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128-592: When Apple Computer introduced the Apple II in April 1977, the new computer had no disk drive or disk operating system (DOS). Although Apple co-founder Steve Wozniak designed the Disk II controller late that year, and believed that he could have written a DOS, his co-founder Steve Jobs decided to outsource the task. The company considered using Digital Research 's CP/M , but Wozniak sought an operating system that

256-456: A boardroom coup and called an emergency meeting at which Apple's executive staff sided with Sculley and stripped Jobs of all operational duties. Jobs resigned from Apple in September 1985 and took several Apple employees with him to found NeXT . Wozniak had also quit his active employment at Apple earlier in 1985 to pursue other ventures, expressing his frustration with Apple's treatment of

384-413: A call stack , a special case of the stack data structure , to implement function calls and returns. Each procedure call creates a new entry, called a stack frame , at the top of the stack; when the procedure returns, its stack frame is deleted from the stack, and its space may be used for other procedure calls. Each stack frame contains the private data of the corresponding call, which typically includes

512-611: A multi-touch iPod Nano , an iPod Touch with FaceTime , and an iPod Shuffle that brought back the clickwheel buttons of earlier generations. It also introduced the smaller, cheaper second-generation Apple TV which allowed the rental of movies and shows. On January 17, 2011, Jobs announced in an internal Apple memo that he would take another medical leave of absence for an indefinite period to allow him to focus on his health. Chief operating officer Tim Cook assumed Jobs's day-to-day operations at Apple, although Jobs would still remain "involved in major strategic decisions". Apple became

640-474: A "NIFFUM" utility. There are also commercial utilities (such as Copy II Plus ) that can copy files between either format (and eventually ProDOS as well). Release 3.3 also improves the ability to switch between Integer BASIC and Applesoft BASIC, if the computer has a language card ( RAM expansion) or firmware card. Apple DOS 3.1 disks use 13 sectors of data per track, each sector being 256 bytes . It uses 35 tracks per disk side, and can access only one side of

768-529: A $ 309 million profit. On May 6, 1998, Apple introduced a new all-in-one computer reminiscent of the original Macintosh: the iMac . The iMac was a huge success, with 800,000 units sold in its first five months, and ushered in major shifts in the industry by abandoning legacy technologies like the 3 + 1 ⁄ 2 -inch diskette , being an early adopter of the USB connector, and coming pre-installed with Internet connectivity (the "i" in iMac) via Ethernet and

896-401: A US jury ruled that Samsung should pay Apple $ 1.05 billion (£665m) in damages in an intellectual property lawsuit. Samsung appealed the damages award, which was reduced by $ 450 million and further granted Samsung's request for a new trial. On November 10, 2012, Apple confirmed a global settlement that dismissed all existing lawsuits between Apple and HTC up to that date, in favor of

1024-485: A capability to programming that has commonality. The term used tends to reflect the context in which it is used – usually based on the language being used. For example: The idea of a callable unit was initially conceived by John Mauchly and Kathleen Antonelli during their work on ENIAC and recorded in a January 1947 Harvard symposium on "Preparation of Problems for EDVAC -type Machines." Maurice Wilkes , David Wheeler , and Stanley Gill are generally credited with

1152-485: A decade. In the 1990s, Apple lost considerable market share in the personal computer industry to the lower-priced Wintel duopoly of the Microsoft Windows operating system on Intel -powered PC clones . In 1997, Apple was weeks away from bankruptcy . To resolve its failed operating system strategy, it bought NeXT, effectively bringing Jobs back to the company, who guided Apple back to profitability over

1280-647: A dedicated hardware stack to store return addresses—such hardware supports only a few levels of subroutine nesting, but can support recursive subroutines. Machines before the mid-1960s—such as the UNIVAC I , the PDP-1 , and the IBM 1130 —typically use a calling convention which saved the instruction counter in the first memory location of the called subroutine. This allows arbitrarily deep levels of subroutine nesting but does not support recursive subroutines. The IBM System/360 had

1408-403: A dial-up modem. Its striking teardrop shape and translucent materials were designed by Jonathan Ive , who had been hired by Amelio, and who collaborated with Jobs for more than a decade to reshape Apple's product design. A little more than a year later on July 21, 1999, Apple introduced the iBook consumer laptop. It culminated Jobs's strategy to produce only four products: refined versions of

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1536-417: A different name for a callable unit that returns a value ( function or subprogram ) vs. one that does not ( subroutine or procedure ). Other languages, such as C , C++ , C# and Lisp , use only one name for a callable unit, function . The C-family languages use the keyword void to indicate no return value. If declared to return a value, a call can be embedded in an expression in order to consume

1664-433: A distraction not only for me and my family, but everyone else at Apple as well", and explained that the break would allow the company "to focus on delivering extraordinary products". Though Jobs was absent, Apple recorded its best non-holiday quarter (Q1 FY 2009) during the recession , with revenue of $ 8.16 billion and profit of $ 1.21 billion. After years of speculation and multiple rumored "leaks", Apple unveiled

1792-528: A file one at a time between a disk buffer and main memory, requiring more time and resulting in DOS constantly blowing revs when reading or writing files. Programs became available early on to format disks with modified sector interleaves; these disks give DOS more time between sectors to copy the data, ameliorating the problem. Later, programmers outside Apple rewrote the File Manager routines to avoid making

1920-444: A large screen, tablet-like media device known as the iPad on January 27, 2010. The iPad ran the same touch-based operating system as the iPhone, and all iPhone apps were compatible with the iPad. This gave the iPad a large app catalog on launch, though having very little development time before the release. Later that year on April 3, 2010, the iPad was launched in the U.S. It sold more than 300,000 units on its first day, and 500,000 by

2048-421: A library, in the literal sense, which kept indexed collections of tapes or decks of cards for collective use. To remove the need for self-modifying code , computer designers eventually provided an indirect jump instruction, whose operand, instead of being the return address itself, was the location of a variable or processor register containing the return address. On those computers, instead of modifying

