Apple Pencil is a line of wireless stylus pen accessories developed by Apple Inc. for use with supported iPad tablet computers. The Apple Pencil was first unveiled alongside the first-generation iPad Pro on September 9, 2015, it communicates wirelessly via Bluetooth, has a removable cap that conceals a Lightning connector used for charging. A second-generation model was unveiled in 2018, is compatible with the third-generation iPad Pro, it features minor design changes over the original version, including touch-sensitive areas that can be tapped to perform actions within supported apps, charging via the magnetic "Smart Connector" rather than a physical connection. The Apple Pencil has pressure sensitivity and angle detection, was designed for low latency to enable smooth inking on the screen; the Pencil and one's fingers can be used while rejecting input from the user's palm. One end of the device has a magnetically-fastened removable cap. Underneath this cap is the Lightning connector, which allows the Pencil's battery to be recharged via an iPad's Lightning port itself.
The initial charge lasts about 12 hours, but 15 seconds plugged into the Lightning connector of the iPad provides sufficient power for 30 minutes of use. The user can use the included female-to-female Lightning adapter to charge via a standard Lightning cable instead. Apple has promoted the Pencil as being oriented towards creative productivity; the Apple Pencil utilizes an STMicroelectronics STM32L151UCY6 Ultra-low-power 32-bit RISC ARM-based Cortex-M3 MCU running at 32 MHz with 64 KB of flash memory, a Bosch Sensortech BMA280 3‐axis accelerometer and a Cambridge Silicon Radio CSR1012A05 Bluetooth Smart IC for its Bluetooth connection to the iPad. It is powered by a recyclable rechargeable 3.82 0.329 Wh lithium-ion battery. In October 2018, Apple unveiled a new iteration of the Pencil, designed for use with the newly-unveiled third-generation iPad Pro, it is similar in design and specifications to the first iteration, but removing the detachable connector, having part of the device be flattened to inhibit rolling.
As the third-generation iPad Pro uses USB-C instead of Lightning, it is now paired and charged using the magnetic "Smart Connector" on the side of the tablet. It contains tap-sensitive zones on its sides that can be mapped to functions within apps. Custom laser engraving is available when purchased via Apple.com. A number of third-parties have produced styluses for the iPad. However, there has not been a consistent technological implementation of pressure sensitivity, palm rejection, or angle detection, leading to delayed reaction times and inaccurate strokes; each third-party manufacturer has implemented its own hardware and software approaches, resulting in a fragmented market with styli and apps having differing functionalities. For instance, a particular stylus may be designed to offer pressure sensitivity, but any given app must implement such functionality for it to work. FiftyThree produces an unrelated stylus known as Pencil, for use with its Paper drawing app for iPad. Other popular styli include products made by Adonit.
On March 27, 2018, Logitech previewed a stylus designed for the 2018 9.7-inch iPad. Using a proprietary undisclosed connection method that does not require pairing as the Apple Pencil does, this non-touch-sensitive stylus has angle detection and is designed for the education market, with a thicker design and oval cross-section shape to prevent it from rolling off of desks. Previous third-party styli have been limited by previous-generation iPad hardware without dedicated stylus connectivity, resulting in higher latency, it is expected to sell for half the price of the Apple pencil, but will be only sold through education channels. The Crayon is not compatible with current models of the iPad Pro. Surface Pen Microsoft Tablet PC Samsung Galaxy Note series List of iPad accessories Pen computing Apple Pencil
C++ is a general-purpose programming language, developed by Bjarne Stroustrup as an extension of the C language, or "C with Classes". It has imperative, object-oriented and generic programming features, while providing facilities for low-level memory manipulation, it is always implemented as a compiled language, many vendors provide C++ compilers, including the Free Software Foundation, Intel, IBM, so it is available on many platforms. C++ was designed with a bias toward system programming and embedded, resource-constrained software and large systems, with performance and flexibility of use as its design highlights. C++ has been found useful in many other contexts, with key strengths being software infrastructure and resource-constrained applications, including desktop applications and performance-critical applications. C++ is standardized by the International Organization for Standardization, with the latest standard version ratified and published by ISO in December 2017 as ISO/IEC 14882:2017.
