficult, because of the height that must be crossed by the pointer. The steering law predicts that this movement will be slow, federal Standard 1037C Drop-down menu Hamburger button Pie menu Radio button WIMP MenUA, A Design Space of Menu Techniques Site that discusses various menu design techniques
39.
Window (computing)
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In computing, a window is a graphical control element. It consists of an area containing some of the graphical user interface of the program it belongs to and is framed by a window decoration. It usually has a shape that can overlap with the area of other windows. It displays the output of and may allow input to one or more processes, Windows are primarily associated with graphical displays, where they can be manipulated with a pointer by employing some kind of pointing device. Text-only displays can also support windowing, as a way to multiple independent display areas. Text windows are controlled by keyboard, though some also respond to the mouse. A graphical user interface using windows as one of its main metaphors is called a system, whose main components are the display server. The idea was developed at the Stanford Research Institute and their earliest systems supported multiple windows, but there was no obvious way to indicate boundaries between them. Research continued at Xerox Corporations Palo Alto Research Center / PARC, during the 1980s the term WIMP, which stands for window, icon, menu, pointer, was coined at PARC. Apple had worked with PARC briefly at that time, apple developed an interface based on PARCs interface. It was first used on Apples Lisa and later Macintosh computers, Microsoft was developing office applications for the Mac at that time. Some speculate that this gave access to Apples OS before it was released. Windows are two dimensional objects arranged on a called the desktop. In a modern full-featured windowing system they can be resized, moved, hidden, Windows usually include other graphical objects, possibly including a menu-bar, toolbars, controls, icons and often a working area. In the working area, the document, image, folder contents or other object is displayed. Around the working area, within the window, there may be other smaller window areas, sometimes called panes or panels. The working area of a single document interface holds only one main object, child windows in multiple document interfaces, and tabs for example in many web browsers, can make several similar documents or main objects available within a single main application window. Some windows in Mac OS X have a feature called a drawer, applications that can run either under a graphical user interface or in a text user interface may use different terminology
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Dialog box
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The graphical control element dialog box is a small window that communicates information to the user and prompts them for a response. Dialog boxes are classified as modal or modeless, depending on whether they block interaction with the software that initiated the dialog, the type of dialog box displayed is dependent upon the desired user interaction. An example of a box is the about box found in many software programs, which usually displays the name of the program, its version number. Non-modal or modeless dialog boxes are used when the information is not essential to continue. In general, good software design calls for dialogs to be of this type where possible, an example might be a dialog of settings for the current document, e. g. the background and text colors. The user can continue adding text to the main window whatever color it is, usability practitioners generally regard modal dialogs as bad design-solutions, since they are prone to produce mode errors. Dangerous actions should be undoable wherever possible, a modal alert dialog that appears unexpectedly or which is dismissed automatically will not protect from the dangerous action, a modal dialog interrupts the main workflow. This effect has either been sought by the developer because it focuses on the completion of the task at hand or rejected because it prevents the user from changing to a different task when needed. The concept of a document modal dialog has recently used, most notably in OS X. In the first case, they are shown as sheets attached to a parent window and these dialogs block only that window until the user dismisses the dialog, permitting work in other windows to continue, even within the same application. In OS X, dialogs appear to emanate from a slot in their parent window and this helps to let the user understand that the dialog is attached to the parent window, not just shown in front of it. The OS X dialog box blocks the parent window, preventing the user from referring to it while interacting with the dialog and this may require the user to close the dialog to access the necessary information, then re-open the dialog box to continue
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