2176-583: A more modern approach. This led to the Pink project in 1988, A/UX that same year, Copland in 1994, and evaluated the purchase of BeOS in 1996. Talks with Be stalled when the CEO, former Apple executive Jean-Louis Gassée , demanded $ 300 million in contrast to Apple's $ 125 million offer. Only weeks away from bankruptcy , Apple's board preferred NeXTSTEP and purchased NeXT in late 1996 for $ 400 million, retaining Steve Jobs . The NeXT acquisition

2304-720: A new high-level format that is suitable for devices of up to 32  MB ; this makes it suitable for hard disks from that era and 3.5-inch floppies . All the Apple computers from the II Plus onward can run both DOS 3.3 and ProDOS, the Plus requiring a "Language Card" memory expansion to use ProDOS; the e and later models have built-in Language Card hardware, and so can run ProDOS straight. ProDOS includes software to copy files from Apple DOS disks. However, many people who had no need for

2432-751: A power struggle between Steve Jobs and CEO John Sculley , who had been hired away from Pepsi two years earlier by Jobs saying, "Do you want to sell sugar water for the rest of your life or come with me and change the world?" Sculley removed Jobs as the head of the Macintosh division, with unanimous support from the Apple board of directors. The board of directors instructed Sculley to contain Jobs and his ability to launch expensive forays into untested products. Rather than submit to Sculley's direction, Jobs attempted to oust him from leadership. Jean-Louis Gassée informed Sculley that Jobs had been attempting to organize

2560-443: A powerful programming tool. The primary purpose is to allow for the decomposition of a large and/or complicated problem into chunks that have relatively low cognitive load and to assign the chunks meaningful names (unless they are anonymous). Judicious application can reduce the cost of developing and maintaining software, while increasing its quality and reliability. Callable units are present at multiple levels of abstraction in

2688-512: A preferential rate. This visit influenced Jobs to implement a GUI in Apple's products, starting with the Apple Lisa . Despite being pioneering as a mass-marketed GUI computer, the Lisa suffered from high costs and limited software options, leading to commercial failure. Jobs, angered by being pushed off the Lisa team, took over the company's Macintosh division. Wozniak and Raskin had envisioned

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2816-530: A renamed issue of version 2.8, was never publicly released due to bugs. Apple published no official documentation until release 3.2. Apple DOS 3.1 was publicly released in June 1978, slightly more than one year after the Apple II was introduced, becoming the first disk-based operating system for any Apple computer. A bug-fix release came later, addressing a problem by means of its MASTER CREATE utility, which

2944-465: A rewrite of the RWTS to make it faster, while allowing for large gains in available floppy disk storage. The newer P5A/P6A PROMs in the disk controller enable the reading and writing of data at a higher density, so 16 sectors (4 KiB) can be stored per track instead of 13 sectors (3.25  KiB ), increasing capacity from 113.75 KB to 140 KB per side – 16 KB of which

3072-456: A sequence of numbers, and so on through the list of subroutines needed for a particular problem. ... All these subroutines will then be stored in the machine, and all one needs to do is make a brief reference to them by number, as they are indicated in the coding. Kay McNulty had worked closely with John Mauchly on the ENIAC team and developed an idea for subroutines for the ENIAC computer she

3200-696: A series of very tiny programs, each of which carries the loading process forward a few steps before passing control to the next program in the chain. The original Apple II included BASIC interpreter in ROM known originally as Apple BASIC and later as Integer BASIC . Variables in this language can only handle integer numbers ranging from −32,768 to +32,767 ( 16-bit binary values); floating point numbers are not supported. Apple commissioned Microsoft to develop Applesoft BASIC , capable of handling floating-point numbers. Applesoft BASIC cannot run Integer BASIC programs, causing some users to resist upgrading to it. DOS 3.3

3328-487: A startup program (usually called HELLO) that is auto-started when this disk is booted from. On top of the File Manager API, the main DOS routines are implemented which hook into the machine's BASIC interpreter and intercept all disk commands. It provides BLOAD , BSAVE , and BRUN for storing, loading, and running binary executables . LOAD , RUN , and SAVE are provided for BASIC programs, and an EXEC

3456-427: A subroutine call instruction that placed the saved instruction counter value into a general-purpose register; this can be used to support arbitrarily deep subroutine nesting and recursive subroutines. The Burroughs B5000 (1961) is one of the first computers to store subroutine return data on a stack. The DEC PDP-6 (1964) is one of the first accumulator-based machines to have a subroutine call instruction that saved

3584-462: A subroutine called MYSUB from the main program. The subroutine would be coded as The JSB instruction placed the address of the NEXT instruction (namely, BB) into the location specified as its operand (namely, MYSUB), and then branched to the NEXT location after that (namely, AA = MYSUB + 1). The subroutine could then return to the main program by executing the indirect jump JMP MYSUB, I which branched to

3712-599: A ten-year license agreement for current and future patents between the two companies. It is predicted that Apple will make US$ 280   million per year from this deal with HTC. In May 2014, Apple confirmed its intent to acquire Dr. Dre and Jimmy Iovine 's audio company Beats Electronics —producer of the "Beats by Dr. Dre" line of headphones and speaker products, and operator of the music streaming service Beats Music —for US$ 3   billion, and to sell their products through Apple's retail outlets and resellers. Iovine believed that Beats had always "belonged" with Apple, as

3840-471: A track in two revolutions with proper interleaving . A sector of the spinning disk passes under the read/write head while the RWTS routine is decoding the just-read sector (or encoding the next one to be written), and if this missed sector is the next one needed, DOS needs to wait nearly an entire revolution of the disk for the sector to come around again. This is called "blowing a rev" and is a well-understood performance bottleneck in disk systems. To avoid this,

3968-533: Is based on NeXTSTEP , OpenStep , and BSD Unix , to combine the stability, reliability, and security of Unix with the ease of use of an overhauled user interface. Second, in May 2001, the first two Apple Store retail locations opened in Virginia and California, offering an improved presentation of the company's products. At the time, many speculated that the stores would fail, but they became highly successful, and

