WeatherBug is a brand based in New York City that provides location-based advertising to businesses. WeatherBug consists of a mobile app reporting live and forecast data on hyperlocal weather to consumer users.
116-529: Originally owned by Automated Weather Source, the WeatherBug brand was founded by Bob Marshall and other partners in 1993. It started in the education market by selling weather tracking stations and educational software to public and private schools and then used the data from the stations on their website. Later, the company began partnering with TV stations so that broadcasters could use WeatherBug's local data and camera shots in their weather reports. In 2000,
232-454: A system call or trap . The program uses a library to place data in a well known location in memory and then causes a fault , a type of error. When a system is first started, its kernel is set up to be the "handler" of all faults; thus, when a program causes a fault, the kernel takes over, examines the information passed to it, then carries out the instructions. Under Mach, the IPC system
348-405: A digital zoom shortcut ( iPhone 7 Plus , iOS 10 ). Some camera settings such as video resolution and frame rate are not adjustable through the camera interface itself, but are outsourced to the system settings. A new feature in iOS 13 called "context menus" shows related actions when you touch and hold an item. When the context menu is displayed, the background is blurred. To choose from
464-400: A modal window and could not be viewed after being dismissed. In iOS 5, Apple introduced Notification Center , which allows users to view a history of notifications. The user can tap a notification to open its corresponding app, or clear it. Notifications are now delivered in banners that appear briefly at the top of the screen. If a user taps a received notification, the application that sent
580-557: A Corporation in 2014 from the American Meteorological Society for "developing innovative lightning detection data products that improve severe-storm monitoring and warnings." WeatherBug announced in 2004 it had been certified to display the TRUSTe privacy seal on its website. In 2005, Microsoft AntiSpyware flagged the application as a low-risk spyware threat. According to the company, the desktop application
696-516: A POE Server, resulting in a kernel that was actually larger than the UNIX it was based on. The idea, however, was to move the UNIX layer out of the kernel into user-space, where it could be more easily worked on and even replaced outright. Unfortunately performance proved to be a major problem, and a number of architectural changes were made in order to solve this problem. Unwieldy UNIX licensing issues also plagued researchers, so this early effort to provide
812-454: A basic human right. Building into the core of our products supports a vision of an inclusive world where opportunity and access to information are barrier-free, empowering individuals with disabilities to achieve their goals". Criticism has been aimed at iOS depending on both internet connection (either WiFi or through iTunes) and a working SIM card upon first activation. This restriction has been loosened in iOS 12, which no longer requires
928-403: A dock at the bottom where users can pin their most frequently used apps. iOS home screens are typically made up of app icons and widgets ; app icons launch the associated app, whereas widgets display live, auto-updating content, such as a weather forecast , the user's email inbox, or a news ticker directly on the home screen. The home screen appears whenever the user unlocks the device, presses
1044-402: A feature of the basic system, allowing servers to be raised into the kernel space using built-in mechanisms. Mach 4 attempted to address these problems with a more radical set of upgrades. In particular, it was found that program code was typically not writable, so potential hits due to copy-on-write were rare. Thus it made sense to not map the memory between programs for IPC, but instead migrate
1160-468: A few months after the release of iPhone OS 3.2, which brought the feature to all iPhone and iPod Touch models that could run the operating system, with the exception of the iPhone 3G and the iPod touch (2nd generation) due to performance issues with icon animations. iOS 7 introduced a parallax effect on the Home Screen, which shifts the device's wallpaper and icons in response to the movement of
1276-505: A few options, a selection control is used. Selectors can appear anchored at the bottom or in line with the content (called date selectors). Date selectors take on the appearance of any other selection control, but with a column for day, month, and optionally year. Alerts appear in the center of the screen, but there are also alerts that scroll up from the bottom of the screen (called "action panels"). Destructive actions (such as eliminating any element) are colored red. The official font of iOS
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#17328016371351392-428: A few strategies were developed to improve performance. Like its predecessor, Accent, Mach used a single shared-memory mechanism for physically passing the message from one program to another. Physically copying the message would be too slow, so Mach relies on the machine's memory management unit (MMU) to quickly map the data from one program to another. Only if the data is written to would it have to be physically copied,
1508-477: A new solution to the port concept, using the copy-on-write (COW) mechanism provided by the virtual memory system. Instead of copying data between programs, all that was required was to instruct the MMU to provide access to that same memory. This system would implement the interprocess communications (IPC) system with dramatically higher performance. This concept was picked up at Carnegie-Mellon, who adapted Aleph for
1624-425: A non-licensed UNIX-like system environment continued to find use, well into the further development of Mach. The resulting Mach 3 was released in 1990, and generated intense interest. A small team had built Mach and ported it to a number of platforms, including complex multiprocessor systems which were causing serious problems for older-style kernels. This generated considerable interest in the commercial market, where
1740-493: A number of companies were considering changing hardware platforms. If the existing system could be ported to run on Mach, it seemed it would then be easy to change the platform underneath. Mach received a major boost in visibility when the Open Software Foundation (OSF) announced they would be hosting future versions of OSF/1 on Mach 2.5, and were investigating Mach 3 as well. Mach 2.5 was also selected for
