Mac OS X

Template:Infobox OS Mac OS X is the latest version of the Mac OS, the operating system software for Macintosh computers. Mac OS X was first commercially released in 2001. It consists of two main parts: Darwin, an open source Unix-like environment which is based on the BSD source tree and the Mach microkernel, adapted and further developed by Apple Computer with involvement from independent developers; and a proprietary GUI named Aqua, developed by Apple.

Mac OS X Server was also released in 2001. Architecturally identical to the workstation (client) version, it is differentiated by the inclusion of workgroup management and administration software tools, which provide simplified access to key network services, such as a mail server, a Samba server, a directory server, and a domain name server. It also has a different licensing model.



The character X is a Roman numeral and is officially pronounced "ten", continuing the numbering of previous Macintosh operating systems such as Mac OS 8 and Mac OS 9. Some people read it as the letter X and pronounce it "ex". One reason for this interpretation is the tradition of giving Unix-like operating system names ending with the letter x (e.g. AIX, IRIX, Linux, Minix, Ultrix, Xenix). Another reason is Apple's tendency to refer to specific versions in print as (for example) "Mac OS X version 10.4".

Mac OS X versions are named after large felines. Prior to its release, version 10.0 was code named Cheetah internally at Apple, and version 10.1 was codenamed Puma. Version 10.2 was named Jaguar in Apple's product marketing, and 10.3 was similarly named Panther. Version 10.4 has been named Tiger. Leopard has been announced as the name for the next release of the operating system. Apple has also registered the trademarks Lynx and Cougar for future use.

Apple faced a lawsuit from a computer retailer named TigerDirect regarding its use of the name "Tiger". However, on 16 May 2005 the Florida Federal Court ruled that Apple's use of the name "Tiger" does not infringe upon TigerDirect's trademark.

Apple's web site and literature refer to the specific Mac OS X releases in any of four different ways:

  • Mac OS X v10.4, giving the version number of the release.
  • Mac OS X Tiger, giving the name of the release.
  • Mac OS X v10.4 "Tiger", giving the version number and name. Apple's usage sometimes omits the quotation marks.
  • "Tiger", simply the name of the release


Main article: Mac OS X history

Despite its branding as simply "version 10" of the Mac OS, it has a history largely independent of the earlier Mac OS releases. It is based on the Mach kernel and the BSD implementation of UNIX, which were incorporated into NeXTSTEP, the object-oriented operating system developed by Steve Jobs's NeXT company after he was forced from Apple in 1985. Meanwhile, Apple attempted to create a "next generation" operating system of its own (see Taligent and Copland), but with little success. Eventually, NeXT's OS—by then called OPENSTEP—was selected to form the basis for Apple's next OS, and the company purchased NeXT outright. Jobs was rehired, and later returned to the leadership of the company, shepherding the transformation of the programmer-friendly OPENSTEP into a system that would be welcomed by Apple's primary market of home users and creative professionals, as a project known as Rhapsody. After some missteps which threatened the loyalty of independent developers to Mac OS, and changes of strategy to ease the transition from Mac OS 9 to the new system, Rhapsody evolved into Mac OS X.


The box for  "Tiger"
The box for Mac OS X v10.4 "Tiger"

Mac OS X is a radical departure from previous Macintosh operating systems, as its underlying code base is completely different from previous versions. Although the most significant architectural changes were under the surface, the Aqua GUI was the most striking and visible new feature. The use of soft edges, translucent colors and pinstripes (similar to the hardware of the first iMacs) brought more color and texture to the windows and controls on the Desktop than OS 9's "Platinum" appearance offered, raising a great deal of controversy among users. Many older Macintosh users decried the interface as "toy-like" and lacking in professional polish, while others hailed the new GUI as a revolutionary Apple innovation. The look was instantly recognizable and even before the first version of Mac OS X was released, third-party developers started producing skins for skinnable applications like Winamp that looked like the Aqua interface. Apple has threatened legal action against people who make or distribute software which provides an interface which they claim is derived from their copyrighted design.

This combination of GUI and kernel has recently become the most popular-selling Unix-like environment to date by sheer number of systems shipped.


Mac OS X retains compatibility with older Mac OS applications by providing an emulation environment called Classic, which allows users to run Mac OS 9 as a process within Mac OS X, so that most older applications run as they would under the older operating system. In addition, the Carbon APIs for Mac OS 9 and Mac OS X were created to permit code to be written to run natively on both systems. The OpenStep APIs are still available, but Apple now calls the technology Cocoa. (This heritage is visible in the Cocoa APIs, in which the class names mostly begin with "NS" for NeXTSTEP.) A fourth option for developers is to write applications in the Java platform, which Mac OS X supports as a "first class citizen" - in practice this means that Java applications fit as neatly into the operating system as possible while still being "cross-platform", and that GUIs, while being written in Swing, look almost exactly like native Cocoa interfaces.

