68-532: The Qt Project is an open collaboration effort to coordinate the development of the Qt software framework . Initially founded by Nokia in 2011, the project is now led by The Qt Company . Haavard Nord and Eirik Chambe-Eng (the original developers of Qt and the CEO and President, respectively, of Trolltech ) began development of "Qt" in 1991, three years before the company was incorporated as Quasar Technologies, then changed
136-427: A declarative scripting language called QML that allows using JavaScript to provide the logic. With Qt Quick, rapid application development for mobile devices became possible, while logic can still be written with native code as well to achieve the best possible performance. Other features include SQL database access, XML parsing, JSON parsing, thread management and network support. The latest version of
204-776: A complete system - consisting of multiple processors, multipliers, caches, even different types of memory and commonly various peripherals like interfaces for wired or wireless communication on a single chip. Often graphics processing units (GPU) and DSPs are included such chips. SoCs can be implemented as an application-specific integrated circuit (ASIC) or using a field-programmable gate array (FPGA) which typically can be reconfigured. ASIC implementations are common for very-high-volume embedded systems like mobile phones and smartphones . ASIC or FPGA implementations may be used for not-so-high-volume embedded systems with special needs in kind of signal processing performance, interfaces and reliability, like in avionics. Embedded systems talk with
272-415: A dedicated function within a larger mechanical or electronic system. It is embedded as part of a complete device often including electrical or electronic hardware and mechanical parts. Because an embedded system typically controls physical operations of the machine that it is embedded within, it often has real-time computing constraints. Embedded systems control many devices in common use. In 2009 , it
340-479: A heavy user of Qt, the KDE project submits many patches and features from its developer library KDE Frameworks back to Qt. Qt Wiki provides a comprehensive list of English books about Qt. This is a list of notable books: Embedded system An embedded system is a specialized computer system —a combination of a computer processor , computer memory , and input/output peripheral devices—that has
408-555: A myriad of things in the physical world and act on this information through monitoring and control systems. These motes are completely self-contained and will typically run off a battery source for years before the batteries need to be changed or charged. Embedded systems are designed to perform a specific task, in contrast with general-purpose computers designed for multiple tasks. Some have real-time performance constraints that must be met, for reasons such as safety and usability; others may have low or no performance requirements, allowing
476-567: A non-GUI program using Qt is the Cutelyst web framework . Qt supports various C++ compilers, including the GCC and Clang C++ compilers and the Visual Studio suite. It supports other languages with bindings or extensions, such as Python via Python bindings and PHP via an extension for PHP5, and has extensive internationalization support. Qt also provides Qt Quick , that includes
544-656: A number of other organizations participate in the Qt Project. Second-largest Qt contributor is KDAB , a Swedish Qt consulting company. KDAB is involved in many areas, including maintenance of several components. KDAB together with RIM/BlackBerry are maintaining the QNX and BlackBerry 10 ports of Qt. Another big participator is Intel , contributing for example Wayland support. AudioCodes maintains IBM ClearCase support in Qt Creator . Many contributions also come from
612-458: A simple menu system . More sophisticated devices that use a graphical screen with touch sensing or screen-edge soft keys provide flexibility while minimizing space used: the meaning of the buttons can change with the screen, and selection involves the natural behavior of pointing at what is desired. Some systems provide user interface remotely with the help of a serial (e.g. RS-232 ) or network (e.g. Ethernet ) connection. This approach extends
680-500: A single microcontroller chip, to very high with multiple units, peripherals and networks, which may reside in equipment racks or across large geographical areas connected via long-distance communications lines. The origins of the microprocessor and the microcontroller can be traced back to the MOS integrated circuit , which is an integrated circuit chip fabricated from MOSFETs (metal–oxide–semiconductor field-effect transistors ) and
748-475: A single role. Examples of devices that may adopt this approach are automated teller machines (ATM) and arcade machines , which contain code specific to the application. However, most ready-made embedded systems boards are not PC-centered and do not use the ISA or PCI busses. When a system-on-a-chip processor is involved, there may be little benefit to having a standardized bus connecting discrete components, and