The C++ programming language was standardized in 1998 as ISO/IEC 14882:1998, amended by the C++03, C++11 and C++14 standards. The current C++ 17 standard supersedes these with an enlarged standard library. Before the initial standardization in 1998, C++ was developed by Danish computer scientist Bjarne Stroustrup at Bell Labs since 1979 as an extension of the C language. C++20 is the next planned standard, keeping with the current trend of a new version every three years. In 1979, Bjarne Stroustrup, a Danish computer scientist, began work on "C with Classes", the predecessor to C++; the motivation for creating a new language originated from Stroustrup's experience in programming for his Ph. D. thesis. Stroustrup found that Simula had features that were helpful for large software development, but the language was too slow for practical use, while BCPL was fast but too low-level to be suitable for large software development; when Stroustrup started working in AT&T Bell Labs, he had the problem of analyzing the UNIX kernel with respect to distributed computing.
Remembering his Ph. D. experience, Stroustrup set out to enhance the C language with Simula-like features. C was chosen because it was general-purpose, fast and used; as well as C and Simula's influences, other languages influenced C++, including ALGOL 68, Ada, CLU and ML. Stroustrup's "C with Classes" added features to the C compiler, including classes, derived classes, strong typing and default arguments. In 1983, "C with Classes" was renamed to "C++", adding new features that included virtual functions, function name and operator overloading, constants, type-safe free-store memory allocation, improved type checking, BCPL style single-line comments with two forward slashes. Furthermore, it included the development of a standalone compiler for Cfront. In 1985, the first edition of The C++ Programming Language was released, which became the definitive reference for the language, as there was not yet an official standard; the first commercial implementation of C++ was released in October of the same year.
In 1989, C++ 2.0 was released, followed by the updated second edition of The C++ Programming Language in 1991. New features in 2.0 included multiple inheritance, abstract classes, static member functions, const member functions, protected members. In 1990, The Annotated C++ Reference Manual was published; this work became the basis for the future standard. Feature additions included templates, namespaces, new casts, a boolean type. After the 2.0 update, C++ evolved slowly until, in 2011, the C++11 standard was released, adding numerous new features, enlarging the standard library further, providing more facilities to C++ programmers. After a minor C++14 update released in December 2014, various new additions were introduced in C++17, further changes planned for 2020; as of 2017, C++ remains the third most popular programming language, behind Java and C. On January 3, 2018, Stroustrup was announced as the 2018 winner of the Charles Stark Draper Prize for Engineering, "for conceptualizing and developing the C++ programming language".
According to Stroustrup: "the name signifies the evolutionary nature of the changes from C". This name is credited to Rick Mascitti and was first used in December 1983; when Mascitti was questioned informally in 1992 about the naming, he indicated that it was given in a tongue-in-cheek spirit. The name comes from C's ++ operator and a common naming convention of using "+" to indicate an enhanced computer program. During C++'s development period, the language had been referred to as "new C" and "C with Classes" before acquiring its final name. Throughout C++'s life, its development and evolution has been guided by a set of principles: It must be driven by actual problems and its features should be useful in real world programs; every feature should be implementable. Programmers should be free to pick their own programming style, that style should be supported by C++. Allowing a useful feature is more important than preventing every possible misuse of C++, it should provide facilities for organising programs into separate, well-defined parts, provide facilities for combining separately developed parts.
No implicit violations of the type system (but allow explicit violations.
IPad is a line of tablet computers designed and marketed by Apple Inc. which run the iOS mobile operating system. The first iPad was released on April 3, 2010; as of May 2017, Apple has sold more than 360 million iPads, though sales peaked in 2013. It is the most popular tablet computer by sales as of the second quarter of 2018; the user interface is built around the device's multi-touch screen, including a virtual keyboard. All iPads can connect via Wi-Fi. IPads can shoot video, take photos, play music, perform Internet functions such as web-browsing and emailing. Other functions – games, reference, GPS navigation, social networking, etc. – can be enabled by downloading and installing apps. As of March 2016, the App Store has more than million apps for the iPad by third parties. There have been eight versions of the iPad; the first generation established design precedents. The 2nd-generation iPad introduced a new thinner design, a dual-core Apple A5 processor, VGA front-facing and 720p rear-facing cameras designed for FaceTime video calling.