1856-867: A press event, announcing the iPhone SDK. The iOS App Store was opened on July 10, 2008, with an initial 500 applications available. This quickly grew to 3,000 in September 2008, 15,000 in January 2009, 50,000 in June 2009, 100,000 in November 2009, 250,000 in August 2010, 650,000 in July 2012, 1 million in October 2013, 2 million in June 2016, and 2.2 million in January 2017. As of March 2016 , 1 million apps are natively compatible with
1972-419: A process called " copy-on-write ". Messages were also checked for validity by the kernel, to avoid bad data crashing one of the many programs making up the system. Ports were deliberately modeled on the UNIX file system concepts. This permits the user to find ports using existing file system navigation concepts, as well as assigning rights and permissions as they would on the file system. Development under such
2088-451: A series of second generation microkernels, which further reduced the complexity of the system and placed almost all functionality in the user space. For instance, the L4 kernel (version 2) includes only seven system calls and uses 12k of memory, whereas Mach 3 includes about 140 functions and uses about 330k of memory. IPC calls under L4 on a 486DX-50 take only 5μs, faster than a UNIX syscall on
2204-422: A single app that looks the same on any iOS device. In addition to defining the iOS interface, UIKit defines the functionality of the application. At first, Apple did not intend to release an SDK to developers, because they did not want third-party apps to be developed for iOS, building web apps instead. However, this technology never entered into common use, this led Apple to change its opinion, so in October 2007
2320-414: A system would be easier. Not only would the code being worked on exist in a traditional program that could be built using existing tools, it could also be started, debugged and killed off using the same tools. With a monokernel a bug in new code would take down the entire machine and require a reboot, whereas under Mach this would require only that the program be restarted. Additionally the user could tailor
2436-417: A traditional syscall, but not by much. The rest, the majority of the actual problem, was due to the kernel performing tasks such as checking the message for port access rights. While it would seem this is an important security concern, in fact, it only makes sense in a UNIX-like system. For instance, a single-user operating system running a cell phone or robot might not need any of these features, and this
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#17328016371352552-406: A user is directed to the home screen, which is the primary navigation and information "hub" on iOS devices, analogous to the desktop found on personal computers. iOS home screens are typically made up of app icons and widgets ; app icons launch the associated app, whereas widgets display live, auto-updating content, such as a weather forecast , the user's email inbox, or a news ticker directly on
2668-434: A user's ears. Additional customization available for Made for iPhone products include battery tracking and adjustable sound settings for different environments. Apple made further efforts for accessibility for the release of iOS 10 in 2016, adding a new pronunciation editor to VoiceOver, adding a Magnifier setting to enlarge objects through the device's camera, software TTY support for deaf people to make phone calls from
2784-456: A user-space Mach system it would take just under 500μs. When Mach was first being seriously used in the 2.x versions, performance was slower than traditional monolithic operating systems, perhaps as much as 25%. This cost was not considered particularly worrying, however, because the system was also offering multi-processor support and easy portability. Many felt this was an expected and acceptable cost to pay. When Mach 3 attempted to move most of
2900-420: Is San Francisco . It is designed for small text readability, and is used throughout the operating system, including third-party apps. The icons are 180x180px in size for iPhones with a larger screen, usually models over 6 inches, including iPhone 11 Pro and iPhone 8 Plus , while they are 120x120px on iPhones with smaller displays. The home screen, rendered by SpringBoard , displays application icons and
3016-616: Is a kernel developed at Carnegie Mellon University by Richard Rashid and Avie Tevanian to support operating system research, primarily distributed and parallel computing . Mach is often considered one of the earliest examples of a microkernel . However, not all versions of Mach are microkernels. Mach's derivatives are the basis of the operating system kernel in GNU Hurd and of Apple 's XNU kernel used in macOS , iOS , iPadOS , tvOS , and watchOS . The project at Carnegie Mellon ran from 1985 to 1994, ending with Mach 3.0, which
3132-404: Is a mobile operating system developed by Apple exclusively for its devices . It was unveiled in January 2007 for the first-generation iPhone , which launched in June 2007. Major versions of iOS are released annually; the current stable version, iOS 18 , was released to the public on September 16, 2024. It is the operating system that powers many of the company's mobile devices, including
3248-616: Is a component of the WeatherBug app that reports where the nearest lightning strike is to the user based on data from the Total Lightning Network (run by WeatherBug's former owner, Earth Networks) and your phone's GPS location. WeatherBug is a mobile application created by WeatherBug for Android and iOS platforms. An iPhone version was available in October 2007, and the Android version was released in November 2008 and 2009. IOS iOS (formerly iPhone OS )
3364-432: Is a major issue for Mach 3 systems. However, the concept of a multi-server operating system is still promising, though it still requires some research. The developers have to be careful to isolate code into modules that do not call from server to server. For instance, the majority of the networking code would be placed in a single server, thereby minimizing IPC for normal networking tasks. Most developers instead stuck with
3480-516: Is a true microkernel . Mach was developed as a replacement for the kernel in the BSD version of Unix , not requiring a new operating system to be designed around it. Mach and its derivatives exist within several commercial operating systems. These include all using the XNU operating system kernel which incorporates an earlier non-microkernel Mach as a major component. The Mach virtual memory management system
