Mac OS X

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.

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. 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. Apple has also registered the trademarks Lynx, Cougar, and Leopard for future use.

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

Mac OS X v10.4, giving the version number of the release. Note that Mac OS X 10.4 (without the v) is redundant and is not used by Apple.
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
History
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' NeXT company after he was forced from Apple in 1985. Meanwhile, Apple attempted to create a "next generation" operating system of their 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.

Description

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 (see: iMac) 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 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.x within Mac OS X, so that most older applications run as they would under Mac OS 9.x. In addition, the Carbon APIs were created to permit legacy code to be quickly ported to run natively on both Mac OS X and Mac OS 9.x. The NeXTSTEP/OpenStep APIs are still available, but Apple now calls the technology Cocoa. You can see the NeXTSTEP heritage in the Cocoa APIs by the fact that class names mostly begin with "NS" (for NeXTSTEP). A fourth option for developers is to write applications in the Java platform, which 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 once compiled for the platform. Compiled binaries are normally distributed as Mac OS X Packages; but some may still require command-line configuration or compilation. Projects like Fink and DarwinPorts provide precompiled or preformatted packages for many standard packages.

Version 10.3 was the first to include Apple X11, Apple's version of the X11 graphical interface for Unix applications, as an optional component during install. Apple's implementation is based on XFree86 4.3 and X11R6.6, with its own window manager which mimics the native look, closer integration with Mac OS X and extensions to use the native Quartz rendering system and accelerate OpenGL.

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 128x128 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 (non-modal dialogs attached to specific windows) and drawers.

Interweaving windows (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 is called Quartz Extreme, and was first featured in Mac OS X v10.2 Jaguar.

Expos� (introduced in version 10.3, "Panther") can quickly tile open windows or reveal your desktop.

Pervasive use of Unicode throughout the operating system.

Straightforward architecture for localisation of applications and other code, fully separates language dependencies from the core code of a program.

Criticisms

The client version of Mac OS X did not support the fine-grained access control list file permission method until version 10.4. Previous versions only supported standard UNIX file system permissions.

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. However, the upgrade price for Windows is actually more than the full price for Mac OS X ($199 and $129 respectively from the producers' websites), with the full price for a new version of Windows being more than double the price of the full version of Mac OS X ($299 from Microsoft's website). Also, Apple make an exception for those who purchase a Macintosh between the time a new version of Mac OS X is announced and the time it starts being preinstalled on new machines; these users have been entitled to upgrade for US$9.95.

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.

Versions

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.

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 MacOS 9. This brought Apple much embarrassment when it was discovered that the upgrade CDs were really full-version CDs with a specific file that disabled installation on MacOS 9 systems; Apple subsequently rereleased the CDs in an actual stripped-down format that didn't facilitate installation on such systems.

On August 24 2002, Apple followed up with Mac OS X v10.2 "Jaguar", which brought profound performance enhancements, a newer, sleeker look, and many powerful enhancements (over 150, according to Apple).

Increased support for Microsoft Windows networks

Quartz Extreme for compositing graphics directly on the video card

An adaptive spam mail filter, based on latent semantic indexing

A system-wide repository for contact information in the new Apple Address Book

Apple Rendezvous networking (Apple's implementation of Zeroconf)

iChat: an Apple-branded, officially-supported third party AOL Instant Messenger client

A revamped Finder with searching built directly into every window

Dozens of new Apple Universal Access features

Sherlock 3: Web services (See Watson)

CUPS: The Common Unix Printing System allowed the use of GIMP-print drivers, hpijs drivers etc. for "unsupported" printers. It also allowed - with some user recompilation - printing to serial printers.

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.

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" is due to be released on April 29, 2005. It is promised to contain another 200 or more features, but like Panther, some machines are no longer supported — Tiger requires FireWire.

Spotlight: A tool to quickly find items containing key words on your computer, including the contents of files.

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.

Re-written Unix filesystem utilities, such as cp and rsync, designed to preserve files' resource forks.

An extended permissions system using access control lists.

The current version of Mac OS X is version 10.3.9 (released on April 15, 2005).

As well as the public version numbers which follow the format of 10 followed by the major number followed by the minor number, internally Apple use a "build number" to identify each development version. 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 1Z series would be 2A, followed by 2B, ... 2Y, 2Z, 3A, and so on. When a build is deemed ready for public release, 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, and build 7B85 became 10.3. In late March 2005, Apple declared build 8A425 golden master for version 10.4.