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4096-415: Is most obvious and objectionable in leaf procedures or leaf functions , which return without making any procedure calls themselves. To reduce that overhead, many modern compilers try to delay the use of a call stack until it is really needed. For example, the call of a procedure P may store the return address and parameters of the called procedure in certain processor registers, and transfer control to

4224-418: Is possible, since all the logical characteristics essential to this procedure are available, to evolve a coding instruction for placing the subroutines in the memory at places known to the machine, and in such a way that they may easily be called into use. In other words, one can designate subroutine A as division and subroutine B as complex multiplication and subroutine C as the evaluation of a standard error of

4352-455: Is used by filesystem overhead and a copy of DOS, leaving 124 KB for user programs and data. DOS 3.3 is, however, not backward compatible ; it cannot read or write DOS 3.2 disks. To address this problem, Apple Computer released "MUFFIN", a utility to migrate Apple DOS 3.2 files and programs to version 3.3 disks. Apple never offered a utility to copy in the other direction. To migrate Apple DOS 3.3 files back to version 3.2 disks, someone wrote

4480-401: Is used to declare no return value; for example void in C, C++ and C#. In some languages, such as Python, the difference is whether the body contains a return statement with a value, and a particular callable may return with or without a value based on control flow. In many contexts, a callable may have side effect behavior such as modifying passed or global data, reading from or writing to

4608-438: Is usually implemented as a contiguous area of memory. It is an arbitrary design choice whether the bottom of the stack is the lowest or highest address within this area, so that the stack may grow forwards or backwards in memory; however, many architectures chose the latter. Some designs, notably some Forth implementations, used two separate stacks, one mainly for control information (like return addresses and loop counters) and

4736-398: Is valued at just over $ 3.2 trillion. Apple has received criticism regarding its contractors ' labor practices, its relationship with trade unions , its environmental practices , and its business ethics, including anti-competitive practices and materials sourcing. Nevertheless, the company has a large following and enjoys a high level of brand loyalty . Apple Computer Company

4864-729: The Apple II debuted, the original Apple DOS source code was released by the Computer History Museum on its website. It was donated by the original author, Paul Laughton. Apple Inc. Apple Inc. is an American multinational corporation and technology company headquartered and incorporated in Cupertino, California , in Silicon Valley . It is best known for its consumer electronics , software , and services . Founded in 1976 as Apple Computer Company by Steve Jobs , Steve Wozniak and Ronald Wayne ,

4992-535: The Apple II series was discontinued. It was expensive to produce, and the company decided it was still absorbing sales from lower-cost Macintosh models. After the launch of the LC, Apple encouraged developers to create applications for Macintosh rather than Apple II, and authorized salespersons to redirect consumers from Apple II and toward Macintosh. The Apple IIe was discontinued in 1993. Apple experimented with several other unsuccessful consumer targeted products during

5120-509: The Apple II , became a best seller as one of the first mass-produced microcomputers . Apple introduced the Lisa in 1983 and the Macintosh in 1984, as some of the first computers to use a graphical user interface and a mouse . By 1985, internal company problems led to Jobs leaving to form NeXT, Inc. , and Wozniak withdrawing to other ventures; John Sculley served as long-time CEO for over

5248-518: The Macworld Expo on January 9, 2007, Jobs announced the renaming of Apple Computer, Inc. to Apple Inc., because the company had broadened its focus from computers to consumer electronics. This event also saw the announcement of the iPhone and the Apple TV . The company sold 270,000 first-generation iPhones during the first 30 hours of sales, and the device was called "a game changer for

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5376-534: The Power Macintosh , the first of many computers with Motorola's PowerPC processor. In the wake of the alliance, Apple opened up to the idea of allowing Motorola and other companies to build Macintosh clones . Over the next two years, 75 distinct Macintosh clone models were introduced. However, by 1996, Apple executives were worried that the clones were cannibalizing sales of its own high-end computers, where profit margins were highest. In 1996, Spindler

5504-526: The Power Macintosh G3 desktop and PowerBook G3 laptop for professionals, and the iMac desktop and iBook laptop for consumers. Jobs said the small product line allowed for a greater focus on quality and innovation. Around then, Apple also completed numerous acquisitions to create a portfolio of digital media production software for both professionals and consumers. Apple acquired Macromedia 's Key Grip digital video editing software project which

5632-481: The SoundJam MP audio player software from Casady & Greene . Apple renamed the program iTunes , and simplified the user interface and added CD burning. In 2001, Apple changed course with three announcements. First, on March 24, 2001, Apple announced the release of a new modern operating system, Mac OS X . This was after numerous failed attempts in the early 1990s, and several years of development. Mac OS X

5760-467: The TRS-80 and Commodore PET , because of its character cell-based color graphics and open architecture . The Apple I and early Apple II models use ordinary audio cassette tapes as storage devices, which were superseded by the 5 + 1 ⁄ 4 -inch floppy disk drive and interface called the Disk II in 1978. The Apple II was chosen to be the desktop platform for the first killer application of

5888-654: The chief operating officer . Gassée left the company later that year to set up a rival, Be Inc. The company pivoted strategy and, in October 1990, introduced three lower-cost models: the Macintosh Classic , the Macintosh LC , and the Macintosh IIsi , all of which generated significant sales due to pent-up demand. In 1991, Apple introduced the hugely successful PowerBook with a design that set

6016-524: The execution of a program. Execution continues at the next instruction after the call instruction when it returns control. The features of implementations of callable units evolved over time and varies by context. This section describes features of the various common implementations. Most modern programming languages provide features to define and call functions, including syntax for accessing such features, including: Some languages, such as Pascal , Fortran , Ada and many dialects of BASIC , use