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#1732787816462816-818: A software-based tracing method used in RTOS environments is the use of empty macros which are invoked by the operating system at strategic places in the code, and can be implemented to serve as hooks . Embedded systems often reside in machines that are expected to run continuously for years without error, and in some cases recover by themselves if an error occurs. Therefore, the software is usually developed and tested more carefully than that for personal computers, and unreliable mechanical moving parts such as disk drives, switches or buttons are avoided. Specific reliability issues may include: A variety of techniques are used, sometimes in combination, to recover from errors—both software bugs such as memory leaks , and also soft errors in
884-624: A specific function as a subsystem of the car itself. The program instructions written for embedded systems are referred to as firmware , and are stored in read-only memory or flash memory chips. They run with limited computer hardware resources: little memory, small or non-existent keyboard or screen. Embedded systems range from no user interface at all, in systems dedicated to one task, to complex graphical user interfaces that resemble modern computer desktop operating systems. Simple embedded devices use buttons , light-emitting diodes (LED), graphic or character liquid-crystal displays (LCD) with
952-455: A standard PC, although still quite large compared to most simple (8/16-bit) embedded systems. They may use DOS , FreeBSD , Linux , NetBSD , OpenHarmony or an embedded real-time operating system (RTOS) such as MicroC/OS-II , QNX or VxWorks . In certain applications, where small size or power efficiency are not primary concerns, the components used may be compatible with those used in general-purpose x86 personal computers. Boards such as
1020-427: A standard for programmable microcontrollers, including almost any computer-based controllers, such as single-board computers , numerical, and event-based controllers. There are several different types of software architecture in common use. In this design, the software simply has a loop which monitors the input devices. The loop calls subroutines , each of which manages a part of the hardware or software. Hence it
1088-524: Is a cross-platform IDE for C++ and QML. Qt Designer 's GUI layout/design functionality is integrated into the IDE, although Qt Designer can still be started as a standalone tool. In addition to Qt Creator, Qt provides qmake , a cross-platform build script generation tool that automates the generation of Makefiles for development projects across different platforms. There are other tools available in Qt, including
1156-419: Is a selection of operating systems, usually including Linux and some real-time choices. These modules can be manufactured in high volume, by organizations familiar with their specialized testing issues, and combined with much lower volume custom mainboards with application-specific external peripherals. Prominent examples of this approach include Arduino and Raspberry Pi . A system on a chip (SoC) contains
1224-717: Is available under the following free software licenses: GPL 2.0 , GPL 3.0 , LGPL 3.0 and LGPL 2.1 (with Qt special exception). Note that some modules are available only under a GPL license, which means that applications which link to these modules need to comply with that license. In addition, Qt has always been available under a commercial license, like the Qt Commercial License, that allows developing proprietary applications with no restrictions on licensing. Qt comes with its own set of tools to ease cross-platform development, which can otherwise be cumbersome due to different set of development tools. Qt Creator
1292-417: Is called a simple control loop or programmed input-output. Some embedded systems are predominantly controlled by interrupts . This means that tasks performed by the system are triggered by different kinds of events; an interrupt could be generated, for example, by a timer at a predefined interval, or by a serial port controller receiving data. This architecture is used if event handlers need low latency, and
1360-433: Is not a separate legal entity or organization; Digia retains all trademarks around Qt. Qt's Open Governance is modelled after WebKit's . Decision-making takes place in a process the project describes as "lazy consensus". The project facilitates online communication among its developers and community members through public forums, mailing lists, and wiki pages. Aside from the project leader Digia and various individuals,
