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Mac OS X (officially pronounced "Mac OS Ten") is a line of proprietary, graphical operating systems developed, sold, and marketed by Apple Computer, the latest of which is included with all currently shipping Apple Macintosh computers. Mac OS X is the successor to the original Mac OS, which had been Apple's primary operating system since 1984. Unlike its predecessor, Mac OS X is a multi-user, pre-emptively multitasking, Unix-like operating system built on technology that had been developed at NeXT through the second half of the 1980's and up until Apple Computer purchased the company in early 1997. The operating system was first released in 1999 as Mac OS X Server 1.0, with a desktop-oriented version (Mac OS X v10.0) following in March, 2001.

The server edition, Mac OS X Server, is architecturally identical to its desktop counterpart but usually runs on Apple's line of Macintosh server hardware. Mac OS X Server includes workgroup management and administration software tools that provide simplified access to key network services, including a mail server, a Samba server, a directory server, and a domain name server.

History

Despite its branding as simply "version 10" of the Mac OS, Mac OS X has a history that is almost completely independent of the earlier Mac OS releases.

Mac OS X 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' NeXT company after he left Apple in 1985. Meanwhile, during the years without Jobs at the helm, Apple attempted to create a "next-generation" operating system of its own (see Taligent and Copland) with little success.

Eventually, NeXT's OS—called OPENSTEP at the time—was selected to form the basis for Apple's next OS, and Apple purchased NeXT outright. Jobs was re-hired, 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.

Mac OS X has evolved through its successive versions, away from a focus on backward compatibility and toward "digital lifestyle" applications such as the iLife suite, enhanced business applications (iWork), and integrated home entertainment (the Front Row media center).

Description

Mac OS X was a radical departure from previous Macintosh operating systems as its underlying code base is completely different from previous versions. Its core, named Darwin, is an open source, Unix-like operating system, built around the XNU kernel with standard Unix facilities available from the command line interface. On top of this core, Apple designed and developed a number of proprietary closed source components, including the Aqua user interface and the Finder shell.

Mac OS X included a number of features intended to make the operating system more stable and reliable than Apple's previous operating systems. Pre-emptive multitasking and memory protection, for example, improved the ability of the operating system to run multiple applications simultaneously without them interrupting or corrupting each other. Many aspects of Mac OS X's architecture are derived from OPENSTEP, which was designed with portability in mind, thus easing the transition from one platform to another. (For example, NEXTSTEP was ported from the original 68k-based NeXT workstations to PA-RISC/SPARC/x86-based machines before NeXT was purchased by Apple, and OPENSTEP was subsequently ported to the PowerPC architecture as part of Apple's Rhapsody project.)

The most visible change was the Aqua graphical user interface. 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 had offered. Some, including numerous users of the older versions of the operating system, decried the new look as "cutesy" Web-forum post by 'millennium'. and lacking in professional polish. Others, however, hailed Aqua as being a bold and innovative step forward in a time when user interfaces were seen as being "dull and boring". Despite the controversy, the look was instantly recognizable, and even before the first version of Mac OS X was released, third-party developers started producing skins for customizable applications, like Winamp, similar to the Aqua appearance. (To some extent, Apple has used the successful transition to this new design as leverage, at various times threatening legal action against people who make or distribute software with an interface the company claims is derived from its copyrighted design (mirrored from web.archive.org).

Mac OS X includes its own software development tools, most prominently an integrated development environment called Xcode. Xcode provides interfaces to compilers that support several programming languages including C, C++, Objective-C, and Java. It supports the ability to target both platforms for which Mac OS X is sold, allowing an application to be built to run only on PowerPC, only on x86, or on both processors as a Universal Binary.

Compatibility

PowerPC

PowerPC versions of Mac OS X retain 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 has supported 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. Traditionally, Cocoa programs have been mostly written in Objective-C, with Java as an alternative. However, on July 11, 2005, Apple announced that "features added to Cocoa in Mac OS X versions later than 10.4 will not be added to the Cocoa-Java programming interface."