6144-539: The iLife suite. At the Worldwide Developers Conference keynote address on June 6, 2005, Jobs announced that Apple would move away from PowerPC processors, and the Mac would transition to Intel processors in 2006. On January 10, 2006, the new MacBook Pro and iMac became the first Apple computers to use Intel's Core Duo CPU. By August 7, 2006, Apple made the transition to Intel chips for

6272-401: The third- and fourth-generation iPads , which featured Retina displays ; and the iPad Mini , which featured a 7.9-inch screen in contrast to the iPad's 9.7-inch screen. These launches were successful, with the iPhone 5 (released September 21, 2012) becoming Apple's biggest iPhone launch with over two million pre-orders and sales of three million iPads in three days following the launch of

6400-572: The "S" type as data files. A call vector table in the region of $ 03D0–03FF 16 allows programs to find DOS wherever it is loaded in the system memory. For example, if the DOS hooked into the BASIC CLI stops functioning, it can be reinitialized by calling location $ 03D0 16 (976 10 ) – hence the traditional 3D0G ("3D0 go") command to return to BASIC from the System Monitor . The process of loading Apple DOS involves

6528-551: The 1990s, including QuickTake digital cameras , PowerCD portable CD audio players, speakers , the Pippin video game console, the eWorld online service, and Apple Interactive Television Box . Enormous resources were invested in the problematic Newton tablet division, based on John Sculley's unrealistic market forecasts. Throughout this period, Microsoft continued to gain market share with Windows by focusing on delivering software to inexpensive personal computers, while Apple

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6656-535: The App Store could become a billion-dollar business for Apple. By October 2008, Apple was the third-largest mobile handset supplier in the world due to the popularity of the iPhone. On January 14, 2009, Jobs announced in an internal memo that he would be taking a six-month medical leave of absence from Apple until the end of June 2009 and would spend the time focusing on his health. In the email, Jobs stated that "the curiosity over my personal health continues to be

6784-420: The Apple II division and stating that the company had "been going in the wrong direction for the last five years". Wozniak remained employed by Apple as a representative, receiving a stipend estimated to be $ 120,000 per year. Jobs and Wozniak remained Apple shareholders following their departures. After the departures of Jobs and Wozniak in 1985, Sculley launched the Macintosh 512K that year with quadruple

6912-423: The File Manager was built on top of this, and implements functions to open, close, read, write, delete, lock (i.e. write-protect ), unlock (i.e. write-enable), and rename files, and to verify a file's structural integrity. There is also a CATALOG function, for listing files on the diskette, and an INIT function, which formats a disk for use with DOS, storing a copy of DOS on the first three tracks, and storing

7040-497: The IBM System/360 , for example, the branch instructions BAL or BALR, designed for procedure calling, would save the return address in a processor register specified in the instruction, by convention register 14. To return, the subroutine had only to execute an indirect branch instruction (BR) through that register. If the subroutine needed that register for some other purpose (such as calling another subroutine), it would save

7168-421: The Macintosh as a low-cost computer with a text-based interface like the Apple II, but a plane crash in 1981 forced Wozniak to step back from the project. Jobs quickly redefined the Macintosh as a graphical system that would be cheaper than the Lisa, undercutting his former division. Jobs was also hostile to the Apple II division, which at the time, generated most of the company's revenue. In 1984, Apple launched

7296-583: The Macintosh, the first personal computer without a bundled programming language . Its debut was signified by " 1984 ", a US$ 1.5   million television advertisement directed by Ridley Scott that aired during the third quarter of Super Bowl XVIII on January 22, 1984. This was hailed as a watershed event for Apple's success and was called a "masterpiece" by CNN and one of the greatest TV advertisements of all time by TV Guide . The advertisement created great interest in Macintosh , and sales were initially good, but began to taper off dramatically after

7424-656: The RAM, and introduced the LaserWriter , the first reasonably priced PostScript laser printer . PageMaker , an early desktop publishing application taking advantage of the PostScript language, was also released by Aldus Corporation in July 1985. It has been suggested that the combination of Macintosh, LaserWriter, and PageMaker was responsible for the creation of the desktop publishing market. This dominant position in

7552-582: The business world: VisiCalc , a spreadsheet program released in 1979. VisiCalc created a business market for the Apple II and gave home users an additional reason to buy an Apple II: compatibility with the office, but Apple II market share remained behind home computers made by competitors such as Atari , Commodore , and Tandy . On December 12, 1980, Apple (ticker symbol "AAPL") went public selling 4.6 million shares at $ 22 per share ($ .10 per share when adjusting for stock splits as of September 3, 2022 ), generating over $ 100 million, which

7680-546: The call stack mechanism can be viewed as the earliest and simplest method for automatic memory management . However, another advantage of the call stack method is that it allows recursive function calls , since each nested call to the same procedure gets a separate instance of its private data. In a multi-threaded environment, there is generally more than one stack. An environment that fully supports coroutines or lazy evaluation may use data structures other than stacks to store their activation records. One disadvantage of

7808-448: The call stack mechanism is the increased cost of a procedure call and its matching return. The extra cost includes incrementing and decrementing the stack pointer (and, in some architectures, checking for stack overflow ), and accessing the local variables and parameters by frame-relative addresses, instead of absolute addresses. The cost may be realized in increased execution time, or increased processor complexity, or both. This overhead

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7936-439: The callable declares as formal parameters . A caller passes actual parameters , a.k.a. arguments , to match. Different programming languages provide different conventions for passing arguments. In some languages, such as BASIC, a callable has different syntax (i.e. keyword) for a callable that returns a value vs. one that does not. In other languages, the syntax is the same regardless. In some of these languages an extra keyword

8064-444: The company modeled itself after Apple's "unmatched ability to marry culture and technology". The acquisition was the largest purchase in Apple's history. Subroutine In computer programming , a function (also procedure , method , subroutine , routine , or subprogram ) is a callable unit of software logic that has a well-defined interface and behavior and can be invoked multiple times. Callable units provide