1428-623: Is presented by a host PC tool, based on a recording of the system behavior. The trace recording can be performed in software, by the RTOS, or by special tracing hardware. RTOS tracing allows developers to understand timing and performance issues of the software system and gives a good understanding of the high-level system behaviors. Trace recording in embedded systems can be achieved using hardware or software solutions. Software-based trace recording does not require specialized debugging hardware and can be used to record traces in deployed devices, but it can have an impact on CPU and RAM usage. One example of
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#17327878164621496-422: Is purchased or provided by a person other than the manufacturer of the electronics. In these systems, an open programming environment such as Linux , NetBSD , FreeBSD , OSGi or Embedded Java is required so that the third-party software provider can sell to a large market. Embedded debugging may be performed at different levels, depending on the facilities available. Considerations include: does it slow down
1564-511: Is supported until 26 May 2025. Additionally the KDE project provides unofficial support for, at least, Qt 5.15, i.e. not just for commercial users. In 2017, the Qt Company estimated a community of about 1 million developers worldwide in over 70 industries. Graphical user-interfaces and desktop environments that utilize Qt/QML as widget toolkit: Many notable open-source or proprietary cross-platform software are using Qt or QML : Qt
1632-764: Is under the open source licenses, while the Indie Mobile, Professional and Enterprise versions, which contain additional functionality and libraries, e.g. Enterprise Controls are commercially sold by The Qt Company. Qt works on many different platforms; the following are officially supported: After Nokia opened the Qt source code to the community on Gitorious , various ports appeared. There are also some ports of Qt that may be available, but are not supported anymore. These platforms are listed in List of platforms supported by Qt . See also there for current community support for other lesser known platforms, such as SailfishOS . Qt
1700-405: Is used for developing graphical user interfaces (GUIs) and multi-platform applications that run on all major desktop platforms and mobile or embedded platforms. Most GUI programs created with Qt have a native-looking interface, in which case Qt is classified as a widget toolkit . Non-GUI programs can also be developed, such as command-line tools and consoles for servers. An example of such
1768-620: Is usually more complex than a traditional solution, most of the complexity is contained within the microcontroller itself. Very few additional components may be needed and most of the design effort is in the software. Software prototype and test can be quicker compared with the design and construction of a new circuit not using an embedded processor. Embedded systems are commonly found in consumer, industrial, automotive , home appliances , medical, telecommunication, commercial, aerospace and military applications. Telecommunications systems employ numerous embedded systems from telephone switches for
1836-422: Is utilized by a wide range of companies and organizations such as Qt is built on these key concepts: Starting with Qt 4.0 the framework was split into individual modules. With Qt 5.0 the architecture was modularized even further. Qt is now split into essential and add-on modules. There are four editions of Qt available: Community , Indie Mobile , Professional and Enterprise . The Community version
1904-489: The Intel 4004 (released in 1971), was designed for calculators and other small systems but still required external memory and support chips. By the early 1980s, memory, input and output system components had been integrated into the same chip as the processor forming a microcontroller. Microcontrollers find applications where a general-purpose computer would be too costly. As the cost of microprocessors and microcontrollers fell,
1972-463: The KDE community, which is oftentimes adding features from their KDE Frameworks upstream into Qt. Qt (framework) Qt (pronounced "cute" or as an initialism ) is a cross-platform application development framework for creating graphical user interfaces as well as cross-platform applications that run on various software and hardware platforms such as Linux , Windows , macOS , Android or embedded systems with little or no change in
2040-489: The Windows Phone platform instead (and since then support for that platform has also been dropped). One month later, Nokia announced the sale of Qt's commercial licensing and professional services to Digia, with the immediate goal of taking Qt support to Android , iOS and Windows 8 platforms, and to continue focusing on desktop and embedded development, although Nokia was to remain the main development force behind
