Towards Mac OS X
After Rhapsody's DR2 release, Apple would still alter its operating system strategy, but would finally be on its way towards achieving its goal of having a "new" system. It would further take three years to reach that goal however. We shall refer to a pictorial approximation of the progression towards Mac OS X in the discussion that follows.
Mac OS X Server 1.x
As people were expecting a DR3 release of Rhapsody, Apple announced Mac OS X Server 1.0 in March 1999, which could be considered an improved Rhapsody. It was bundled with WebObjects, a QuickTime streaming server, a collection of developer tools, the Apache web server, facilities for booting and administering over the network, etc.
Apple also announced an initiative called Darwin, a fork of the developer release of Rhapsody. Darwin would become the open source core of Apple's systems.
Over the next three years, as updates would be released for the server product, development of the "client" version would continue, with the server sharing many of the client improvements.
Mac OS X Developer Previews
There were four Developer Preview releases of Mac OS X, named DP1-4. Examples of improvements made during the DP releases include:
- An implementation of the Carbon API was added (DP1). Carbon represented an overhaul of the "classic" Mac OS APIs - pruned, extended, or modified to run in the more modern Mac OS X environment. Carbon would also help Mac OS applications in transitioning to Mac OS X. For example, a Classic application would require an installation of Mac OS 9 to run under Mac OS X, while Carbon applications would run as native applications both under Mac OS 9 and Mac OS X.
Note that Carbon is sometimes perceived as "the old" API. While Carbon indeed contains modernized versions of many old APIs, it also provides functionality that may not be available to other APIs. Parts of Carbon are complementary to "new" APIs like Cocoa.
MacOS.app, the application implementing the Blue Box, became
- The Yellow Box evolved into Cocoa, perhaps alluding to the fact that the API would be available in Java as well (DP2).
- The Aqua user-interface was introduced (DP3).
Mac OS X Public Beta
A $29.95 beta version came out in September 2000 as a publicly available preview release. A message on the cover (from Apple to the Beta Testers) said: "You are holding the future of the Macintosh in your hands".
While ostensibly lacking in stability and performance, and missing important features, the Beta was a demonstration of a number of important Apple technologies at work, at least for those who were not following the DP releases: the Darwin core with its xnu kernel, the PDF-based Quartz graphics system, the Aqua interface with its Dock, and many others.
With Darwin, Apple would continually leverage a lot of existing open source software by using it for, and often integrating it with Mac OS X.
The Extra New Kernel
Darwin's kernel is called xnu. You could consider it an acronym for "X is Not Unix", or a tribute to the fact that it is indeed the NuKernel for Mac OS X.
xnu is largely based on Mach and FreeBSD, but includes code and concepts from various sources, such as the formerly Apple supported MkLinux effort, work done on Mach at the University of Utah, NetBSD, OpenBSD, and some others.
Mac OS X 10.x
Mac OS X 10.0 was released on March 24, 2001. Soon, Mac OS X Server's versioning scheme was revised to synchronize it with the client system's. Since then, the trend has been that new versions of the client usually come out first, followed by the same revision for the server soon after.
The following major Mac OS X releases exist at the time of this writing (the codenames are all taken from felid taxonomy):
|10.0||Cheetah||March 24, 2001|
|10.1||Puma||September 29, 2001|
|10.2||Jaguar||August 24, 2002|
|10.3||Panther||October 24, 2003|
10.0 included Apple's first two "Digital Lifestyle" applications: iMovie and iTunes. 10.1 introduced iDVD.
The Carbon API implementation was complete enough in 10.1 to allow for important 3rd party applications such as Adobe Photoshop to be released for Mac OS X.
10.2 was a significant improvement in most areas. It also introduced Quartz Extreme, an integrated hardware acceleration layer for rendering on-screen objects by compositing them using primarily the GPU on supported graphics cards.
Hereafter, Apple introduced new applications and incorporated technologies in Mac OS X at a bewildering pace. Consider examples like integrated Address Book, Mail, and Chat, an implementation of ZeroConf Networking (called Rendezvous by Apple), iPhoto for digital photo management, the Safari web browser, an optimized X Window System implementation, and many more.
10.3 added many productivity and security features.
After the early releases of Mac OS X, the system's evolution almost makes it appear as if Apple knew what to add to Mac OS X to make it worthwhile for new users to adopt it, and existing users to appreciate it more. It is even more commendable that Apple could create a system appealing to, and serving the needs of people with vastly different interests, abilities, and experience.
A somewhat more detailed technical description of Mac OS X itself can be found in the book Mac OS X Internals.