8192-407: The company was incorporated by Jobs and Wozniak as Apple Computer, Inc. the following year. It was renamed Apple Inc. in 2007 as the company had expanded its focus from computers to consumer electronics. Apple is the largest technology company by revenue , with US$ 391.04   billion in 2024. The company was founded to produce and market Wozniak's Apple I personal computer. Its second computer,

8320-688: The core of its computer offerings. The next month, in August 1997, Steve Jobs convinced Microsoft to make a $ 150 million investment in Apple and a commitment to continue developing Mac software. This was seen as an "antitrust insurance policy" for Microsoft which had recently settled with the Department of Justice over anti-competitive practices in the United States v. Microsoft Corp. case. Around then, Jobs donated Apple's internal library and archives to Stanford University , to focus more on

8448-428: The current shape for almost all modern laptops. The same year, Apple introduced System 7 , a major upgrade to the Macintosh operating system, adding color to the interface and introducing new networking capabilities. The success of the lower-cost Macs and PowerBook brought increasing revenue. For some time, Apple was doing very well, introducing fresh new products at increasing profits. The magazine MacAddict named

8576-402: The desktop publishing market allowed the company to focus on higher price points, the so-called "high-right policy" named for the position on a chart of price vs. profits. Newer models selling at higher price points offered higher profit margin , and appeared to have no effect on total sales as power users snapped up every increase in speed. Although some worried about pricing themselves out of

8704-505: The desktop publishing market and estranged many of its original consumer customer base who could no longer afford Apple products. The Christmas season of 1989 was the first in the company's history to have declining sales, which led to a 20% drop in Apple's stock price. During this period, the relationship between Sculley and Gassée deteriorated, leading Sculley to effectively demote Gassée in January 1990 by appointing Michael Spindler as

8832-470: The early 1980s, to discover the recalculation dependencies in a spreadsheet. Namely, a location was reserved in each cell to store the return address. Since circular references are not allowed for natural recalculation order, this allows a tree walk without reserving space for a stack in memory, which was very limited on small computers such as the IBM PC . Most modern implementations of a function call use

8960-404: The end of the first week. In May 2010, Apple's market cap exceeded that of competitor Microsoft for the first time since 1989. In June 2010, Apple released the iPhone 4 , which introduced video calling using FaceTime , multitasking , and a new design with an exposed stainless steel frame as the phone's antenna system. Later that year, Apple again refreshed the iPod line by introducing

9088-514: The entire Mac product line—over one year sooner than announced. The Power Mac, iBook, and PowerBook brands were retired during the transition; the Mac Pro , MacBook , and MacBook Pro became their respective successors. Apple also introduced Boot Camp in 2006 to help users install Windows XP or Windows Vista on their Intel Macs alongside Mac OS X. Apple's success during this period was evident in its stock price . Between early 2003 and 2006,

9216-607: The extra copy for most sectors of a file; RWTS was instructed to read or write sectors directly to or from main memory rather than from a disk buffer whenever a full sector was to be transferred. An early patch to provide this functionality was published in Call-A.P.P.L.E. . Speedups in the LOAD command of three to five times were typical. This functionality soon appeared in commercial products, such as Pronto-DOS, Diversi-DOS, Hyper-DOS, and David-DOS, along with additional features, but it

9344-504: The first of more than 500 stores around the world. Third, on October 23, 2001, the iPod portable digital audio player debuted. The product was first sold on November 10, 2001, and was extremely successful, with over 100 million units sold within six years. In 2003, the iTunes Store was introduced with music downloads for 99¢ a song and iPod integration. It quickly became the market leader in online music services, with over 5 billion downloads by June 19, 2008. Two years later,

9472-480: The first prototype Apple I at the Homebrew Computer Club in July 1976. The Apple I was sold as a motherboard with CPU , RAM , and basic textual-video chips—a base kit concept which was not yet marketed as a complete personal computer. It was priced soon after debut for $ 666.66 (equivalent to $ 3,600 in 2023). Wozniak later said he was unaware of the coincidental mark of the beast in

9600-399: The first three months as reviews started to come in. Jobs had required 128 kilobytes of RAM, which limited its speed and software in favor of aspiring for a projected price point of $ 1,000 (equivalent to $ 2,900 in 2023). The Macintosh shipped for $ 2,495 (equivalent to $ 7,300 in 2023), a price panned by critics due to its slow performance. In early 1985, this sales slump triggered

9728-477: The floppy disk, unless the user flipped the disk over . This gives the user a total storage capacity of 113.75 KB per side, of which about 10 KB are used to store DOS itself and the disk directory, leaving about 100 KB for user programs. The first layer of the operating system is called RWTS, which stands for "read/write track sector". This layer consists of subroutines for track seeking, sector reading and writing, and disk formatting. An API called

9856-579: The formal invention of this concept, which they termed a closed sub-routine , contrasted with an open subroutine or macro . However, Alan Turing had discussed subroutines in a paper of 1945 on design proposals for the NPL ACE , going so far as to invent the concept of a return address stack . The idea of a subroutine was worked out after computing machines had already existed for some time. The arithmetic and conditional jump instructions were planned ahead of time and have changed relatively little, but

9984-442: The free sector map, which was restricted to part of a single sector) is such that it is not possible to have more than 400 KB available at a time per drive without a major rewrite of almost all sections of the code; this is the main reason Apple abandoned this iteration of DOS in 1983, when Apple DOS was entirely replaced by ProDOS . ProDOS retains the 16-sector low-level format of DOS 3.3 for 5.25 inch disks, but introduces

10112-422: The function's return jump, the calling program would store the return address in a variable so that when the function completed, it would execute an indirect jump that would direct execution to the location given by the predefined variable. Another advance was the jump to subroutine instruction, which combined the saving of the return address with the calling jump, thereby minimizing overhead significantly. In

10240-458: The iPad Mini and fourth-generation iPad (released November 3, 2012). Apple also released a third-generation 13-inch MacBook Pro with a Retina display and new iMac and Mac Mini computers. On August 20, 2012, Apple's rising stock price increased the company's market capitalization to a then-record $ 624 billion. This beat the non-inflation-adjusted record for market capitalization previously set by Microsoft in 1999. On August 24, 2012,