2108-497: The source code under the Qt Free Edition License . This license was viewed as not compliant with the free software definition by Free Software Foundation because, while the source was available, it did not allow the redistribution of modified versions. Trolltech used this license until version 1.45. Controversy erupted around 1998 when it became clear that the K Desktop Environment was going to become one of
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2176-585: The GPL. A compromise was found between KDE and Trolltech whereby Qt would not be able to fall under a more restrictive license than the QPL, even if Trolltech was bought out or went bankrupt. This led to the creation of the KDE Free Qt Foundation which guarantees that Qt would fall under a BSD-style license should no free/open source version of Qt be released during a period of 12 months. In 2000, Qt 2.2
2244-606: The Nokia Qt SDK was released on 23 June 2010. The source code was made available over Gitorious, a community oriented git source code repository, with a goal of creating a broader community using and improving Qt. On 14 January 2009, Qt version 4.5 added another option, the LGPL , to make Qt more attractive for both non-GPL open source projects and closed applications. In February 2011, Nokia announced its decision to drop Symbian technologies and base their future smartphones on
2312-843: The Qt Designer interface builder and the Qt Assistant help browser (which are both embedded in Qt Creator), the Qt Linguist translation tool, uic (user interface compiler), and moc (Meta-Object Compiler). In the summer of 1990, Haavard Nord and Eirik Chambe-Eng (the original developers of Qt and the CEO and President, respectively, of Trolltech ) were working together on a database application for ultrasound images written in C++ and running on Mac OS , Unix , and Microsoft Windows . They began development of "Qt" in 1991, three years before
2380-489: The Qt Framework is Qt 6.8, which was released on October 8, 2024. Also still supported are — for commercial users — 6.5 LTS, released on April 3, 2023, 6.2 LTS, released on 30 September 2021, and 5.15 LTS, released on 26 May 2020 – long-term support (LTS) versions are generally supported for three years with a commercial license, while 5.15 support was extended to five years for subscription license holders, and so it
2448-471: The Qt business and copyrights to their wholly owned subsidiary, The Qt Company, which owns 25 brands related to Qt. In May 2016, Digia and Qt demerged completely into two independent companies. Qt 5 was officially released on 19 December 2012. This new version marked a major change in the platform, with hardware-accelerated graphics, QML and JavaScript playing a major role. The traditional C++-only QWidgets continued to be supported, but did not benefit from
2516-517: The VIA EPIA range help to bridge the gap by being PC-compatible but highly integrated, physically smaller or have other attributes making them attractive to embedded engineers. The advantage of this approach is that low-cost commodity components may be used along with the same software development tools used for general software development. Systems built in this way are still regarded as embedded since they are integrated into larger devices and fulfill
2584-447: The capabilities of the embedded system, avoids the cost of a display, simplifies the board support package (BSP) and allows designers to build a rich user interface on the PC. A good example of this is the combination of an embedded HTTP server running on an embedded device (such as an IP camera or a network router ). The user interface is displayed in a web browser on a PC connected to
2652-481: The company was incorporated as Quasar Technologies, then changed the name to Troll Tech and then to Trolltech. The toolkit was called Qt because the letter Q looked appealing in Haavard's Emacs typeface, and "t" was inspired by Xt , the X toolkit. The first two versions of Qt had only two flavors: Qt/X11 for Unix and Qt/Windows for Windows. On 20 May 1995 Trolltech publicly released Qt 0.90 for X11/Linux with
2720-476: The creation of the KDE Free Qt foundation, which guarantees that Qt would fall under a BSD-style license should no free/open source version of Qt be released during 12 months. In 2000, Qt/X11 2.2 was released under the GPL v2, ending all controversy regarding GPL compatibility . At the end of 2001, Trolltech released Qt 3.0, which added support for Mac OS X (now known as macOS ). The Mac OS X support
2788-683: The device. Examples of properties of typical embedded computers when compared with general-purpose counterparts, are low power consumption, small size, rugged operating ranges, and low per-unit cost. This comes at the expense of limited processing resources. Numerous microcontrollers have been developed for embedded systems use. General-purpose microprocessors are also used in embedded systems, but generally, require more support circuitry than microcontrollers. PC/104 and PC/104+ are examples of standards for ready-made computer boards intended for small, low-volume embedded and ruggedized systems. These are mostly x86-based and often physically small compared to