The third generation added a Retina Display, the new Apple A5X processor with a quad-core graphics processor, a 5-megapixel camera, HD 1080p video recording, voice dictation, 4G. The fourth generation added the Apple A6X processor and replaced the 30-pin connector with an all-digital Lightning connector; the iPad Air added the Apple A7 processor and the Apple M7 motion coprocessor, reduced the thickness for the first time since the iPad 2. The iPad Air 2 added the Apple A8X processor, the Apple M8 motion coprocessor, an 8-megapixel camera, the Touch ID fingerprint sensor; the iPad introduced in 2017 added the Apple A9 processor, while sacrificing some of the improvements the iPad Air 2 introduced in exchange for a lower launch price. There have been five versions of the iPad Mini; the first generation has similar internal specifications to the iPad 2 but uses the Lightning connector instead. The iPad Mini 2 added the Retina Display, the Apple A7 processor, the Apple M7 motion coprocessor matching the internal specifications of the iPad Air.
The iPad Mini 3 added the Touch ID fingerprint sensor. The iPad Mini 4 features the Apple M8 motion coprocessor; the 5th generation features the Apple A12 SoC. There have been three generations of the iPad Pro; the first generation came with 9.7" and 12.9" screen sizes, while the second came with 10.5" and 12.9" sizes, the third with 11" and 12.9" sizes. The iPad Pros have unique features such as the Smart Connector, which are exclusive to this series of iPads. Apple co-founder Steve Jobs said in a 1983 speech that the company's strategy was simple: "What we want to do is we want to put an great computer in a book that you can carry around with you and learn how to use in 20 minutes... and we want to do it with a radio link in it so you don't have to hook up to anything and you're in communication with all of these larger databases and other computers." Apple's first tablet computer was the Newton MessagePad 100, introduced in 1993, powered by an ARM6 processor core developed by ARM, a 1990 spinout of Acorn Computers in which Apple invested.
Apple developed a prototype PowerBook Duo based tablet, the PenLite, but decided not to sell it in order to avoid hurting MessagePad sales. Apple released several more Newton-based PDAs. Apple re-entered the mobile-computing markets in 2007 with the iPhone. Smaller than the iPad, but featuring a camera and mobile phone, it pioneered the multi-touch finger-sensitive touchscreen interface of Apple's iOS mobile operating system. By late 2009, the iPad's release had been rumored for several years; such speculation talked about "Apple's tablet". The iPad was announced on January 27, 2010, by Steve Jobs at an Apple press conference at the Yerba Buena Center for the Arts in San Francisco. Jobs said that Apple had begun developing the iPad before the iPhone. Jonathan Ive in 1991 had created an industrial design for a stylus-based tablet, the Macintosh Folio, as his first project for Apple. Ive stated that after seeking to produce the tablet first, he came to agree with Jobs that the phone was more important, as the tablet's innovations would work as well in it.
The iPad's internal codename was K48, revealed in the court case surrounding leaking of iPad information before launch. Apple began taking pre-orders for the first-generation iPad on March 12, 2010; the only major change to the device between its announcement and being available to pre-order was the change of the behavior of the side switch to perform either sound muting or screen rotation locking. The Wi-Fi version of the iPad went on sale in the United States on April 3, 2010; the Wi-Fi + 3G version was released on April 30. 3G service in the United States is provided by AT&T and was sold with two prepaid contract-free data plan options: one for unlimited data and the other for 250 MB per month at half the price. On June 2, 2010, AT&T announced that effective June 7 the unlimited plan would be replaced for new
IOS 12 is the twelfth and current major release of the iOS mobile operating system developed by Apple Inc. being the successor to iOS 11. It was announced at the company's Worldwide Developers Conference on June 4, 2018, it is similar in aesthetics to iOS 11 but contains numerous performance and battery life improvements and security updates, in addition to added functionalities within native applications. It was released to the public on September 17, 2018. IOS 12 was introduced by Craig Federighi at the Apple Worldwide Developers Conference keynote address on June 4, 2018; the first developer beta version was released after the keynote presentation, with the first public beta releasing three weeks after on June 25, 2018. IOS 12.0.1 was released on October 8, 2018, as the first update to iOS 12. IOS 12.1 was released on October 30, 2018. The update included new emoji, the Group FaceTime feature, L3/R3 button support for MFi controllers, updates to the Measure app, the ability to use an eSIM on the iPhone XS Max, iPhone XS, iPhone XR. iOS 12.1.1 was released on December 5, 2018.
