MultiFinder was the name of a piece of extension software for the Apple Macintosh, introduced in System Software 5 in 1988 and included with System Software 6. On the Apple Macintosh operating system prior to Mac OS X, extensions were small pieces of code that extended the system's functionality Macintosh, commonly nicknamed Mac is a Brand name which covers several lines of Personal computers designed developed and marketed by Apple Inc System 6 (also referred to as System Software 6) is a Graphical user interface -based Operating system for Macintosh computers It added the ability to co-operatively multitask between several applications at once – a great improvement over the previous systems, which could only run one application at a time. In computing Multitasking is a method by which multiple tasks also known as processes, share common processing resources such as a CPU. Application software is a subclass of Computer software that employs the capabilities of a computer directly and thoroughly to a task that the user wishes to perform With the advent of System 7, MultiFinder became a standard integrated part of the operating system. System 7 (codenamed "Big Bang" and sometimes called Mac OS 7) is a single-user Graphical user interface -based Operating system for Macintosh An operating system (commonly abbreviated OS and O/S) is the software component of a Computer system that is responsible for the management and coordination It remained a part of the operating system until Mac OS X. Mac OS X (mæk oʊ ɛs tɛn is a line of computer Operating systems developed marketed and sold by Apple Inc, the latest of which is pre-loaded on all currently
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History before the MultiFinder
The first Macintosh, released in 1984, had such limited memory (128KB) that Apple's developers decided early on to abandon the multi-tasking that Apple had developed for the Lisa. For the MOS 6502 assembler for Apple II computers see Lisa assembler.
Desktop Accessories
To allow some degree of freedom, the original Macintosh included Desk Accessories, such as a calculator, that could be run concurrently. In the operating system for the Apple Macintosh computer a Desk Accessory (DA was a piece of Software, originally written as a device driver conforming However, these were deliberately limited so that they would not use up too much of the available RAM.
Switcher
In 1986, Apple released the Mac Plus which came standard with 1MB of RAM. The Macintosh Plus computer was the third model in the Macintosh line introduced two years after the original Macintosh and a little more than a year after the Macintosh This amount of memory was sufficient to support some form of multitasking, which was first implemented by Andy Hertzfeld in his Switcher program released in April 1985. Andy Hertzfeld (born April 6, 1953) was a key member of the original Apple Macintosh development team Switcher worked by designating a number of fixed "slots" in memory, into which applications could be loaded. The user could then switch between these applications by clicking a small button on the top of the menu bar. A menu bar is a region where computer menus are housed Its purpose is to house window- or application-specific menus which provide access to such functions as opening files The current application would horizontally slide out of view, and the next one would slide in. Despite its awkwardness, this approach did fit well with the existing system's memory management scheme, and applications needed no special programming to work with Switcher. Historically the Mac OS used a form of Memory management that has fallen out of favour in modern systems This early work on Switcher led to the development of MultiFinder by Apple system software engineers Erich Ringewald and Phil Goldman. Phil Goldman ( July 17, 1964 &ndash December 26, 2003) was an American engineer and entrepreneur best known for co-founding WebTV.
MultiFinder
MultiFinder extended the system in a number of significant ways. In addition to giving each application CPU time, it provided a way for windows from different applications to co-exist by using an application layering model. When an application was activated, all of its windows were brought forward as a single layer. This approach was necessary for backward compatibility with many of the windowing data structures that were already documented. In Technology, especially Computing (irrespective of platform a product is said to be backward compatible when it is able to take the place of an older product A data structure in Computer science is a way of storing Data in a computer so that it can be used efficiently It also provided a way for applications to supply their memory requirements ahead of time, so that MultiFinder could allocate a chunk of RAM to each according to need. This scheme, while functional, turned out to have severe limitations which caused many problems for users (see Mac OS memory management for more details). Historically the Mac OS used a form of Memory management that has fallen out of favour in modern systems
With the release of System 7, the MultiFinder extension was integrated with the operating system, and it remained so in Mac OS 8 and Mac OS 9. System 7 (codenamed "Big Bang" and sometimes called Mac OS 7) is a single-user Graphical user interface -based Operating system for Macintosh Mac OS 8 is an Operating system released by Apple Computer on July 26 1997. Mac OS 9 is the final major release of Apple's "Classic" Mac OS. However, the integration into the OS did nothing to fix MultiFinder's inherent idiosyncrasies and disadvantages. These problems were not overcome until MultiFinder was abandoned with the move to a modern preemptive multitasking UNIX-based OS in Mac OS X. Pre-emption or preemption in Computing is the act of temporarily interrupting a task being carried out by a computer system, without requiring Unix (officially trademarked as UNIX, sometimes also written as Unix with Small caps) is a computer Mac OS X (mæk oʊ ɛs tɛn is a line of computer Operating systems developed marketed and sold by Apple Inc, the latest of which is pre-loaded on all currently
External links
- Folklore.org — Andy Hertzfeld himself on how the Switcher idea was born and nearly ended up in the hands of Bill Gates
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