3596-609: Is based on macOS . Like macOS, it includes components of the Mach microkernel and FreeBSD . It is a Unix-like operating system. Although some parts of iOS are open source under the Apple Public Source License and other licenses, iOS is proprietary software . In 2005, when Steve Jobs began planning the iPhone , he had a choice to either "shrink the Mac, which would be an epic feat of engineering, or enlarge
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3712-425: Is common in modern systems, Mach was the first system to define tasks and threads in this way. The kernel's job was reduced from essentially being the operating system to running the "utilities" and providing them access to the hardware. The existence of ports and the use of IPC is perhaps the most fundamental difference between Mach and traditional kernels. Under UNIX, calling the kernel consists of an operation named
3828-467: Is completely free, aimed at acquiring specific technical skills on the creation and management of applications for the Apple ecosystem platforms. At the academy there are also issues of business administration (business planning and business management with a focus on digital opportunities) and there is a path dedicated to the design of graphical interfaces . Students have the opportunity to participate in
3944-452: Is exactly the sort of system where Mach's pick-and-choose operating system would be most valuable. Likewise Mach caused problems when memory had been moved by the operating system, another task that only really makes sense if the system has more than one address space. DOS and the early Mac OS have a single large address space shared by all programs, so under these systems the mapping did not provide any benefits. These realizations led to
4060-463: Is not spyware because it is incapable of tracking users' overall Web use or deciphering anything on their hard drive. In early 2011, AWS Convergence Technologies, Inc. (formerly Automated Weather Source) changed its name to Earth Networks, Inc. In April 2013, WeatherBug was the second most popular weather information service on the Internet, behind only The Weather Channel 's Web site, and ahead of
4176-421: Is possible to interact directly, for example by replying to a message directly from it. Notifications are sent in two modes, critical alerts that are displayed on the lock screen and signaled by a distinctive sound and vibration (e.g. emergency alerts or severe weather alerts), accompanied by a warning banner and the app badge icon, and standard alerts which use a default sound and vibration. Both can be found in
4292-409: Is that it is not clear how to find ports. Under UNIX this problem was solved over time as programmers agreed on a number of "well known" locations in the file system to serve various duties. While this same approach worked for Mach's ports as well, under Mach the operating system was assumed to be much more fluid, with ports appearing and disappearing all the time. Without some mechanism to find ports and
4408-479: The NeXTSTEP system and a number of commercial multiprocessor vendors. Mach 3 led to a number of efforts to port other operating systems parts for the microkernel, including IBM 's Workplace OS and several efforts by Apple to build a cross-platform version of the classic Mac OS . Support for running DOS applications in a Mach 3.0 environment was demonstrated by researchers, following on from earlier work running
4524-517: The PERQ workstation and implemented it using copy-on-write. The port was successful, but the resulting Accent kernel was of limited practical use because it did not run existing software. Moreover, Accent was as tightly tied to PERQ as Aleph was to the Eclipse. The major change between these experimental kernels and Mach was the decision to make a version of the existing 4.2BSD kernel re-implemented on
4640-694: The Worldwide Developer Conference , the annual Apple Developer Conference held annually in California in early June. On June 3, 2019, iPadOS , the branded version of iOS for iPad, was announced at the 2019 WWDC; it was launched on September 25, 2019. The iOS user interface is based upon direct manipulation , using multi-touch gestures such as swipe , tap , pinch , and reverse pinch . Interface control elements include sliders, switches, and buttons. Internal accelerometers are used by some applications to respond to shaking
4756-457: The iPad tablet computer. These apps have collectively been downloaded more than 130 billion times. App intelligence firm Sensor Tower estimated that the App Store would reach 5 million apps by 2020. In September 2007, Apple announced the iPod Touch , a redesigned iPod based on the iPhone form factor. On January 27, 2010, Apple introduced their much-anticipated media tablet ,
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4872-446: The iPhone , and is the basis for three other operating systems made by Apple : iPadOS , tvOS , and watchOS . iOS formerly also powered iPads until iPadOS was introduced in 2019, and the iPod Touch line of devices until its discontinuation. iOS is the world's second most widely installed mobile operating system , after Android . As of December 2023, Apple's App Store contains more than 3.8 million iOS mobile apps . iOS
4988-415: The iPhone 4 and its Retina Display , and retained Helvetica as the system font for older iPhone devices on iOS 4. With iOS 7, Apple announced that they would change the system font to Helvetica Neue Light, a decision that sparked criticism for inappropriate usage of a light, thin typeface for low-resolution mobile screens. Apple eventually chose Helvetica Neue instead. The release of iOS 7 also introduced
5104-489: The "Enterprise Track", an in-depth training experience on the entire life cycle of an app, from design to implementation, to security, troubleshooting , data storage and cloud usage. As of 2020, the academy graduated almost a thousand students from all over the world, who have worked on 400 app ideas and have already published about 50 apps on the iOS App Store . In the 2018–2019 academic year, students from more than 30 countries arrived. 35 of these have been selected to attend
5220-633: The "IOS" trademark from Cisco. The Apple Watch smartwatch was announced by Tim Cook on September 9, 2014, being introduced as a product with health and fitness-tracking. It was released on April 24, 2015. It uses watchOS as its operating system; watchOS is based on iOS, with new features created specially for the Apple Watch such as an activity tracking app. In October 2016, Apple opened its first iOS Developer Academy in Naples inside University of Naples Federico II 's new campus. The course
