Tuesday, June 30, 2009

Mac OS

Mac OS is the trademarked name for a series of graphical user interface-based operating systems developed by Apple Inc. (formerly Apple Computer, Inc.) for their Macintosh line of computer systems. The Macintosh user experience is credited with popularizing the graphical user interface. The original form of what Apple would later name the "Mac OS" was the integral and unnamed system software first introduced in 1984 with the original Macintosh, usually referred to simply as the System software. It was a trimmed-down version of the operating system underpinning Apple's earlier Lisa product. ed the existence of the operating system in the early years of the Macintosh to help make the machine appear more user-friendly and to distance it from other operating systems such as MS-DOS, which was more arcane and technically challenging. Much of this early system software was held in ROM, with updates typically provided free of charge by Apple dealers on floppy disk. As increasing disk storage capacity and performance gradually eliminated the need for fixing much of an advanced GUI operating system in ROM, Apple explored cloning while positioning major operating system upgrades as separate revenue-generating products, first with System 7 and System 7.5, then with Mac OS 7.6 in 1997

The Mac OS can be divided into two families:

  • The Mac OS Classic family, which was based on Apple's own code
  • The Mac OS X operating system, derived from UNIX.
STAR TREK

One interesting historical aspect of the classic Mac OS was a relatively unknown secret prototype Apple started work on in 1992, code-named "Star Trek" (as in "to boldly go where no Mac has gone before"). The goal of this project was to create a version of Mac OS that would run on Intel-compatible x86 personal computers. The project was instigated by Novell, Inc., who were looking to integrate their DR-DOS with the Mac OS UI as a retort to Microsoft's Windows 3.0. The Apple/Novell team (fourteen engineers from the former, four from the latter) was able to get the Macintosh Finder and some basic applications, like QuickTime, running smoothly on a PC. Some of the code from this effort was reused when porting the Mac OS later to PowerPC.

The project was short lived, being canceled only one year later in early 1993. There are two theories for the cancellation: the first is that Apple's board canceled further development upon realizing that going with Star Trek would mean an entirely new business model and one that would likely see a notable drop in Apple's lucrative hardware sales; and the second is that an x86 Mac OS was not commercially viable in the early nineties because Microsoft's contracts for Windows 3.1 forced PC manufacturers to pay a royalty to Microsoft for every computer shipped, regardless of what operating system it contained.

A further complication was that Star Trek was designed to be source-level compatible, not binary compatible, with the Mac OS. Mac applications would therefore have to be recompiled or rewritten by their developers to run on the x86 architecture, and there was much skepticism as to exactly how much work this would entail.

Fifteen years after Star Trek, support for the x86 architecture was officially included in Mac OS, and then Apple transitioned all desktop computers to the x86 architecture. This was not the direct result of earlier Project Star Trek efforts. The Darwin underpinning used for Mac OS X 10.0 and later included support for the x86 architecture. The remaining non-Darwin portion of Mac OS X (based on OPENSTEP, which ran on Intel processors) was released officially with the introduction of x86 Macintosh computers.

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