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 X11.app, 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 full 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, a patch can be applied to the installation disc, or free tools such as XPostFacto have enabled installation of versions of Mac OS X on certain older systems not officially supported by Apple, including some pre-G3 systems. Except for features requiring specific hardware (e.g. graphics acceleration, DVD writing), the operating system offers the same functionality on all supported hardware.

Intel

In April 2002, eWeek reported a rumor that Apple had a version of Mac OS X running on x86 processors, code-named Marklar. The idea behind Marklar was to keep Mac OS X running on an alternative platform should Apple become dissatisfied with the progress of the PowerPC platform. These rumors subsided until late in May 2005, when CNet reported that Apple would unveil Marklar in the coming months.

On June 6, 2005, Steve Jobs confirmed these rumors when he announced in his keynote address at the annual Apple Worldwide Developers Conference that Apple will be transitioning from PowerPC to Intel processors over the following two years, and that Mac OS X will support both platforms during this transition. The last time that Apple switched CPU families—from the Motorola 68K CPU to the IBM/Motorola PowerPC—Apple included a Motorola 68K emulator in the new OS that made almost all 68K software work automatically with legacy hardware. Apple has supported the 68K emulator for 11 years; however, Apple will be dropping support for the 68K emulator during the transition to Intel CPUs. Included in the new OS for the Intel-based Macs is a new PowerPC emulator, named "Rosetta", that enables software compiled for PowerPC Mac OS X to run on Intel Mac OS X machines. However, Apple dropped support for Classic mode on the new Intel Macs. (Third party emulation software, like Mini vMac, Basilisk II, and SheepShaver, provides support for some early versions of Mac OS.) A new version of Xcode and the underlying command-line compilers support building Universal Binaries that will run on either architecture. Apple's press release, announcing the transition to Intel.

Software developers can support the new Intel Macs in any of the following ways:

  1. They can continue to ship PowerPC-only software, which will automatically work by using the Rosetta emulator which is included with the new OS that runs on Intel-based Macs.
  2. They can ship Universal Binaries, which include both the PowerPC and x86 versions of their application. When the user opens the application, depending upon which CPU the Mac has, the appropriate version of the application will be run automatically.
  3. They can ship x86-only Mac OS X applications that will run only on the new Intel-based Macs.

Currently, a lot of software is available only for PowerPC, and is supported with Rosetta. However, Apple encourages Developers to produce Universal Binaries with support for both PowerPC and x86; that software should run faster on Intel-based Macs than would PowerPC-only software running on Rosetta, and some PowerPC software, such as kernel extensions and System Preferences plugins, is not supported on Intel Macs. Option 3 will likely start to be the norm several years from now when the demand for PowerPC software drops off.

Support for the PowerPC platform will remain in version 10.5, though it is unclear how long this dual-architecture support will be continued—but since Apple supported the Motorola 68K family for eleven years after the introduction of PowerPC systems, it is likely that they will support the PowerPC Macs for many years to come. 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 Mac OS X's lineage—the predecessor of Mac OS X, OPENSTEP, had been ported to many architectures, including Intel's x86, and a port to x86 of the core operating system of Mac OS X, Darwin, has been available as a free download since Mac OS X was first released. Also note that Apple stated that Mac OS would only run on Apple x86 systems, not PCs, but several people have been using a development version of the OS on non-Apple machines.

Prominent features

  • Full-color, continuously-scalable icons.
  • Drop shadows around window and isolated text elements to provide a sense of depth.
  • Global application services - spell checker, special characters palette, color picker, font chooser and dictionary.
  • 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 composites windows onto the screen to allow hardware accelerated drawing. This technology (introduced in version 10.2) is called Quartz Extreme.
  • Exposé (introduced in version 10.3) Instantly display all open windows as thumbnails for easy navigation to different tasks, display all open windows as thumbnails from the current application, and hide all windows to access 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 (meta data) and/or content.
  • Automator (introduced in version 10.4) an application designed to create an automatic work-flow for different tasks.
  • Smart Folders (introduced in version 10.4) allow for dynamically updated folders depending on a set criteria.
  • A well defined set of Human Interface Guidelines followed by almost all applications giving them intuitive, consistent user interface and keyboard shortcuts.
  • Xgrid allows networked Macs to form a distributed computing system.
  • Built in virtual file system images .dmg supporting encryption and compression, and optionally read/write capability.