5336-743: The 1990s. The primary remaining widespread uses of the Mach kernel are Apple's macOS and its sibling iOS, which run atop a heavily modified hybrid Open Software Foundation Mach Kernel (OSFMK 7.3) called " XNU " also used in OSF/1. In XNU, the file systems, networking stacks, and process and memory management functions are implemented in the kernel; and file system, networking, and some process and memory management functions are invoked from user mode via ordinary system calls rather than message passing; XNU's Mach messages are used for communication between user-mode processes, and for some requests from user-mode code to
5452-486: The Accent message-passing concepts. Such a kernel would be binary compatible with existing BSD software, making the system immediately available for everyday use while still being a useful experimental platform. Additionally, the new kernel would be designed from the start to support multiple processor architectures, even allowing heterogeneous clusters to be constructed. In order to bring the system up as quickly as possible,
5568-472: The App Store, iTunes Library, iBookstore , Contacts, and Notes. Content is downloadable via Wi-Fi and optional 3G service or synced through the user's computer. AT&T was initially the sole U.S. provider of 3G wireless access for the iPad. In June 2010, Apple rebranded iPhone OS as "iOS". The trademark "IOS" had been used by Cisco for over a decade for its operating system, IOS , used on its routers. To avoid any potential lawsuit, Apple licensed
5684-690: The Apple Developer Program. Over the years, the Apple Store apps surpassed multiple major milestones, including 50,000, 100,000, 250,000, 500,000, 1 million, and 2 million apps. The billionth application was installed on April 24, 2009. App Library automatically categorizes apps into folders based on their function or type and incluses an alphabetical list of all installed apps. For example, it might group all social media apps into one folder and productivity apps into another. Users can quickly find and access apps by using
5800-573: The BSD system were re-written to call into Mach, and a change to 4.3BSD was also made during this process. By 1986 the system was complete to the point of being able to run on its own on the DEC VAX . Although doing little of any practical value, the goal of making a microkernel was realized. This was soon followed by versions on the IBM RT PC and for Sun Microsystems 68030 -based workstations, proving
5916-581: The Document Picker and Document Provider extensions as part of the document interaction controller. This allows apps to open, save, and interact with documents stored in a central location or cloud storage services. With iOS 11, Apple introduced the Files app and the File Provider extension, providing a central location for users to manage and organize their files. Apps can integrate with
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#17328016371356032-511: The Files app to make their documents accessible and editable directly from the Files app. The storage of iOS devices can be expanded through iCloud , the Apple's cloud-based storage solution that provides 5GB of storage for free to all users, while other plans require a paid subscription. iCloud Drive allows users to store various types of files, such as documents, presentations, and spreadsheets, in
6148-578: The Home screen is granted. In iPhone OS 3, Spotlight was introduced, allowing users to search media, apps, emails, contacts, messages, reminders, calendar events, and similar content. In iOS 7 and later, Spotlight is accessed by pulling down anywhere on the home screen (except for the top and bottom edges that open Notification Center and Control Center). In iOS 9, there are two ways to access Spotlight. As with iOS 7 and 8, pulling down on any homescreen will show Spotlight. However, it can also be accessed as it
6264-598: The Mach kernel would also have to be reentrant, in practice this is not an issue because its response times are so fast it can simply wait and serve requests in turn. Mach also included a server that could forward messages not just between programs, but even over the network, which was an area of intense development in the late 1980s and early 1990s. Unfortunately, the use of IPC for almost all tasks turned out to have serious performance impact. Benchmarks on 1997 hardware showed that Mach 3.0-based UNIX single-server implementations were about 50% slower than native UNIX. Study of
6380-493: The Notification Center, and show for a set amount of time on the lock screen (unless the user has Notification Center allowed when locked). On iPhones with Touch ID, screenshots can be created with the simultaneous press of the home and power buttons. In comparison to Android , which requires the buttons to be held down, a short press does suffice on iOS. On iPhone with Face ID, screenshots are captured using
6496-455: The SDK for developers was announced, finally released on March 6, 2008. The SDK includes an inclusive set of development tools, including an audio mixer and an iPhone simulator. It is a free download for Mac users. It is not available for Microsoft Windows PCs. To test the application, get technical support, and distribute applications through App Store , developers are required to subscribe to
6612-543: The Settings. It is possible to manage brightness, volume, wireless connections, music player, etc. Scrolling from the top left to the bottom (or top to bottom on iPhones with Touch ID) will open the Notification Center , which in the latest versions of iOS is very similar to the lock screen. It displays notifications in chronological order and groups them by application. From the notifications of some apps it
6728-691: The WeatherBug desktop application and website were launched. Later, the company launched WeatherBug and WeatherBug Elite as smartphone apps for iOS and Android , which won an APPY app design award in 2013. The company also sells a lightning tracking safety system that is used by schools and parks in southern Florida and elsewhere. The company used lightning detection sensors throughout Guinea in Africa to track storms as they develop and has more than 50 lightning detection sensors in Brazil . Earth Networks received The Award for Outstanding Services to Meteorology by
6844-409: The ability to scale text or apply other forms of text accessibility changes through Settings. With iOS 9, Apple changed the font to San Francisco , an Apple-designed font aimed at maximum legibility and font consistency across its product lineup. iOS 4 introduced folders, which can be created by dragging an application on top of another, and from then on, more items can be added to the folder using