10368-465: The iTunes Store was the world's largest music retailer. In 2002, Apple purchased Nothing Real for its advanced digital compositing application Shake , and Emagic for the music productivity application Logic . The purchase of Emagic made Apple the first computer manufacturer to own a music software company. The acquisition was followed by the development of Apple's consumer-level GarageBand application. The release of iPhoto that year completed

10496-562: The iTunes Store, effective in May 2007. Other record labels eventually followed suit and Apple published a press release in January 2009 to announce that all songs on the iTunes Store are available without their FairPlay DRM. In July 2008, Apple launched the App Store to sell third-party applications for the iPhone and iPod Touch . Within a month, the store sold 60 million applications and registered an average daily revenue of $ 1 million, with Jobs speculating in August 2008 that

10624-506: The ill-fated Apple III computer and its SOS operating system. Two more versions of Apple DOS, both still called DOS 3.3 but with some bug fixes and better support for the new Apple IIe model, were released in early and mid-1983. Without third-party patches , Apple DOS can only read floppy disks running in a 5.25-inch Disk II drive and cannot access any other media, such as hard disk drives, virtual RAM drives, or 3.5-inch floppy disk drives. The structure of Apple DOS disks (particularly

10752-430: The improvements of ProDOS (and who did not like its much higher memory footprint ) continued using Apple DOS or one of its clones long after 1983. The Apple convention of storing a bootable OS on every single floppy disk means that commercial software can be used no matter what OS the user owns. A program called DOS.MASTER enables users to have multiple virtual DOS 3.3 partitions on a larger ProDOS volume, which allows

10880-432: The incorporation of Apple. During the first five years of operations, revenues grew exponentially, doubling about every four months. Between September 1977 and September 1980, yearly sales grew from $ 775,000 to US$ 118   million, an average annual growth rate of 533%. The Apple II , also designed by Wozniak, was introduced on April 16, 1977, at the first West Coast Computer Faire . It differs from its major rivals,

11008-408: The industry". In an article posted on Apple's website on February 6, 2007, Jobs wrote that Apple would be willing to sell music on the iTunes Store without digital rights management , thereby allowing tracks to be played on third-party players if record labels would agree to drop the technology. On April 2, 2007, Apple and EMI jointly announced the removal of DRM technology from EMI's catalog in

11136-412: The location stored at location MYSUB. Compilers for Fortran and other languages could easily make use of these instructions when available. This approach supported multiple levels of calls; however, since the return address, parameters, and return values of a subroutine were assigned fixed memory locations, it did not allow for recursive calls. Incidentally, a similar method was used by Lotus 1-2-3 , in

11264-487: The market, the high-right policy was in full force by the mid-1980s, due to Jean-Louis Gassée's slogan of "fifty-five or die", referring to the 55% profit margins of the Macintosh II . This policy began to backfire late in the decade as desktop publishing programs appeared on IBM PC compatibles with some of the same functionality of the Macintosh at far lower price points. The company lost its dominant position in

11392-456: The most part since 2011, Apple has been the world's largest company by market capitalization , and, as of 2023 , is the largest manufacturing company by revenue , the fourth-largest personal computer vendor by unit sales , the largest vendor of tablet computers , and the largest vendor of mobile phones in the world. Apple became the first publicly traded U.S. company to be valued at over $ 1 trillion in 2018, and, as of June 2024 ,

11520-418: The most valuable consumer-facing brand in the world. In June 2011, Jobs surprisingly took the stage and unveiled iCloud , an online storage and syncing service for music, photos, files, and software which replaced MobileMe , Apple's previous attempt at content syncing. This would be the last product launch Jobs would attend before his death. On August 24, 2011, Jobs resigned his position as CEO of Apple. He

11648-480: The next decade with the introductions of the iMac , iPod , iPhone , and iPad devices to critical acclaim as well as the iTunes Store , launching the " Think different " advertising campaign, and opening the Apple Store retail chain. These moves elevated Apple to consistently be one of the world's most valuable brands since about 2010. Jobs resigned in 2011 for health reasons, and died two months later; he

11776-486: The number 666, and that he came up with the price because he liked "repeating digits". Apple Computer, Inc. was incorporated in Cupertino, California , on January 3, 1977, without Wayne, who had left and sold his share of the company back to Jobs and Wozniak for $ 800 only twelve days after having co-founded it. Multimillionaire Mike Markkula provided essential business expertise and funding of $ 250,000 (equivalent to $ 1,257,000 in 2023) to Jobs and Wozniak during

11904-496: The other for data. The former was, or worked like, a call stack and was only indirectly accessible to the programmer through other language constructs while the latter was more directly accessible. When stack-based procedure calls were first introduced, an important motivation was to save precious memory. With this scheme, the compiler does not have to reserve separate space in memory for the private data (parameters, return address, and local variables) of each procedure. At any moment,

12032-505: The period between 1989 and 1991 as the "first golden age" of the Macintosh. The success of lower-cost consumer Macs, especially the LC, cannibalized higher-priced machines. To address this, management introduced several new brands, selling largely identical machines at different price points, for different markets: the high-end Quadra series, the mid-range Centris series, and the consumer-marketed Performa series. This led to significant consumer confusion between so many models. In 1993,

12160-451: The present and the future rather than the past. He ended the Mac clone deals and in September 1997, purchased the largest clone maker, Power Computing . On November 10, 1997, the Apple Store website launched, which was tied to a new build-to-order manufacturing model similar to PC manufacturer Dell 's success. The moves paid off for Jobs; at the end of his first year as CEO, the company had

12288-420: The price of Apple's stock increased more than tenfold, from around $ 6 per share ( split-adjusted ) to over $ 80. When Apple surpassed Dell's market cap in January 2006, Jobs sent an email to Apple employees saying Dell's CEO Michael Dell should eat his words. Nine years prior, Dell had said that if he ran Apple he would "shut it down and give the money back to the shareholders". During his keynote speech at