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2856-409: The environment for both hardware and software tools may be very different. One common design style uses a small system module, perhaps the size of a business card, holding high density BGA chips such as an ARM -based system-on-a-chip processor and peripherals, external flash memory for storage, and DRAM for runtime memory. The module vendor will usually provide boot software and make sure there
2924-555: The final application to be licensed under various GPL-incompatible free software / open source licenses such as the Mozilla Public License 1.1. Nokia acquired Trolltech ASA on 17 June 2008 and changed the name first to Qt Software, then to Qt Development Frameworks. Nokia focused on turning Qt into the main development platform for its devices, including a port to the Symbian S60 platform . Version 1.0 of
2992-735: The first microprocessors, as engineers began recognizing that a complete computer processor system could be contained on several MOS LSI chips. The first multi-chip microprocessors, the Four-Phase Systems AL1 in 1969 and the Garrett AiResearch MP944 in 1970, were developed with multiple MOS LSI chips. The first single-chip microprocessor was the Intel 4004 , released in 1971. It was developed by Federico Faggin , using his silicon-gate MOS technology, along with Intel engineers Marcian Hoff and Stan Mazor , and Busicom engineer Masatoshi Shima . One of
3060-650: The first recognizably modern embedded systems was the Apollo Guidance Computer , developed ca. 1965 by Charles Stark Draper at the MIT Instrumentation Laboratory . At the project's inception, the Apollo guidance computer was considered the riskiest item in the Apollo project as it employed the then newly developed monolithic integrated circuits to reduce the computer's size and weight. An early mass-produced embedded system
3128-407: The following areas: Unless restricted to external debugging, the programmer can typically load and run software through the tools, view the code running in the processor, and start or stop its operation. The view of the code may be as high-level programming language , assembly code or mixture of both. Real-time operating systems often support tracing of operating system events. A graphical view
3196-478: The framework at that time. In March 2011, Nokia sold the commercial licensing part of Qt to Digia, creating Qt Commercial. In August 2012, Digia announced that it would acquire Qt from Nokia. The Qt team at Digia started their work in September 2012. They released Qt 5.0 within a month and newer versions every six months with new features and additional supported platforms. In September 2014, Digia transferred
3264-473: The hardware: For high-volume systems such as mobile phones , minimizing cost is usually the primary design consideration. Engineers typically select hardware that is just good enough to implement the necessary functions. For low-volume or prototype embedded systems, general-purpose computers may be adapted by limiting the programs or by replacing the operating system with an RTOS. In 1978 National Electrical Manufacturers Association released ICS 3-1978,
3332-421: The leading desktop environments for Linux. As it was based on Qt, many people in the free software movement worried that an essential piece of one of their major operating systems would be proprietary. The Windows platform was available only under a proprietary license, which meant free/open source applications written in Qt for X11 could not be ported to Windows without purchasing the proprietary edition. With
3400-454: The main application, how close is the debugged system or application to the actual system or application, how expressive are the triggers that can be set for debugging (e.g., inspecting the memory when a particular program counter value is reached), and what can be inspected in the debugging process (such as, only memory, or memory and registers, etc.). From simplest to most sophisticated debugging techniques and systems are roughly grouped into
3468-559: The name to Troll Tech and then to Trolltech. Until version 1.45 the source code of Qt was released under the Qt Free Edition License . This was viewed as not compliant with the open source principle by the Open Source Initiative and the free software definition by Free Software Foundation because, while the source was available, it did not allow the redistribution of modified versions. Controversy arose around 1998 when it became clear that KDE's K Desktop Environment