IOS 12.1.2 was released on December 17, 2018, is an iPhone-only update. IPads and the 6th generation iPod touch continued to use iOS 12.1.1. IOS 12.1.3 was released on January 22, 2019, featured important bug fixes patching all known kernel exploits. IOS 12.1.4 was released on February 7, 2019, featured an important bug fix concerning Group FaceTime. IOS 12.2 was contained an updated News app and 51 security fixes. This update patched the hyphen bug and added support for the 2nd Generation AirPods. Performance optimizations were made in order to speed up common tasks across all supported iOS devices. Tests done by Apple on an iPhone 6 Plus showed apps launching 40 percent faster, the system keyboard activating 50 percent faster, the camera opening 70 percent faster. Screen Time is a new feature in iOS 12; the feature displays the amount of time the user used particular apps, the amount of time the user used particular categories of apps, the number of notifications the user received. Screen Time provides blocking features to limit usage of apps or set other restrictions such as on purchases or explicit content.
It replaces Parental Controls in the iOS Settings app, but can be used by adults to limit their own usage. These features can be used without a passcode. Without setting a passcode, the limits can be bypassed but may serve as a useful reminder of usage goals. A dedicated application in iOS 12 allows users to set up Shortcuts, automated actions that the user can ask Siri to perform, it replaces the Workflow app that Apple acquired in March 2017. ARKit now allows users to share their view with other iOS 12-supported devices. ARKit 2 additionally allows full 2D image tracking and incorporates the ability to detect 3D objects. CarPlay can now run third-party navigation applications; the Voice Memos and Stocks apps are now available for iPads. Control Center is separated from the app switcher on iPad and can be opened with a swipe down on the top right corner. In addition, iPhone X-style gestures are introduced across all iPads running iOS 12. In iOS 12, the trackpad mode is enabled by long-pressing the space bar on devices without 3D Touch.
For devices with gesture navigation and no home button, users can now force quit applications by swiping up from the bottom of the screen. Messages in iOS 12 introduces a new type of customizable Animoji called "Memoji" which allows a user to create a 3D character of themselves. Apple introduced Koala, Ghost and T-Rex Animojis. In addition, Apple added new text and GIF effects similar to those found on other social media applications. FaceTime gains support for Animoji and Memoji, as well as new text and GIF effects similar to those found on other social media applications and in the Messages application.iOS 12.1, released on October 30, 2018, adds the ability to include up to 32 people in a FaceTime conversation. This feature is only supported with video by devices with the Apple Apple A9 chip or later. Group FaceTime was disabled on January 28, 2019 due to a software bug that allowed calls to be answered by the caller rather the recipient, allowing video and audio to transmitted unless the call was declined.
The functionality was restored on February 7, 2019 with the release of iOS 12.1.4. Group FaceTime remains disabled on devices running earlier versions of iOS 12. Measure is a new native AR application, it works as a level, a feature, packaged as part of the Compass app. Apple Photos has been redesigned with four new tabs, including "Photos", "For You", "Albums", "Search"; the new "For You" tab replaces the "Memories" tab found in iOS 11 and makes sharing recommendations, creates short length video collages, photo editing suggestions, as well as featured photos from a specific day. While the "Photos" and "Albums" tabs received only a few cosmetic changes, the "Search" tab includes new Artificial Intelligence and Machine Learning features which show the user photos by place and categories. Notifications are now grouped by application and have a "manage" button to turn off notifications for that app or to deliver them right from the notification center without having to go into the Settings application.