12416-522: The procedure's body by a simple jump. If the procedure P returns without making any other call, the call stack is not used at all. If P needs to call another procedure Q , it will then use the call stack to save the contents of any registers (such as the return address) that will be needed after Q returns. In general, a callable unit is a list of instructions that, starting at the first instruction, executes sequentially except as directed via its internal logic. It can be invoked (called) many times during

12544-408: The procedure's parameters and internal variables, and the return address. The call sequence can be implemented by a sequence of ordinary instructions (an approach still used in reduced instruction set computing (RISC) and very long instruction word (VLIW) architectures), but many traditional machines designed since the late 1960s have included special instructions for that purpose. The call stack

12672-421: The program instructions into memory from a punched paper tape . Each subroutine could then be provided by a separate piece of tape, loaded or spliced before or after the main program (or "mainline" ); and the same subroutine tape could then be used by many different programs. A similar approach was used in computers that loaded program instructions from punched cards . The name subroutine library originally meant

12800-492: The programming environment. For example, a programmer may write a function in source code that is compiled to machine code that implements similar semantics . There is a callable unit in the source code and an associated one in the machine code, but they are different kinds of callable units – with different implications and features. The meaning of each callable term (function, procedure, method, ...) is, in fact, different. They are not synonymous . Nevertheless, they each add

12928-555: The register's contents to a private memory location or a register stack . In systems such as the HP 2100 , the JSB instruction would perform a similar task, except that the return address was stored in the memory location that was the target of the branch. Execution of the procedure would actually begin at the next memory location. In the HP 2100 assembly language, one would write, for example to call

13056-415: The return address in a stack addressed by an accumulator or index register. The later PDP-10 (1966), PDP-11 (1970) and VAX-11 (1976) lines followed suit; this feature also supports both arbitrarily deep subroutine nesting and recursive subroutines. In the very early assemblers, subroutine support was limited. Subroutines were not explicitly separated from each other or from the main program, and indeed

13184-516: The return value. For example, a square root callable unit might be called like y = sqrt(x) . A callable unit that does not return a value is called as a stand-alone statement like print("hello") . This syntax can also be used for a callable unit that returns a value, but the return value will be ignored. Some older languages require a keyword for calls that do not consume a return value, like CALL print("hello") . Most implementations, especially in modern languages, support parameters which

13312-426: The same track. However, the sector 0 actually needed in most cases will be on the next-higher track, and that track can be arranged relative to the last one to allow the needed time to decode the just-read sector and move the head before sector 0 comes around. On average, a full track can be read in two revolutions of the disk. The early DOS File Manager subverted this efficiency by copying bytes read from or written to

13440-459: The sectors on a DOS disk are arranged in an interleaved order: Later, ProDOS arranged the sectors in this order: When reading and decoding sector 0, then sector 8 passes by, so that sector 1, the next sector likely to be needed, will be available without waiting. When reading sector 7, two unneeded sectors, f and 0, pass by before sector 8 is available, and when reading sector 15, the drive will always have to wait an extra revolution for sector 0 on

13568-420: The source code of a subroutine could be interspersed with that of other subprograms. Some assemblers would offer predefined macros to generate the call and return sequences. By the 1960s, assemblers usually had much more sophisticated support for both inline and separately assembled subroutines that could be linked together. One of the first programming languages to support user-written subroutines and functions

13696-634: The special instructions used for procedure calls have changed greatly over the years. The earliest computers and microprocessors, such as the Manchester Baby and the RCA 1802 , did not have a single subroutine call instruction. Subroutines could be implemented, but they required programmers to use the call sequence—a series of instructions—at each call site . Subroutines were implemented in Konrad Zuse 's Z4 in 1945. In 1945, Alan M. Turing used

13824-457: The stack contains only the private data of the calls that are currently active (namely, which have been called but haven't returned yet). Because of the ways in which programs were usually assembled from libraries, it was (and still is) not uncommon to find programs that include thousands of functions, of which only a handful are active at any given moment. For such programs, the call stack mechanism could save significant amounts of memory. Indeed,

13952-462: The successor of the Apple II, the Apple II Plus. New firmware included an auto-start feature which automatically found a disk controller and booted from it when the system was powered up—earning it the name "Autostart ROM ". DOS 3.2.1 was then released in July 1979 with some minor bug fixes. Apple DOS 3.3 was released in 1980. It improves various functions of release 3.2 including

14080-482: The terms "bury" and "unbury" as a means of calling and returning from subroutines. In January 1947 John Mauchly presented general notes at 'A Symposium of Large Scale Digital Calculating Machinery' under the joint sponsorship of Harvard University and the Bureau of Ordnance, United States Navy. Here he discusses serial and parallel operation suggesting ...the structure of the machine need not be complicated one bit. It

14208-432: The use of many floppy-based DOS programs with a hard disk. Shortly after ProDOS came out, Apple withdrew permission from third parties to redistribute DOS 3.3, but granted one company, Syndicomm, an exclusive license to resell DOS 3.3. Commercial games usually did not use Apple DOS, instead having their own custom disk routines for copy protection purposes as well as for performance. DOS's RWTS routine can read or write

14336-446: Was FORTRAN II . The IBM FORTRAN II compiler was released in 1958. ALGOL 58 and other early programming languages also supported procedural programming. Even with this cumbersome approach, subroutines proved very useful. They allowed the use of the same code in many different programs. Memory was a very scarce resource on early computers, and subroutines allowed significant savings in the size of programs. Many early computers loaded

14464-480: Was delivering a richly engineered but expensive experience. Apple relied on high profit margins and never developed a clear response; it sued Microsoft for making a GUI similar to the Lisa in Apple Computer, Inc. v. Microsoft Corp. The lawsuit dragged on for years and was finally dismissed. The major product flops and the rapid loss of market share to Windows sullied Apple's reputation, and in 1993 Sculley

