Mac OS X Leopard

Developer technologies

• Native support by many libraries and frameworks for
  32-bit applications using those libraries and frameworks should continue to run without the need for emulation or translation.^[37]
• Leopard offers the Objective-C 2.0 runtime, which includes new features such as garbage collection. Xcode 3.0 supports the updated language and was itself rewritten with it.^[38]
• A new framework, Core Animation, allows a developer to create complex animations while specifying only a "start" and a "goal" space. The main goal of Core Animation is to enable the creation of complex animations with small amounts of program code.
• Apple integrates
  Instruments (previously Xray). DTrace provides tools that users, administrators and developers can use to tune the performance of the operating system and the applications that run on it.^[39]
• The new Scripting Bridge allows programmers to use Python 2.5 and Ruby 1.8.6 to interface with the Cocoa frameworks.^[40]
• Ruby on Rails is included in the default install.
• Leopard’s OpenGL stack has been updated to version 2.1, and uses LLVM to increase its vertex processing speed.^[41] Apple has been working to get LLVM integrated into GCC;^[42] LLVM’s use within other operating system facilities has not been announced.
• The Graphics and Media State of the Union address confirmed many other features are possible because of Core Animation, such as live desktops, improvements to Quartz Composer with custom patches, a new PDF Kit for developers, and improvements to QuickTime APIs.
• The FSEvents framework allows applications to register for notifications of changes to a given directory tree.^[43]
• Leopard includes a read-only implementation of the ZFS file system.

In mid-December 2006, a pre-release version of Leopard appeared to include support for Sun’s ZFS.^[44] Jonathan Schwartz, CEO and President of Sun Microsystems, boasted on June 6, 2007, that ZFS had become "the file system" for Leopard.^[45] However, the senior project marketing director for Mac OS X stated on June 11, 2007, that the existing HFS+, not ZFS, would be used in Leopard. Apple later clarified that a read-only version of ZFS would be included.^[46]

• Leopard includes drivers for
  Blu-ray discs using third-party drives, but the included DVD Player software can only play HD DVDs authored by DVD Studio Pro.^[47]
• Leopard includes a framework implementing latent semantic mapping for classifying (e.g. textual) data.
• Leopard is the first operating system with open source BSD code to be certified as fully
  UNIX-compliant.^[48][49] Certification means that software following the Single UNIX Specification can be compiled and run on Leopard without the need for any code modification.^[40] The certification only applies to Leopard when run on Intel processors.^[49]
• Leopard includes
  J2SE 5.0.^[50]

Application Layer Firewall

Leopard ships with two firewall engines: the original BSD IPFW, which was present in earlier releases of Mac OS X, and the new Leopard Application Layer Firewall. Unlike IPFW, which intercepts and filters IP datagrams before the kernel performs significant processing, the Application Layer Firewall operates at the socket layer, bound to individual processes. The Application Layer Firewall can therefore make filtering decisions on a per-application basis. Of the two firewall engines, only the Application Layer Firewall is fully exposed in the Leopard user interface. The new firewall offers less control over individual packet decisions (users can decide to allow or deny connections system-wide or to individual applications, but must use IPFW to set fine-grained TCP/IP header-level policies). It also makes several policy exceptions for system processes: neither mDNSResponder nor programs running with superuser privileges are filtered.^[51]

Sandboxes

Leopard includes kernel-level support for

role-based access control

(RBAC). RBAC is intended to prevent, for example, an application like Mail from editing the password database.

Application Signing

Leopard provides a framework to use public key signatures for code signing to verify, in some circumstances, that code has not been tampered with. Signatures can also be used to ensure that one program replacing another is truly an "update", and carry any special security privileges across to the new version. This reduces the number of user security prompts, and the likelihood of the user being trained to simply clicking "OK" to everything.

Secure Guest Account

Guests can be given access to a Leopard system with an account that the system erases and resets at logout.^[52]

Security features in Leopard have been criticized as weak or ineffective, with the publisher

Apple states the following basic Leopard system requirements, although, for some specific applications and features (such as iChat backdrops) an Intel processor is required:[57]

• Processor: any Intel processor, or PowerPC G5 or G4 (867 MHz and faster) processor
• Optical drive: internal or external DVD drive (for installation of the operating system)
• Memory: minimum 512 MB of
  RAM
  (additional RAM (1 GB) is recommended for development purposes)
• Hard drive capacity: Minimum 9 GB of disk space available.

Leopard’s retail version was not released in separate versions for each type of processor, but instead consisted of one universal release that could run on both PowerPC and Intel processors.^[37] However, the install discs that ship with Intel-based Macs only contain Intel binaries. ^{[citation needed]}

Processor type and speed are checked during installation and installation halted if insufficient; however, Leopard will run on slower G4 processor machines (e.g., a 733 MHz

Some ways of running Leopard on certain unsupported hardware, primarily PowerPC G4 computers with CPU speeds lower than the official requirement of 867 MHz, have been discovered. A common way is use of the program LeopardAssist, which is a bootloader similar in some respects to XPostFacto (used for installing earlier releases of Mac OS X on unsupported G3 and pre-G3 Macs) that uses the Mac’s Open Firmware to tell Leopard that the machine does have a CPU meeting the 867 MHz minimum requirement that the Installer checks for before installation is allowed to commence, when in reality the CPU is slower.^[58] Currently, LeopardAssist only runs on slower G4s and many people have installed Leopard successfully on these older machines.

Users who have access to supported hardware have installed Leopard on the supported machine then simply moved the hard drive to the unsupported machine. Alternatively, the Leopard Installation DVD was booted on a supported Mac, then installed on an unsupported Mac via Firewire Target Disk Mode. Leopard is only compiled for AltiVec-enabled PowerPC processors (G4 and G5) though, as well as Intel, so both of these methods will only work on Macs with G4 or later CPUs. While some of the earlier beta releases were made to run on some later G3 machines (mostly later 800–900 MHz iBooks), no success with the retail version has been officially reported on G3 Macs except for some later iMacs and "Pismo" PowerBook G3s with G4 processor upgrades installed.

For a number of months after Leopard's release it appeared that the only G3 Macs on which Leopard could be run were those with both an aftermarket G4 processor and an AGP graphics card, as failures with the OS partially booting before crashing were reported on older Macs such as the original tray-loading iMacs and the Beige and Blue & White Power Mac G3 (all with G4 upgrades as Leopard will not even begin to load without one) whereas it would boot fine on newer Macs where the Installer restriction had been circumvented. However, more recently it has been reported

Since Apple moved to using Intel processors in their computers, the

Packaging

The retail packaging for Leopard is significantly smaller than it was for previous versions of Mac OS X (although later copies of OS X 10.4 Tiger also came in a similar small box). It also includes a lenticular cover, making the X appear to float above a purple galaxy, somewhat resembling the default Leopard desktop wallpaper.^[61]

Release history

Timeline of Macintosh operating systems

Timeline of Mac operating systems v t e

Compatibility

After Leopard’s release, there were widely reported incidents of new Leopard installs hanging during boot on the blue screen that appears just before the login process starts.

References