6960-451: The ability to use custom prompts for encouraging users to leave reviews for their apps. IOS applications can also be installed directly from an IPA file provided by the software distributor, via unofficial ways. They are written using iOS Software Development Kit (SDK) and, often, combined with Xcode , using officially supported programming languages, including Swift and Objective-C . Other companies have also created tools that allow for
7076-582: The app clears the badge. iOS devices come with preinstalled apps developed by Apple including Mail, Maps, TV, Music, FaceTime, Wallet, Health, and many more. Applications (" apps ") are the most general form of application software that can be installed on iOS. They are downloaded from the official catalog of the App Store digital store, where apps are subjected to security checks before being made available to users. In June 2017, Apple updated its guidelines to specify that app developers will no longer have
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#17328016371357192-492: The background can perform to a limited function set and requires application developers to add explicit support for it. Before iOS 4, multitasking was limited to a selection of the applications Apple included on the device. Users could however " jailbreak " their device in order to unofficially multitask. Starting with iOS 4, on third-generation and newer iOS devices, multitasking is supported through seven background APIs : Mach (kernel) Mach ( / m ɑː k / )
7308-498: The basic system was sound, and went on to demonstrate computer clustering by copying the memory over an early Ethernet interface. Around this time a new generation of central processors (CPUs) were coming to market, offering a 32-bit address space and (initially optional) support for a memory management unit (MMU). The MMU handled the instructions needed to implement a virtual memory system by keeping track of which pages of memory were in use by various programs. This offered
7424-464: The caller has required access rights and that the message is valid. If it is, there is another context switch and memory mapping to complete the call into the user-space server. The process must then be repeated to return the results, adding up to a total of four context switches and memory mappings, plus two message verifications. This overhead rapidly compounds with more complex services, where there are often code paths passing through many servers. This
7540-493: The classic Mac OS and MultiFinder under Mach 2.5. Mach was originally intended to be a replacement for classical monolithic UNIX, and for this reason contained many UNIX-like ideas. For instance, Mach provided a permissions and security system similar to that used by UNIX's file system. Since the kernel was privileged (running in kernel-space ) over other OS servers and software, it was possible for malfunctioning or malicious programs to send it commands that would cause damage to
7656-411: The cloud. These files can be accessed across multiple devices as long as the user is signed in with the same Apple ID. iOS offers various accessibility features to help users with vision and hearing disabilities. One major feature, VoiceOver , provides a voice reading information on the screen, including contextual buttons, icons, links and other user interface elements, and allows the user to navigate
7772-499: The development of native iOS apps using their respective programming languages. Applications for iOS are mostly built using components of UIKit , a programming framework. It allows applications to have a consistent look and feel with the OS, nevertheless offering customization. Elements automatically update along with iOS updates, automatically including new interface rules. UIKit elements are very adaptable, this allows developers to design
7888-464: The device (one common result is the undo command) or rotating it in three dimensions (one common result is switching between portrait and landscape mode). Various accessibility described in § Accessibility functions enable users with vision and hearing disabilities to properly use iOS. iOS devices boot to the lock screen. The lock screen shows the time and a user's lock screen widgets, which display timely information from apps. Upon unlock,
8004-419: The device, creating a 3D effect and an illusion of floating icons. This effect is also visible in the tab view of Mail and Safari. Researchers found that users organize icons on their homescreens based on usage frequency and relatedness of the applications, as well as for reasons of usability and aesthetics. iOS originally used Helvetica as the system font. Apple switched to Helvetica Neue exclusively for
8120-399: The drivers out of the microkernel. The main difference with UNIX is that instead of utilities handling files, they can handle any "task". More operating system code was moved out of the kernel and into user space, resulting in a much smaller kernel and the rise of the term microkernel . Unlike traditional systems, under Mach a process, or "task", can consist of a number of threads. While this
8236-411: The entire task, or alternately, used files to pass data, which was resource expensive and time-consuming. Pipes were built on the underlying input/output system. This system is, in turn, based on a model where drivers are expected to periodically "block" while they wait for tasks to complete. For instance, a printer driver might send a line of text to a line printer and then have nothing to do until
8352-400: The exact nature of the performance problems turned up a number of interesting facts. One was that the IPC was not the problem: there was some overhead associated with the memory mapping needed to support it, but this added only a small amount of time to making a call. The rest, 80% of the time being spent, was due to additional tasks the kernel was running on the messages. Primary among these was
8468-491: The expensive IPC needed to call it in. Other performance problems were related to Mach's support for multiprocessor systems. From the mid-1980s to the early 1990s, commodity CPUs grew in performance at a rate of about 60% a year, but the speed of memory access grew at only 7% a year. This meant that the cost of accessing memory grew tremendously over this period, and since Mach was based on mapping memory around between programs, any "cache miss" made IPC calls slow. IPC overhead