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#17327878164623536-2299: The network to cell phones at the end user . Computer networking uses dedicated routers and network bridges to route data. Consumer electronics include MP3 players , television sets , mobile phones , video game consoles , digital cameras , GPS receivers, and printers . Household appliances, such as microwave ovens , washing machines and dishwashers , include embedded systems to provide flexibility, efficiency and features. Advanced heating, ventilation, and air conditioning (HVAC) systems use networked thermostats to more accurately and efficiently control temperature that can change by time of day and season . Home automation uses wired- and wireless-networking that can be used to control lights, climate, security, audio/visual, surveillance, etc., all of which use embedded devices for sensing and controlling. Transportation systems from flight to automobiles increasingly use embedded systems. New airplanes contain advanced avionics such as inertial guidance systems and GPS receivers that also have considerable safety requirements. Spacecraft rely on astrionics systems for trajectory correction. Various electric motors — brushless DC motors , induction motors and DC motors — use electronic motor controllers . Automobiles , electric vehicles , and hybrid vehicles increasingly use embedded systems to maximize efficiency and reduce pollution. Other automotive safety systems using embedded systems include anti-lock braking system (ABS), electronic stability control (ESC/ESP), traction control (TCS) and automatic four-wheel drive . Medical equipment uses embedded systems for monitoring , and various medical imaging ( positron emission tomography (PET), single-photon emission computed tomography (SPECT), computed tomography (CT), and magnetic resonance imaging (MRI) for non-invasive internal inspections. Embedded systems within medical equipment are often powered by industrial computers. Embedded systems are used for safety-critical systems in aerospace and defense industries. Unless connected to wired or wireless networks via on-chip 3G cellular or other methods for IoT monitoring and control purposes, these systems can be isolated from hacking and thus be more secure. For fire safety,
3604-469: The open development of Qt via the Qt Project. One such Qt contributor is Klarälvdalens Datakonsult AB, a Swedish Qt consulting company. KDAB is involved in many areas, including maintenance of several components. Together with RIM/BlackBerry , KDAB is maintaining the QNX and BlackBerry 10 ports of Qt. Another participator is Intel , contributing for example Wayland support. AudioCodes maintains IBM ClearCase support in Qt Creator . As
3672-539: The outside world via peripherals , such as: As with other software, embedded system designers use compilers , assemblers , and debuggers to develop embedded system software. However, they may also use more specific tools: Software tools can come from several sources: As the complexity of embedded systems grows, higher-level tools and operating systems are migrating into machinery where it makes sense. For example, cellphones , personal digital assistants and other consumer computers often need significant software that
3740-437: The performance improvements available through the new architecture. Qt 5 brings significant improvements to the speed and ease of developing user interfaces. Framework development of Qt 5 moved to open governance at qt-project.org, which made it possible for developers outside Digia to submit patches for review. Aside from The Qt Company, many organizations and individuals using Qt as their development platform participate in
3808-450: The prevalence of embedded systems increased. A comparatively low-cost microcontroller may be programmed to fulfill the same role as a large number of separate components. With microcontrollers, it became feasible to replace, even in consumer products, expensive knob-based analog components such as potentiometers and variable capacitors with up/down buttons or knobs read out by a microprocessor. Although in this context an embedded system
3876-1244: The processor(s) used may be types ranging from general purpose to those specialized in a certain class of computations, or even custom designed for the application at hand. A common standard class of dedicated processors is the digital signal processor (DSP). Since the embedded system is dedicated to specific tasks, design engineers can optimize it to reduce the size and cost of the product and increase its reliability and performance. Some embedded systems are mass-produced, benefiting from economies of scale . Embedded systems range in size from portable personal devices such as digital watches and MP3 players to bigger machines like home appliances , industrial assembly lines , robots , transport vehicles, traffic light controllers , and medical imaging systems. Often they constitute subsystems of other machines like avionics in aircraft and astrionics in spacecraft . Large installations like factories , pipelines , and electrical grids rely on multiple embedded systems networked together. Generalized through software customization, embedded systems such as programmable logic controllers frequently comprise their functional units. Embedded systems range from those low in complexity, with