The user interface, in the industrial design field of human–computer interaction, is the space where interactions between humans and machines occur. The goal of this interaction is to allow effective operation and control of the machine from the human end, whilst the machine feeds back information that aids the operators' decision-making process. Examples of this broad concept of user interfaces include the interactive aspects of computer operating systems, hand tools, heavy machinery operator controls, process controls; the design considerations applicable when creating user interfaces are related to or involve such disciplines as ergonomics and psychology. The goal of user interface design is to produce a user interface which makes it easy and enjoyable to operate a machine in the way which produces the desired result; this means that the operator needs to provide minimal input to achieve the desired output, that the machine minimizes undesired outputs to the human. User interfaces are composed of one or more layers including a human-machine interface interfaces machines with physical input hardware such a keyboards, game pads and output hardware such as computer monitors and printers.
A device that implements a HMI is called a human interface device. Other terms for human-machine interfaces are man–machine interface and when the machine in question is a computer human–computer interface. Additional UI layers may interact with one or more human sense, including: tactile UI, visual UI, auditory UI, olfactory UI, equilibrial UI, gustatory UI. Composite user interfaces are UIs that interact with two or more senses; the most common CUI is a graphical user interface, composed of a tactile UI and a visual UI capable of displaying graphics. When sound is added to a GUI it becomes a multimedia user interface. There are three broad categories of CUI: standard and augmented. Standard composite user interfaces use standard human interface devices like keyboards and computer monitors; when the CUI blocks out the real world to create a virtual reality, the CUI is virtual and uses a virtual reality interface. When the CUI does not block out the real world and creates augmented reality, the CUI is augmented and uses an augmented reality interface.
When a UI interacts with all human senses, it is called a qualia interface, named after the theory of qualia. CUI may be classified by how many senses they interact with as either an X-sense virtual reality interface or X-sense augmented reality interface, where X is the number of senses interfaced with. For example, a Smell-O-Vision is a 3-sense Standard CUI with visual display and smells; the user interface or human–machine interface is the part of the machine that handles the human–machine interaction. Membrane switches, rubber keypads and touchscreens are examples of the physical part of the Human Machine Interface which we can see and touch. In complex systems, the human–machine interface is computerized; the term human–computer interface refers to this kind of system. In the context of computing, the term extends as well to the software dedicated to control the physical elements used for human-computer interaction; the engineering of the human–machine interfaces is enhanced by considering ergonomics.
The corresponding disciplines are human factors engineering and usability engineering, part of systems engineering. Tools used for incorporating human factors in the interface design are developed based on knowledge of computer science, such as computer graphics, operating systems, programming languages. Nowadays, we use the expression graphical user interface for human–machine interface on computers, as nearly all of them are now using graphics. There is a difference between a user interface and an operator interface or a human–machine interface; the term "user interface" is used in the context of computer systems and electronic devices Where a network of equipment or computers are interlinked through an MES -or Host to display information. A human-machine interface is local to one machine or piece of equipment, is the interface method between the human and the equipment/machine. An operator interface is the interface method by which multiple equipment that are linked by a host control system is accessed or controlled.
The system may expose several user interfaces to serve different kinds of users. For example, a computerized library database might provide two user interfaces, one for library patrons and the other for library personnel; the user interface of a mechanical system, a vehicle or an industrial installation is sometimes referred to as the human–machine interface. HMI is a modification of the original term MMI. In practice, the abbreviation MMI is still used although some may claim that MMI stands for something different now. Another abbreviation is HCI, but is more used for human–computer interaction. Other terms used are operator interface terminal; however it is abbreviated, the terms refer to the'layer' that separates a human, operating a machine from the machine itself. Without a clean and usable interface, humans would not be able to
IPad (1st generation)
The first-generation iPad is a tablet computer designed and marketed by Apple Inc. as the first in the iPad line. The device features an Apple A4 processor, a 9.7" touchscreen display, and, on certain variants, the capability of accessing cellular networks. Using the iOS operating system, the iPad can play music and receive email and browse the web. Other functions, which include the ability to play games and access references, GPS navigation software and social network services can be enabled by downloading apps; the device was unveiled on January 27, 2010 at a media conference. On April 3, 2010, the Wi-Fi variant of the device was released in the United States, followed by the release of the Wi-Fi + Cellular variant on April 30. On May 28, it was released in Australia, France, Italy, Spain and the United Kingdom; the device received positive reviews from various technology blogs and publications. Reviewers praised the device for its wide range of capabilities and labelled it as a competitor to laptops and netbooks.