8584-457: The folders with pages similar to the home screen layout, allowing for a significant expansion of folder functionality. Each page of a folder can contain up to nine apps, and there can be 15 pages in total, allowing for a total of 135 apps in a single folder. In iOS 9, Apple updated folder sizes for iPad hardware, allowing for 16 apps per page, still at 15 pages maximum, increasing the total to 240 apps. Before iOS 5, notifications were delivered in
8700-439: The hardware, including memory and the ports, while conventional programs using the ports system implemented all behavior, from device drivers to user programs. This concept greatly reduced the size of the kernel, and permitted users to experiment with different drivers simply by loading them and connecting them together at runtime. This greatly eased the problems when developing new operating system code, which would otherwise require
8816-420: The home screen. Along the top of the screen is a status bar, showing information about the device and its connectivity. The Control Center can be "pulled" down from the top right of the notch or Dynamic Island (on iPhones with Face ID ) or can be "pulled" up from the bottom to top of the screen (on iPhones with Touch ID ), giving access to various toggles to manage the device more quickly without having to open
8932-439: The iPad, featuring a larger screen than the iPhone and iPod Touch, and designed for web browsing, media consumption, and reading, and offering multi-touch interaction with multimedia formats including newspapers, e-books, photos, videos, music, word processing documents, video games, and most existing iPhone apps using a 9.7-inch (25 cm) screen. It also includes a mobile version of Safari for web browsing, as well as access to
9048-538: The iPhone with minimal retraining. Forstall was also responsible for creating a software development kit for programmers to build iPhone apps, as well as an App Store within iTunes . The operating system was unveiled with the iPhone at the Macworld Conference & Expo on January 9, 2007, and released in June of that year. At the time of its unveiling in January, Steve Jobs claimed: "iPhone runs OS X" and runs "desktop class applications", but at
9164-550: The iPhone, and giving tutorials and guidelines for third-party developers to incorporate proper accessibility functions into their apps. In 2012, Liat Kornowski from The Atlantic wrote that "the iPhone has turned out to be one of the most revolutionary developments since the invention of Braille ", and in 2016, Steven Aquino of TechCrunch described Apple as "leading the way in assistive technology", with Sarah Herrlinger, Senior Manager for Global Accessibility Policy and Initiatives at Apple, stating that "We see accessibility as
9280-505: The iPod". Jobs favored the former approach but pitted the Macintosh and iPod teams, led by Scott Forstall and Tony Fadell , respectively, against each other in an internal competition, with Forstall winning by creating iPhone OS. The decision enabled the success of the iPhone as a platform for third-party developers: using a well-known desktop operating system as its basis allowed the many third-party Mac developers to write software for
9396-457: The kernel and from the kernel to user-mode servers. Further analysis demonstrated that the IPC performance problem was not as obvious as it seemed. Recall that a single-side of a syscall took 20μs under BSD and 114μs on Mach running on the same system. Of the 114, 11 were due to the context switch, identical to BSD. An additional 18 were used by the MMU to map the message between user-space and kernel space. This adds up to only 29μs, longer than
9512-406: The latter. Multitasking for iOS was first released in June 2010 along with the release of iOS 4 . Only certain devices— iPhone 4 , iPhone 3GS , and iPod Touch 3rd generation—were able to multitask. The iPad did not get multitasking until iOS 4.2.1 in that November. The implementation of multitasking in iOS has been criticized for its approach, which limits the work that applications in
9628-416: The machine to be restarted. The overall concept of a small kernel and external drivers became known as a microkernel. Aleph was implemented on Data General Eclipse minicomputers and was tightly bound to them. This machine was far from ideal, since it required memory to be copied between programs, which resulted in considerable performance overhead. It was also quite expensive. Nevertheless, Aleph proved that
9744-433: The notification will be opened. Users can also choose to view notifications in modal alert windows by adjusting the application's notification settings. Introduced with iOS 8, widgets are now accessible through the Notification Center, defined by 3rd parties. When an app sends a notification while closed, a red badge appears on its icon. This badge tells the user, at a glance, how many notifications that app has sent. Opening
9860-413: The operating system into user-space, the overhead became higher still: benchmarks between Mach and Ultrix on a MIPS R3000 showed a performance hit as great as 67% on some workloads. For example, getting the system time involves an IPC call to the user-space server maintaining system clock . The caller first traps into the kernel, causing a context switch and memory mapping. The kernel then checks that
9976-468: The operating system only, in order to permit user space programs to handle things such as controlling hardware. Under Mach, and like UNIX, the operating system again becomes primarily a collection of utilities. As with UNIX, Mach keeps the concept of a driver for handling the hardware. Therefore, all the drivers for the present hardware have to be included in the microkernel. Other architectures based on hardware abstraction layer or exokernels could move
10092-529: The operating system through gestures. Any apps with default controls and developed with a UIKit framework gets VoiceOver functionality built in. One example includes holding up the iPhone to take a photo, with VoiceOver describing the photo scenery. As part of a "Made for iPhone" program, introduced with the release of iOS 7 in 2013, Apple has developed technology to use Bluetooth and a special technology protocol to let compatible third-party equipment connect with iPhones and iPads for streaming audio directly to
10208-599: The original POE concept of a single large server providing the operating system functionality. In order to ease development, they allowed the operating system server to run either in user-space or kernel-space. This allowed them to develop in user-space and have all the advantages of the original Mach idea, and then move the debugged server into kernel-space in order to get better performance. Several operating systems have since been constructed using this method, known as co-location , among them Lites , MkLinux , OSF/1 , and NeXTSTEP/OPENSTEP/macOS. The Chorus microkernel made this