Mac OS X can run many BSD or Linux software packages, as long as they have been compiled for the platform. Compiled binaries are normally distributed as Mac OS X packages, but some may require command-line configuration or compilation. Projects such as Fink and DarwinPorts provide precompiled or preformatted packages for many standard packages. Since version 10.3, Mac OS X has included Apple X11, the company's version of the X11 graphical interface for Unix applications, as an optional component during installation. Apple's implementation is based on XFree86 4.3 and X11R6.6, with a window manager which mimics the Mac OS X look, closer integration with Mac OS X, and extensions to use the native Quartz rendering system and to accelerate OpenGL. Earlier versions of Mac OS X can run X11 applications using XDarwin.

For the early releases of Mac OS X, the standard hardware platform supported was the line of Macintosh computers (laptop, desktop, or server) based on PowerPC G3, G4, and G5 processors. Later versions of Mac OS X discontinued support for some older hardware; for example, Panther does not support "beige" G3s, and Tiger does not support systems that pre-date Apple's introduction of FireWire ports. However, free tools such as XPostFacto have enabled installation of Mac OS X on certain older systems not officially supported by Apple, including some pre-G3 systems. The operating system offers the same functionality on all supported hardware, with the exception of fundamental hardware limitations (e.g. CD-ROM drives cannot write to CDs) and performance enhancements possible only with more advanced equipment (e.g. graphics acceleration).

On June 6, 2005, Steve Jobs announced in his keynote address at the WWDC that Apple will be switching from PowerPC to Intel processors over the following two years[1] (, and that Mac OS X will support both platforms during this transition. Support for the PowerPC platform will remain in version 10.5, though it is unclear how long this dual-architecture support will be continued. (Mac OS support for the original Motorola 68k architecture continued for about four years after the introduction of PowerPC systems.) A new version of Xcode supports building "universal binaries" that will run on either architecture. PowerPC binaries will be supported on Intel-based Macs using an emulator called Rosetta. Jobs also confirmed rumors that Apple has had versions of Mac OS X running on Intel processors for most of its developmental life. Such crossplatform capability already existed in OS X's lineage -- the predecessor of OS X, OPENSTEP, had been ported to many architectures, including Intel's x86, and a port to x86 of the core operating system of OS X, Apple Darwin, has been available as a free download since OS X was first released.

Notable features

  • Uses a subset of the Portable Document Format (PDF) as the basis of its Quartz imaging model.
  • Full color, continuously scalable icons (up to 256x256 pixels).
  • Drop shadow around window and isolated text elements to provide a sense of depth.
  • Global spell checking and other powerful tools thanks to NeXT-style application services.
  • Anti-aliasing of widgets, text, graphics and window elements.
  • New interface elements including sheets (document modal dialogs attached to specific windows) and drawers.
  • Interweaving windows of different applications (not necessarily adjacent in the visible stacking order).
  • ColorSync color matching built into the core drawing engine (for print and multimedia professionals).
  • OpenGL (introduced in version 10.2) composites windows onto the screen to allow hardware accelerated drawing. This technology is called Quartz Extreme.
  • Expos (introduced in version 10.3) can quickly tile open windows or reveal the desktop.
  • Pervasive use of Unicode throughout the operating system.
  • Straightforward architecture for localization of applications and other code, fully separating language dependencies from the core code of a program.
  • FileVault (introduced in version 10.3) encrypts the user's Home folder with Advanced Encryption Standard (AES) 128-bit keys.
  • Dashboard (introduced in version 10.4) supports small applications ("widgets") that can be called up and dismissed in one keystroke.
  • Spotlight search technology (introduced in version 10.4) allows rapid real-time searches of data files, mail messages, photos, and other information, based on item properties and/or content.


In comparison to Microsoft Windows, some critics point to the lack of upgrade pricing on Mac OS X; users of previous versions have to pay full price for a new version. This is in part a semantic argument, depending on whether a retail Mac OS X package is considered an "upgrade" or not. On one hand, it can only be used on a Mac, all of which were sold with some version of the Mac OS, so it is arguably an upgrade. On the other hand, no price distinction is made between upgrading version 9.0 or version 10.3 to version 10.4, suggesting that consumers are buying a full license in either case, or at least receiving no credit for intervening upgrades. Furthermore, customers who purchase a Macintosh between the time a new version of Mac OS X is announced and the time it starts shipping preinstalled on new machines have typically been given upgrades at a much smaller cost (US$9.95-19.95). Meanwhile, the upgrade price for Windows varies substantially depending on volume purchase agreements, Home vs. Pro editions, etc. making direct comparisons difficult. In some cases, the upgrade price for Windows exceeds that of Mac OS X, suggesting that this criticism is moot.

The Open Group has criticized Apple for use of the term "Unix" in advertisements for Mac OS X as Apple has not had the OS officially certified, and their use of the term could constitute a violation of trademark. Apple claims that they use the term as a genericized trademark and that the cost of certification would make the OS prohibitively expensive, although The Open Group has stated that there is a US$110,000 upper limit on the cost of certification for one company.


Missing image
Box artwork for Mac OS X versions Cheetah/Puma, Jaguar, Panther, and Tiger.