Some aspects were criticized, including the closed nature of the operating system and the lack of support for the Adobe Flash multimedia format. During the first 80 days, three million iPads were sold. By the launch of the iPad 2, Apple sold more than 15 million iPads. On March 2, 2011, Apple reduced the price of the first-generation iPad. Apple co-founder Steve Jobs stated in a 1983 speech that his company’s “Strategy is simple. What we want to do at Apple, is we want to put an great computer in a book that you can carry around with you and learn how to use in 20 minutes... And we want to do it with a radio link in it so you don’t have to hook up to anything and you’re in communication with all of these larger databases and other computers.” Apple’s first tablet computer was the Newton MessagePad 100, introduced in 1993, which led to the creation of the ARM6 processor core with Acorn Computers. Apple developed a prototype PowerBook Duo-based tablet, the PenLite, but decided not to sell it in order to avoid hurting MessagePad sales.
Apple released several more Newton-based PDAs. Apple reentered the mobile-computing market in 2007 with the iPhone. Smaller than the iPad and featuring a camera and mobile phone, it pioneered the multitouch finger-sensitive touchscreen interface of Apple’s iOS mobile operating system. By late 2009, the iPad's release had been rumored for several years; such speculation talked about “Apple’s tablet”. The actual name is an homage to the Star Trek PADD, a fictional device similar in appearance to the iPad; the iPad was announced on January 27, 2010, by Jobs at an Apple press conference at the Yerba Buena Center for the Arts in San Francisco. Jobs said that Apple began developing the iPad before the iPhone, but temporarily shelved the effort upon realizing that its ideas would work just as well in a mobile phone; the iPad’s internal codename was K48, revealed in the court case surrounding leaking of iPad information before launch. Apple began taking pre-orders for the iPad from US customers on March 12, 2010.
The only major change to the device between its announcement and being available to pre-order was the change of the behavior of the side switch from sound muting to that of a screen rotation lock. The Wi-Fi version of the iPad went on sale in the United States on April 3, 2010; the Wi-Fi + 3G version was released on April 30. 3G service for the iPad in the United States is provided by AT&T and was sold with two prepaid contract-free data plan options: one for unlimited data and the other for 250 MB per month at half the price. On June 2, 2010, AT&T announced that, effective June 7, the unlimited plan would be replaced for new customers with a 2 GB plan at lower cost; the plans can be cancelled at any time. The iPad was only available for purchase on Apple’s online store and its retail locations; the iPad was launched in countries including Australia, France, Germany and the United Kingdom on May 28. Online pre-orders in those countries began on May 10. Apple released the iPad in Hong Kong, Mexico, New Zealand and Singapore on July 23, 2010.
Israel prohibited importation of the iPad because of concerns that its Wi-Fi might interfere with other devices. On September 17, 2010, the iPad was launched in China; the iPad shipped with iPhone OS 3.2. On September 1, 2010, it was announced the iPad would get iOS 4.2 by November 2010. It comes with several applications, including Safari, Photos, Video, iPod, iTunes, App Store, Notes and Contacts. Several are improved versions of applications developed for the Mac; the iPad syncs with iTunes on a Mac or Windows PC. Apple ported its iWork suite from the Mac to the iPad, sells pared-down versions of Pages and Keynote apps in the App Store. Although the iPad is not designed to replace a mobile phone, a user can use a wired headset or the built-in speaker and microphone to place phone calls over Wi-Fi or 3G using a VoIP application. On October 12, 2011, iOS 5 was released to various iOS devices, including the first-generation iPad, was downloadable through iTunes; the update was reported to contain hundreds of new features and tweaks, including Twitter integration, Notification Center and iMessage, a feature th
In computing, a keyboard shortcut is a series of one or several keys, such as "Ctrl+F" to search a character string. Such a directive invokes a operating system operation when triggered by the user; the meaning of term "keyboard shortcut" can vary depending on software manufacturer. For instance, Microsoft differentiates keyboard shortcuts from hotkeys whereby the former consists of a specific key combination used to trigger an action, the latter represents a designated letter in a menu command or toolbar button that when pressed together with the Alt key, activates such command—whereas a "hotkey" on Windows is a system wide shortcut, always available in all contexts as long as the program responsible for it is running and not suspended. Keyboard shortcuts are a means for invoking one or more commands using the keyboard that would otherwise be accessible only through a menu, a pointing device, different levels of a user interface, or via a command-line interface. Keyboard shortcuts are used to expedite common operations by reducing input sequences to a few keystrokes, hence the term "shortcut".