10324-407: The original Unix operating system is the idea of a pipe . A pipe is an abstraction allowing data to be moved as an unstructured stream of bytes between programs. Using pipes, users can link together multiple programs to complete tasks, feeding data through several consecutive small programs. This contrasts with typical operating systems of the era, which require a single large program that can handle
10440-462: The physical "Home" button while in an app, or swipes up from the bottom of the screen using the home bar. The screen has a status bar across the top to display data, such as time, battery level, and signal strength. The rest of the screen is devoted to the current application. When a passcode is set and a user switches on the device, the passcode must be entered at the Lock Screen before access to
10556-404: The pipe again. In contrast to a file, where the entire file has to be read or written before the next program can use it, pipes made the movement of data across multiple programs occur in a piecemeal fashion without any programmer intervention. However, implementing pipes in memory buffers forced data to be copied from program to program, a time-consuming and resource intensive operation. This made
10672-735: The pipe concept unsuitable for tasks where quick turnaround or low latency was needed, such as in most device drivers . The operating system's kernel and most core functionality was instead written in a single large program. When new functionality, such as computer networking , was added to the operating system, the size and complexity of the kernel grew, too. Unix pipes offered a conceptual system that could be used to build arbitrarily complex solutions out of small cooperating programs. These smaller programs were easier to develop and maintain, and had well-defined interfaces that simplified programming and debugging. These qualities are even more valuable for device drivers, where small size and bug-free performance
10788-417: The port rights checking and message validity. In benchmarks on an 486 DX-50, a standard UNIX system call took an average of 21 μs to complete, while the equivalent operation with Mach IPC averaged 114μs. Only 18μs of this was hardware related; the rest was the Mach kernel running various routines on the message. Given a syscall that does nothing, a full round-trip under BSD would require about 40μs, whereas on
10904-415: The printer completes printing that line. In this case, the driver indicates that it was blocked, and the operating system allows some other program to run until the printer indicates it is ready for more data. In the pipes system the limited resource was memory, and when one program filled the memory assigned to the pipe, it would naturally block. Normally this would cause the consuming program to run, emptying
11020-477: The program code being used into the local space of the program. This led to the concept of "shuttles" and it seemed performance had improved, but the developers moved on with the system in a semi-usable state. Mach 4 also introduced built-in co-location primitives, making it a part of the kernel. By the mid-1990s, work on microkernel systems was largely stagnant, although the market had generally believed that all modern operating systems would be microkernel based by
11136-515: The same procedure. A title for the folder is automatically selected by the category of applications inside, but the name can also be edited by the user. When apps inside folders receive notification badges, the individual numbers of notifications are added up and the total number is displayed as a notification badge on the folder itself. Originally, folders on an iPhone could include up to 12 apps, while folders on iPad could include 20. With increasing display sizes on newer iPhone hardware, iOS 7 updated
11252-414: The same system, and over 20 times as fast as Mach. Of course this ignores the fact that L4 is not handling permissioning or security; but by leaving this to the user-space programs, they can select as much or as little overhead as they require. The potential performance gains of L4 are tempered by the fact that the user-space applications will often have to provide many of the functions formerly supported by
11368-627: The search bar at the top of the App Library. Users can choose to hide specific app pages from the home screen, making it easier to focus on the apps they use most frequently. iOS enforces strict sandboxing to maintain security and privacy. Apps are generally limited to accessing their own containers and specific system-provided directories, such as the Photos library. To access files outside of their sandbox, iOS uses mechanisms like document pickers, file providers, and app extensions. iOS 8 introduced
11484-479: The services they represented, much of this flexibility would be lost. Mach was initially hosted as additional code written directly into the existing 4.2BSD kernel, allowing the team to work on the system long before it was complete. Work started with the already functional Accent IPC/port system, and moved on to the other key portions of the OS: tasks, threads, and virtual memory. As portions were completed various parts of
11600-404: The sites run by Weather Underground and AccuWeather . In November 2016, it was announced that xAd acquired WeatherBug from Earth Networks. In June 2017, xAd rebranded as GroundTruth to reflect a change in company focus from advertising to media and data services. The company developed WeatherBug , a mobile application of their service for Android, iOS and Windows Phone platforms. Spark
11716-563: The system to be distributed over multiple processors, either by using shared memory directly as in most Mach messages, or by adding code to copy the message to another processor if needed. In a traditional kernel this is difficult to implement; the system has to be sure that different programs do not try to write to the same region of memory from different processors. However, using Mach ports makes this well defined and easy to implement, so Mach ports were made first-class citizens in that system. The IPC system initially had performance problems, so
11832-435: The system to include, or exclude, whatever features they required. Since the operating system was simply a collection of programs, they could add or remove parts by simply running or killing them as they would any other program. Finally, under Mach, all of these features were deliberately designed to be extremely platform neutral. To quote one text on Mach: There are a number of disadvantages, however. A relatively mundane one
