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MultiFinder is anextension for theApple Macintosh'sclassic Mac OS, introduced on August 11, 1987[1] and included withSystem Software 5.[2] It addscooperative multitasking of several applications at once – a great improvement over the previous Macintosh systems, which can only run oneapplication at a time. With the advent ofSystem 7, MultiFinder became a standard integrated part of theoperating system and remained so until the introduction ofMac OS X.
The first Macintosh was released in 1984, and Apple's developers made an early decision that the machine's 128KB ofRAM was so limited that they must abandon the application multitasking functionality that Apple had developed for theLisa.[citation needed] As the successive Macintosh hardware models were released with much more RAM being the key feature, new programming techniques were developed as workarounds to allow users to run concurrent applications. Desk Accessories became a staple through the lifespan of System 6; and the Switcher would give way to the MultiFinder, which then became directly integrated into System 7.
To allow some degree of freedom and to deliver the GUI's promise of interface consistency, the original Macintosh includesDesk Accessories, such as a calculator, that can be run concurrently. However, their functionality is deliberately limited in favor ofRAM conservation. In fact, they are device drivers which take advantage of the multitasking system designed for hardware peripheral support. As such, theirrunning environment is severely restricted. They can only draw a single window, which by default is given a special round-bordered appearance. Although the system software does little to specifically support them, the popularity of Desk Accessories led many application developers to ensure good cooperative multitasking support even from the early days.
Andy Hertzfeld, one of Apple's original Macintosh software architects, wrote Switcher after seeingJohn Markoff use aterminate-and-stay-resident program on an IBM PC in October 1984. By the end of the year he had a working prototype, and he soon demonstrated it in public.[3] BothMicrosoft and Apple wanted to purchase the utility. Hertzfeld chose the latter because of his belief that Switcher should be bundled with the Macintosh system. Apple offered more money (US$100,000 plus royalties) and the company planned to ship Switcher with theMacintosh 512K. The first official version of Switcher appeared in April 1985.[4]
Switcher works by designating a number of fixed slots in memory into which applications could be loaded. The user can then switch between these applications by clicking a small button on the top of themenu bar. The current application horizontally slides out of view, and the next one slides in. Though awkward, this approach does fit well with the existing system'smemory management scheme, and applications need no special programming to work with Switcher.[5] This early work on Switcher led to the development of MultiFinder by Apple system software engineers Erich Ringewald andPhil Goldman.
Microsoft saw Switcher as especially benefiting the company's highly memory-optimized Macintosh applications[4] so the utility was shipped withExcel. Microsoft stated that using multiple applications with Switcher was preferable to a singleintegrated software application likeLotus Symphony.[6] By 1987,Compute!'s Apple Applications reported that "many Macintosh owners are comfortable only when using more than one application at a time. Switcher and desk accessories are the two most common examples of that philosophy".[7]PC Magazine said that Switcher used too much of the system's precious little RAM and was not reliable enough.[8]
Multi-Mac is another application switching utility designed specifically for the Macintosh 512K, though it is more known for its mysteriousness. Showing up sometime in late 1985, after the introduction of Switcher, and being credited as being made byJwa van der Vuurst with a copyright byAubrac Systems, it makes over 200 direct calls to undocumented addresses in the Macintosh ROMs.[9] This led to the accusations thatJwa van der Vuurst was merely an alias and that the program was actually from someone that worked at Apple and had significant knowledge on the Macintosh's inner workings. The app itself adds a second apple menu on the right side of the menu bar which displays all currently running application and allows switching between them. It also allows adjusting the applications' memory allocation size, disk cache and adds background multi-threaded copying similar toSpeed Doubler's andMac OS 8's improved copy function.[10]
Servant was another attempt by Andy Hertzfeld at multitasking on the Macintosh, intended to solve Switcher's shortcomings. Released in September 1986, it was effectively a Finder, Switcher andResEdit combined into one tool for theMacintosh Plus.[11] Its file manager is unusual due to its lack of a scrollbar, instead requiring to hold and drag the window background like a modern map app. One of its most interesting features is the first known implementation of wallpapers on the Macintosh, allowing users to replace the default grey background withMacPaint or ThunderScan images.[12] In comparison to Switcher, Servant allows users to open apps as they see fit instead of requiring you to select which apps you want to run first, then launching them inside Switcher. Switcher also has a primitive ability to recover from application crashes as well as force quit stuck applications that are no longer responding.[13] The result is a user experience more intuitive than Switcher. While Servant's resource editing features are not as full featured as ResEdit, it does allow editing file icons.[14]
MultiFinder, known before its release as "Juggler",[15] was introduced on August 11, 1987.[1] It is simply a way for windows from different applications to coexist by using a cooperative application layering model. Its initial release is able to handle only two concurrent applications, one of which runs in the background;[8] and later releases allow many more concurrent applications. When an application is activated, all of its windows are brought forward as a single layer. This approach is necessary forbackward compatibility with many of the windowingdata structures that were already documented. MultiFinder also provides a way for applications to supply their memory requirements ahead of time, so that MultiFinder can allocate a chunk of RAM to each according to need. This scheme, while functional, has severe limitations which cause many problems for users. Virtual memory was only available to contemporary Macs with a PMMU chip (Mac II-class machines required) and an extension named Virtual fromConnectix.[16] Apple eventually provided virtual memory with the introduction of System 7.[17]
Later in 1987, System 6 engineer Erich Ringewald's desire to solve these architectural problems altogether would bring him to defiantly cofound and lead thePink project as the intended future of a new MacOS,[18] and then become chief software architect atBe Inc. to designBeOS in 1990.[19]
With the release ofSystem 7, the MultiFinder extension was integrated with the operating system. However, the integration into the OS does nothing to fix MultiFinder's inherent idiosyncrasies and disadvantages. These problems were not overcome in the mainstream Macintosh operating system until the MultiFinder model was abandoned with the move to a modernpreemptive multitaskingUnix-based OS inMac OS X. Two utilities, CPU Doubler and Peek-A-Boo, did implement a form of priority basedtask scheduling in the classic Mac OS, though they were unable to solve its other issues, like the lack ofprotected memory.[20][21]
Upon MultiFinder's 1987 release,PC Magazine noted it for beatingIBM's competingOS/2 multitasking operating system to market, and said the System with MultiFinder "isn't a true multitasking operating system, though it's much more than a context switcher".[8] Ezra Shapiro ofBYTE in July 1988 recommended MultiFinder to those with "a huge amount of RAM and nerves of steel. I'm always edgy about the devastating crashes that can occur".[22] The magazine'sJerry Pournelle in 1989 said that "while MultiFinder doesn't work very well yet,DESQView on a big 80386 machine certainly does".[23] In 1990,InfoWorld tested the four mainstream desktop multitasking options: DESQView, OS/2 1.2, Windows 3.0, and System 6 with MultiFinder. While stating that its "multitasking capabilities are weak" compared to the other products—"It may be better described as a task switcher than a true multitasker"—MultiFinder was viewed overall positively for speed, compatibility, ease of use, and value. Its presence halved the speed of file transfer and printing compared to the single-tasking System 6 without MultiFinder, but this was still comparable to Windows and DesqView and much faster than OS/2. These tradeoffs were seen as typical of contemporary add-on multitaskers compared to the natively architected but less friendly OS/2.[16]