Games - Copland

	Games - Copland

Copland was a project at Apple Computer to create an updated version of the Macintosh operating system. It was to have introduced protected memory, multitasking and a number of new underlying operating system features, yet still be compatible with the vast majority of existing Mac software. Begun in 1994, it was abandoned in August of 1996.

Background

In 1989, managers at Apple had a meeting to plan the future course of Mac OS development. Ideas were written on index cards; features that seemed simple enough to implement in the short term (like adding color to the user interface) were written on blue cards, while more advanced ideas (like an object-oriented file system) were written on pink cards. Development of the ideas contained on both sets of cards was to proceed in parallel, and the two projects were known simply as "blue" and "pink". Apple intended to have the "blue" team (which came to call themselves the "Blue Meanies" after characters in Yellow Submarine) release an updated version of the existing Macintosh operating system in the 1990-1991 timeframe, and the 'pink' team to release an entirely new OS around 1993.

The "blue" team delivered what became known as System 7 only slightly late near the end of 1991, but the "pink" team suffered from second-system effect and continued to slip its release into the indefinite future. Some of the reason for this can be traced to problems that would become endemic as time went on. As 'pink' started to become delayed, engineers on the project jumped ship to work on 'blue' instead. This left the "pink" team constantly struggling for staffing, while upper management ignored the problems. Eventually Apple semi-abandoned the "pink" project by spinning it off to form Taligent.

Originally intended to support a single user running a single application on a non-networked machine with a floppy disk drive for storage, many parts of the System 7 operating system simply did not scale well to the increasing demands of users. In particular the architecture of QuickDraw made it very difficult to introduce multitasking into the system, and the file system was inefficient when used with hard disks.

Several attempts were made by various teams to address these issues with an updated operating system, or at least parts of one, but they ran afoul of internal politics and turf wars. John Sculley, Apple's CEO during this period, largely ignored managing of the company itself while he concentrated on sales and marketing. As a result the engineering departments had no clear direction.

Design

With System 7.5 released in autumn 1994, Apple management decided that the decade-old Macintosh operating system had run its course. The system not only lacked a number of features expected from any modern OS, but was growing increasingly unstable due to the lack of protected memory. The number of crashes suffered by users was increasing all the time, and was becoming a real concern. An entirely new operating system with more advanced features would be needed for the platform to compete with upcoming releases of Microsoft Windows.

The result was a next-generation operating system, code-named Copland after composer Aaron Copland. Copland was to run the Mac OS on top of a microkernel named Nukernel, which handled basic tasks such as application startup and memory handling, leaving all other tasks to a series of semi-special programs known as servers. For instance, networking and file services would not be provided by the kernel itself, but by servers which would be sent requests though interapplication communications. Copland consisted of the combination of Nukernel, various servers, and a suite of application support libraries to provide the well-known Macintosh programming interface.

Application services would be offered through a single program known as the blue box, which essentially encapsulated an existing System 7 operating system inside a single process in a single address space. Mac programs would run inside the blue box much as they did under System 7, as 'co-operative tasks' that used non-re-entrant Toolbox calls. A worst-case scenario was that an application in the blue box would crash, taking down the entire box with it. This would not result in the system as a whole going down, and the blue box could be restarted.

[ Visit the complete Wikipedia entry for Copland ]

Games - Copland

Background

Design

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