11948-416: The system would be implemented by starting with the existing BSD code, and gradually re-implementing it as inter-process communication -based (IPC-based) programs. Thus Mach would begin as a monolithic system similar to existing UNIX systems, and progress toward the microkernel concept over time. Mach started largely being an effort to produce a clearly defined, UNIX-based, highly portable Accent. The result
12064-480: The system's portability. By 1987 the list included the Encore Multimax and Sequent Balance machines, testing Mach's ability to run on multiprocessor systems. A public Release 1 was made that year, and Release 2 followed the next year. Throughout this time the promise of a "true" microkernel had not yet been delivered. These early Mach versions included the majority of 4.3BSD in the kernel, a system known as
12180-417: The system, and for this reason the kernel checked every message for validity. Additionally most of the operating system functionality was to be located in user-space programs, so this meant there needed to be some way for the kernel to grant these programs additional privileges, e.g. to directly access hardware. Some of Mach's more esoteric features were also based on this same IPC mechanism. For instance, Mach
12296-607: The time of the iPhone's release, the operating system was renamed "iPhone OS". Initially, third-party native applications were not supported. Jobs' reasoning was that developers could build web applications through the Safari web browser that "would behave like native apps on the iPhone". In October 2007, Apple announced that a native software development kit (SDK) was under development and that they planned to put it "in developers' hands in February". On March 6, 2008, Apple held
12412-558: The volume-up and power buttons instead. The camera application used a skeuomorphic closing camera shutter animation prior to iOS 7. Since then, it uses a simple short blackout effect. Notable additions over time include HDR photography and the option to save both normal and high dynamic range photographs simultaneously where the former prevents ghosting effects from moving objects (since iPhone 5 on iOS 6 ), automatic HDR adjustment (since iOS 7.1 ), "live photo" with short video bundled to each photo if enabled ( iPhone 6s , iOS 9 ), and
12528-518: The word "muck" could form a backronym for their Multi-User (or Multiprocessor Universal) Communication Kernel. Italian CMU engineer Dario Giuse later asked project leader Rick Rashid about the project's current title and received "MUCK" as the answer, though not spelled out but just pronounced IPA: [mʌk] . According to the Italian alphabet , he wrote "Mach". Rashid liked Giuse's spelling "Mach" so much that it prevailed. A key concept in
12644-509: Was a short list of generic concepts: Mach developed on Accent's IPC concepts, but made the system much more UNIX-like in nature, making it possible to run UNIX programs with little or no modification. To do this, Mach introduced the port, representing each endpoint of a two-way IPC. Ports had a concept of permissions like files under UNIX, permitting a very UNIX-like model of protection to be applied to them. Additionally, Mach allowed any program to handle privileges that would normally be given to
12760-404: Was able to support multi-processor machines with ease. In a traditional kernel extensive work needs to be carried out to make it reentrant or interruptible , as programs running on different processors could call into the kernel at the same time. Under Mach, the bits of the operating system are isolated in servers, which are able to run, like any other program, on any processor. Although in theory
12876-649: Was also adopted in 4.4BSD by the BSD developers at CSRG , and appears in modern BSD-derived Unix systems such as FreeBSD . Mach is the logical successor to Carnegie Mellon's Accent kernel . Mach's lead developer Richard Rashid has been employed at Microsoft since 1991; he founded the Microsoft Research division. Co-founding Mach developer Avie Tevanian, was formerly head of software at NeXT , then Chief Software Technology Officer at Apple Inc. until March 2006. The developers rode bicycles to lunch through rainy Pittsburgh's mud puddles, and Tevanian joked
12992-533: Was extremely important. There was a strong desire to model the kernel on the same basis of small cooperating programs. One of the first systems to use a pipe-like system underpinning the operating system was the Aleph kernel developed at the University of Rochester . This introduced the concept of ports, which were essentially a shared memory implementation. In Aleph, the kernel was reduced to providing access to
13108-417: Was in iOS versions 3 through 6. This endows Spotlight with Siri suggestions, which include app suggestions, contact suggestions and news. In iOS 10, Spotlight is at the top of the now-dedicated "Today" panel. With the release of iPhone OS 3.2 , users gained the ability to set a wallpaper for the Home Screen. The feature was initially only available on the iPad (1st generation) until the release of iOS 4
13224-414: Was not possible because the kernel had no real idea what the operating system consisted of. Instead they had to use a single one-size-fits-all solution, which added to the performance problems. Mach 3 attempted to address this problem by providing a simple pager, relying on user-space pagers for better specialization. But this turned out to have little effect. In practice, any benefits it had were wiped out by
13340-412: Was not the only source of performance problems. Another centered on the problems of trying to handle memory properly when physical memory ran low and paging had to occur. In the traditional monolithic operating systems the authors had direct experience with which parts of the kernel called which others, allowing them to fine-tune their pager to avoid paging out code that was about to be used. Under Mach this
13456-640: Was used for this role instead. To call system functionality, a program would ask the kernel for access to a port, then use the IPC system to send messages to that port. Although sending a message requires a system call, just as a request for system functionality on other systems requires a system call, under Mach sending the message is pretty much all the kernel does; handling the actual request would be up to some other program. Thread and concurrency support benefited by message passing with IPC mechanisms since tasks now consist of multiple code threads which Mach could freeze and unfreeze during message handling. This permits
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