Pricing

Mac OS X comes included in the price for new Macs. Minor upgrades are free and can be downloaded using Software Update. Major upgrades cost US$129 from Apple. There is also a US$199 "Family Pack" version of Mac OS X that comes with 5 licenses for home users who have more than one Mac at home. Developers can register for free with the Apple Developer Connection (ADC) to download developer tools such as Xcode and documentation. ADC also offers several for-pay plans including both shipping and beta versions of Mac OS X. Student and educator pricing on Mac OS X software is roughly 10% to 50% lower than standard retail pricing. The Mac OS X Server 10-client license costs US$499 and an unlimited client license is US$999 as of April 1, 2006.

Naming

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. However, it is common to read it as the letter X and pronounce it "ex". One possible reason for this interpretation is the tradition of giving Unix-like operating systems names that contain the letter "X". (AIX, A/UX, HP-UX, IRIX, Linux, Minix, Ultrix, Xenix, NeXT). Another possible reason is Apple's tendency to refer to specific versions in print (for example, "Mac OS X version 10.4").

Mac OS X versions are named after big cats. Prior to its release, version 10.0 was code named "Cheetah" internally at Apple, and version 10.1 was code named internally as "Puma". After the immense buzz surrounding Version 10.2, codenamed "Jaguar", Apple's product marketing began openly using the code name to promote the operating system. 10.3 was similarly marketed as "Panther". Version 10.4 is marketed as "Tiger". "Leopard" has been announced as the name for the next release of the operating system. Apple has also registered "Lynx" and "Cougar" as trademarks.

Apple faced a lawsuit from a computer retailer named Tiger Direct 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 Tiger Direct's trademark.

On a side note, Java version 5.0 (also known as version 1.5) from Sun Microsystems is named "Tiger" which may cause some confusion because it can be installed into Macs running Mac OS X.

Versions

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 Mac 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 10.4.7 (released on June 27, 2006). It is build 8J135 for PowerPC and 8J2135 for Intel.

10.4.4 was the first public version of Mac OS X to run on both PPC (build 8G32) and Intel-based Macs (8G1165). All previous versions of Mac OS X have Intel counterparts, but those were never publicized or made available to end-users.

Mac OS X v10.0 (Cheetah)

On March 24, 2001, Apple released Mac OS X v10.0 (internally codenamed Cheetah). The initial version was slow, not feature complete, and had very few applications available at the time of its launch, mostly from independent developers. Many critics suggested that while the OS was not ready for mainstream adoption, they recognized the importance of its initial launch as a base on which to improve. Simply releasing Mac OS X was received by the Macintosh community as a great accomplishment, for attempts to completely overhaul the Mac OS had been underway since 1996, and delayed by countless setbacks. Following a few minor bug fixes, kernel panics became much less frequent, and Mac OS X began garnering praise for its stability at an early point in its development. It was criticized for being slow, with performance not much improved over the previous September's release of Mac OS X Public Beta.

Mac OS X v10.1 (Puma)

Later that year on September 25, 2001, Mac OS X v10.1 (internally codenamed Puma) was released, increasing the performance of the system as well as providing missing features, such as DVD playback. 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. 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 re-released 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 use its code name as part of the branding) 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.

Some consider version 10.2, or Jaguar, the "first good release" of Mac OS X. Due to significant API changes, most developers don't support versions 10.0 or 10.1 any longer.

Also, the famous Happy Mac that had served Mac users for almost 18 years during a Macintosh's startup sequence was replaced with a large grey Apple logo with the introduction of Mac OS X 10.2.

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 had the year before. On the other hand, support for some early G3 computers such as "beige" Power Macs and "WallStreet" PowerBooks was discontinued. New features of "Panther" include:

  • Updated Finder, incorporating a brushed-metal interface, customizable sidebar and fast-searching
  • Exposé: a new system to manipulate and view 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 faster 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
  • Safari (web browser)

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. As with the release of Panther certain older machines have been dropped from the list of supported hardware; Tiger requires a Mac with built-in FireWire ports. Among the new features of "Tiger":

 

This article is licensed under the GNU Free Documentation License. It uses material from the "Mac OS X".

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