14592-547: Was easier to use. On 10 April 1978 Apple signed a $ 13,000 contract with Shepardson Microsystems to write a DOS and deliver it within 35 days. Apple provided detailed specifications, and early Apple employee Randy Wigginton worked closely with Shepardson's Paul Laughton as the latter wrote the operating system with punched cards and a minicomputer . There was no Apple DOS 1 or 2. Versions 0.1 through 2.8 were serially enumerated revisions during development, which might as well have been called builds 1 through 28. Apple DOS 3.0,

14720-458: Was finalized on February 9, 1997, and the board brought Jobs back to Apple as an advisor. On July 9, 1997, Jobs staged a boardroom coup that resulted in Amelio's resignation after overseeing a three-year record-low stock price and crippling financial losses. The board named Jobs as interim CEO and he immediately reviewed the product lineup. Jobs canceled 70% of models, ending 3,000 jobs and paring to

14848-479: Was founded on April 1, 1976, by Steve Jobs , Steve Wozniak , and Ronald Wayne as a partnership . The company's first product is the Apple I , a computer designed and hand-built entirely by Wozniak. To finance its creation, Jobs sold his Volkswagen Bus , and Wozniak sold his HP-65 calculator. Neither received the full selling price but in total earned $ 1,300 (equivalent to $ 7,000 in 2023). Wozniak debuted

14976-546: Was launched as Final Cut Pro in April 1999. Key Grip's development also led to Apple's release of the consumer video-editing product iMovie in October 1999. Apple acquired the German company Astarte in April 2000, which had developed the DVD authoring software DVDirector, which Apple repackaged as the professional-oriented DVD Studio Pro , and reused its technology to create iDVD for the consumer market. In 2000, Apple purchased

15104-582: Was more capital than any IPO since Ford Motor Company in 1956. By the end of the day, around 300 millionaires were created, including Jobs and Wozniak, from a stock price of $ 29 per share and a market cap of $ 1.778 billion. In December 1979, Steve Jobs and Apple employees, including Jef Raskin , visited Xerox PARC , where they observed the Xerox Alto , featuring a graphical user interface (GUI). Apple subsequently negotiated access to PARC's technology, leading to Apple's option to buy shares at

15232-416: Was never used in an official Apple DOS release. Similar functionality was, however, employed by Apple's successor operating system, ProDOS. The Apple IIGS -specific operating system GS/OS would eventually employ an even more efficient "scatter read" technique that would read any sector that happened to be passing under the read head if it was needed for the file being read. In 2013, more than 35 years after

15360-500: Was on January 19, 2012, when Apple's Phil Schiller introduced iBooks Textbooks for iOS and iBook Author for Mac OS X in New York City. Jobs stated in the biography Steve Jobs that he wanted to reinvent the textbook industry and education. From 2011 to 2012, Apple released the iPhone 4s and iPhone 5 , which featured improved cameras, an intelligent software assistant named Siri , and cloud-synced data with iCloud;

15488-529: Was programming during World War II. She and the other ENIAC programmers used the subroutines to help calculate missile trajectories. Goldstine and von Neumann wrote a paper dated 16 August 1948 discussing the use of subroutines. Some very early computers and microprocessors, such as the IBM 1620 , the Intel 4004 and Intel 8008 , and the PIC microcontrollers , have a single-instruction subroutine call that uses

15616-496: Was provided for running text-based batch files consisting of BASIC and DOS commands. Finally, four types of files exist, identified by letters in a catalog listing: There are four additional file types; "R", "S", and an additional "A" and "B", none of which are fully supported. DOS recognizes these types for catalog listings only, and there are no direct ways to manipulate these types of files. The "R" type found some use for relocatable binary executable files. A few programs support

15744-432: Was released when Applesoft BASIC was standard in ROM on the Apple II Plus, so Apple designed it to support switching back and forth between the two BASIC interpreters. Integer BASIC is loaded into RAM on the language card of Apple IIs (if present) and by typing FP or INT from BASIC, the user can switch between either version. After 1980, Apple DOS entered into a state of stagnation as Apple concentrated its efforts on

15872-581: Was replaced as CEO by Gil Amelio , who was hired for his reputation as a corporate rehabilitator. Amelio made deep changes, including extensive layoffs and cost-cutting. This period was also marked by numerous failed attempts to modernize the Macintosh operating system (MacOS). The original Macintosh operating system ( System 1 ) was not built for multitasking (running several applications at once). The company attempted to correct this by introducing cooperative multitasking in System 5, but still decided it needed

16000-607: Was replaced as CEO by Michael Spindler . Under Spindler, Apple, IBM , and Motorola formed the AIM alliance in 1994 to create a new computing platform (the PowerPC Reference Platform or PReP), with IBM and Motorola hardware coupled with Apple software. The AIM alliance hoped that PReP's performance and Apple's software would leave the PC far behind and thus counter the dominance of Windows. That year, Apple introduced

16128-472: Was replaced by Cook and Jobs became Apple's chairman. Apple did not have a chairman at the time and instead had two co-lead directors— Andrea Jung and Arthur D. Levinson —who continued with those titles until Levinson replaced Jobs as chairman of the board in November after Jobs's death. On October 5, 2011, Steve Jobs died, marking the end of an era for Apple. The next major product announcement by Apple

16256-517: Was succeeded as CEO by Tim Cook . Apple's current product lineup includes portable and home hardware such as the iPhone, iPad, Apple Watch , Mac , and Apple TV ; operating systems such as iOS , iPadOS , and macOS ; and various software and services including Apple Pay , iCloud , and multimedia streaming services like Apple Music and Apple TV+ . Apple is one of the Big Five American information technology companies; for

16384-476: Was used to create Apple DOS master (bootable) disks: The built-in INIT command created disks that could be booted only on machines with at least the same amount of memory as the one that had created them. MASTER CREATE includes a self-relocating version of DOS that boots on Apples with any memory configuration. Apple DOS 3.2 was released in 1979 to reflect changes in computer booting methods that were built into

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