Internally, Apple uses a "build number" to identify each development version of Mac OS X. There may be many development versions each week. Under Apple's guidelines, the first development version of a product starts with build 1A1. Minor revisions to that are 1A2, 1A3, 1A4, and so on; the first major development revision becomes 1B1 (and minor revisions to that would be 1B2, 1B3, etc.), the next major revision would be 1C1, and so forth. The next major revision after the last 1_ series would be 2A, followed by 2B. The transition from one letter to the next occurs with changes in the minor release number. For instance, the first build of Panther (10.3) was 7A1. The first public release was 7B85; the last, 10.3.9, was 7W98. But the next build of OS X was 10.4, 8A1. When a build is chosen as the next public release of Mac OS X, it is given a public version number. Build 4K78 was chosen to be Mac OS X version 10.0, build 5G64 became 10.1, build 6C115 became 10.2, build 7B85 became 10.3, and build 8A428 became 10.4.

The current version of Mac OS X is version 10.4.1 (released on May 16, 2005).

Mac OS X v10.0 (Cheetah)

On March 24, 2001, Apple released Mac OS X v10.0 (codenamed Cheetah). It was praised for its completeness and stability at such an early point in its development (it being a total departure from previous Apple releases). Despite this, it was criticized for being slow, leading many (including Steve Jobs) to consider it merely a very good "beta" release.

Mac OS X v10.1 (Puma)

Later that year on September 25, 2001, Mac OS X v10.1 (codenamed Puma) was released, increasing the performance of the system as well as providing missing features, such as DVD playback. Because of the poor reputation of 10.0, Apple released 10.1 as a free upgrade CD for 10.0 users, in addition to the US$129 boxed version for people running only Mac OS 9. This brought Apple much embarrassment when it was discovered that the upgrade CDs were actually full install CDs that could be used with Mac OS 9 systems by removing a specific file; Apple subsequently rereleased the CDs in an actual stripped-down format that didn't facilitate installation on such systems.

Mac OS X v10.2 "Jaguar"

On August 24, 2002, Apple followed up with Mac OS X v10.2 "Jaguar" (the first release to publicly bear its cat name), which brought profound performance enhancements, a newer, sleeker look, and many powerful enhancements (over 150, according to Apple), among them:

Mac OS X v10.2 was never officially referred to as Jaguar in the United Kingdom due to an agreement with the automobile manufacturer Jaguar, although boxes and CDs still bore the Jaguar-skin logo.

Mac OS X v10.3 "Panther"

Mac OS X v10.3 "Panther" was released on October 24, 2003. In addition to providing much improved performance, it also incorporated the most extensive update yet to the user interface. The update included as many or more new features as Jaguar the year before. On the other hand, support for some older "beige era" G3 computers was discontinued. New features of "Panther" include:

  • Updated Finder, incorporating a brushed-metal interface and fast-searching
  • Expos: a new system to manipulate windows
  • Fast User Switching: allows a user to remain logged in while another user logs in
  • iChat AV which added video-conferencing features to iChat
  • Improved PDF rendering to allow for extremely fast PDF viewing
  • Built-in faxing support
  • Much greater Microsoft Windows interoperability
  • FileVault: on the fly encryption and decryption of a user's home folder
  • Increased speed across the entire system with more support for the G5

Mac OS X v10.4 "Tiger"

Mac OS X v10.4 "Tiger" was released on April 29, 2005. Apple stated that Tiger contains more than 200 new features, but as with the release of Panther, certain older machines have been dropped from the list of supported hardware; Tiger requires FireWire. Among the new features of "Tiger":

  • Spotlight: A fast content and metadata-based file search tool, which quickly finds items containing the key words you search for.
  • Dashboard: Widgets for common tasks available on a desktop overlay just a click away.
  • iChat: A new version supports the H.264 video codec for conferencing and allows for multi-party audio and video chats.
  • QuickTime 7: the new version includes H.264 support and a completely re-written interface.
  • Safari 2: this new version of the system's default web browser includes the ability to view RSS feeds directly in the browser, among other new features.
  • Automator: automates repetitive tasks without programming.
  • Core Image and Core Video: allows additional effects in video and image editing to be performed in real time.
  • 64-bit memory support for the new G5, using the LP64 system.
  • Updated Unix utilities, such as cp and rsync, that can preserve HFS Plus metadata and resource forks.
  • An extended permissions system using access control lists.

Mac OS X v10.5 "Leopard"

Mac OS X v10.5 "Leopard" was announced at the Worldwide Developers Conference on June 6, 2005, due to be released at the end of 2006 or early 2007. Apple has said that it will support both PowerPC- and Intel- based Macintosh computers.

See also

External links

  • Apple: Mac OS X ( — Official page
  • What is OS X? ( ( — A balanced, accessible overview of the Mac OS X operating system
  • Mac OS X: Welcome to the jungle ( — A look inside the Mac OS X software ecology (Free Software Magazine, March 2005)
  • [2] ( — A comprehensive look at OS X and Windows XP

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