3944-492: The release of version 2.0 of the toolkit in mid-1999, the license was changed to the Q Public License (QPL), a free software license, but one regarded by the Free Software Foundation as incompatible with the GPL. Compromises were sought between KDE and Trolltech whereby Qt would not be able to fall under a more restrictive license than the QPL, even if Trolltech was bought out or went bankrupt. This led to
4012-548: The system hardware to be simplified to reduce costs. Embedded systems are not always standalone devices. Many embedded systems are a small part within a larger device that serves a more general purpose. For example, the Gibson Robot Guitar features an embedded system for tuning the strings, but the overall purpose of the Robot Guitar is to play music. Similarly, an embedded system in an automobile provides
4080-540: The systems can be designed to have a greater ability to handle higher temperatures and continue to operate. In dealing with security, the embedded systems can be self-sufficient and be able to deal with cut electrical and communication systems. Miniature wireless devices called motes are networked wireless sensors. Wireless sensor networking makes use of miniaturization made possible by advanced integrated circuit (IC) design to couple full wireless subsystems to sophisticated sensors, enabling people and companies to measure
4148-486: The underlying codebase while still being a native application with native capabilities and speed. Qt is currently being developed by The Qt Company , a publicly listed company, and the Qt Project under open-source governance , involving individual developers and organizations working to advance Qt. Qt is available under both commercial licenses and open-source GPL 2.0, GPL 3.0, and LGPL 3.0 licenses. Qt
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#17327878164624216-500: Was available only in the proprietary license until June 2003, when Trolltech released Qt 3.2 with Mac OS X support available under the GPL. In 2002, members of the KDE on Cygwin project began porting the GPL licensed Qt/X11 code base to Windows. This was in response to Trolltech's refusal to license Qt/Windows under the GPL on the grounds that Windows was not a free/open source software platform. The project achieved reasonable success although it never reached production quality. This
4284-404: Was developed in the early 1960s. By 1964, MOS chips had reached higher transistor density and lower manufacturing costs than bipolar chips. MOS chips further increased in complexity at a rate predicted by Moore's law , leading to large-scale integration (LSI) with hundreds of transistors on a single MOS chip by the late 1960s. The application of MOS LSI chips to computing was the basis for
4352-411: Was estimated that ninety-eight percent of all microprocessors manufactured were used in embedded systems. Modern embedded systems are often based on microcontrollers (i.e. microprocessors with integrated memory and peripheral interfaces), but ordinary microprocessors (using external chips for memory and peripheral interface circuits) are also common, especially in more complex systems. In either case,
4420-420: Was going to become one of the leading desktop environments for Linux . As it was based on Qt, many people in the free software movement worried that an essential piece of one of their major operating systems would be proprietary. With the release of Qt 2.0, the license was changed to the Q Public License (QPL), a free software license but one regarded by the Free Software Foundation as incompatible with
4488-400: Was released under the GPL v2, ending all controversy regarding GPL compatibility. On 28 January 2008 Nokia announced to acquire Trolltech. On 14 January 2009 Qt version 4.5 was relicensed , adding LGPL as licensing option. The Qt Project was founded on 21 October 2011. In August 2012 Digia announced to acquire all rights to Qt and take Nokia's role within the Qt Project. The Qt Project
4556-506: Was resolved when Trolltech released Qt 4.0 also for Windows under the GPL in June 2005. Qt 4 supported the same set of platforms in the free software/open source editions as in the proprietary edition, so it is possible, with Qt 4.0 and later releases, to create GPL-licensed free/open source applications using Qt on all supported platforms. The GPL v3 with special exception was later added as an added licensing option. The GPL exception allows
4624-670: Was the Autonetics D-17 guidance computer for the Minuteman missile , released in 1961. When the Minuteman II went into production in 1966, the D-17 was replaced with a new computer that represented the first high-volume use of integrated circuits. Since these early applications in the 1960s, embedded systems have come down in price and there has been a dramatic rise in processing power and functionality. An early microprocessor,
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