To differentiate from general keyboard input, most keyboard shortcuts require the user to press and hold several keys or a sequence of keys one after the other. Unmodified key presses are sometimes accepted when the keyboard is not used for general input - such as with graphics packages e.g. Adobe Photoshop or IBM Lotus Freelance Graphics. Other keyboard shortcuts use function keys that are dedicated for use in shortcuts and may only require a single keypress. For simultaneous keyboard shortcuts, one first holds down the modifier key quickly presses and releases the regular key, releases the modifier key; this distinction is important, as trying to press all the keys will either miss some of the modifier keys, or cause unwanted auto-repeat. Sequential shortcuts involve pressing and releasing a dedicated prefix key, such as the Esc key, followed by one or more keystrokes. Mnemonics are distinguishable from keyboard shortcuts. One difference between them is that the keyboard shortcuts are not localized on multi-language software but the mnemonics are localized to reflect the symbols and letters used in the specific locale.
In most GUIs, a program's keyboard shortcuts are discoverable by browsing the program's menus – the shortcut is indicated next to the menu choice. There are keyboards that have the shortcuts for a particular application marked on them; these keyboards are used for editing video, audio, or graphics, as well as in software training courses. There are stickers with shortcuts printed on them that can be applied to a regular keyboard. Reference cards intended to be propped up in the user's workspace exist for many applications. In the past, when computer hardware was more standardized, it was common for computer books and magazines to print cards that were cut out, intended to be placed over the user's keyboard with the printed shortcuts noted next to the appropriate keys; when shortcuts are referred to as key assignments it carries the connotation that the shortcuts are customizable to a user's preference and that program functions may be'bound' to a different set of keystrokes instead of or in addition to the default.
This highlights a difference in philosophy regarding shortcuts. Some systems end-user-oriented systems such as Mac OS or Windows, consider standardized shortcuts essential to the environment's ease of use; these systems limit a user's ability to change shortcuts even requiring a separate or third-party utility to perform the task. Other systems Unix and related, consider shortcuts to be a user's prerogative, that they should be changeable to suit individual preference. In most real-world environments, both philosophies co-exist; the motivations for customizing key assignments vary. Users new to a program or software environment may customize the new environment's layout to be similar to another environment with which they are more familiar. More advanced users may customize key bindings to better suit their workflow, adding shortcuts for their used actions and deleting or replacing bindings for less-used functions. Hardcore gamers customize their key bindings in order to increase performance via faster reaction times.
The original Macintosh User Interface Guidelines defined a set of keyboard shortcuts that would remain consistent across application programs. This provides a better user experience than the situation then-prevalent one of applications using the same keys for different functions; this could result in user errors if one program used ⌘ Command+D to mean Delete while another used it to Duplicate an item. The standard bindings were: ⌘ Q: Quit ⌘ W: Close Window ⌘ B: Bold text ⌘ I: Italicize text ⌘ U: Underline text ⌘ O: Open ⌘ P: Print ⌘ A: Select All ⌘ S: Save ⌘ F: Find ⌘ G: Find Again ⌘ Z: Undo ⌘ X: Cut ⌘ C: Copy ⌘ V: Paste (resembles an arrow pointing downward "in