Apple Goes 64-Bit with Tiger Release of OS X
by Timothy Prickett Morgan
Apple Computer finally let the cat out of the bag officially, and said that its "Tiger" desktop and server versions of the Mac OS X operating system will begin shipping on April 29. Back in June 2004, when Apple was previewing Tiger at its annual developers conference, the company had promised that the Tiger would ship sometime in the first half of 2005. Apple has met that deadline with a comfortable margin, and this is refreshing to see in a computer industry that often doesn't meet its deadlines.
Mac OS X is probably the most user-friendly and most highly integrated of the Unix platforms on the market today, but is still not perceived as being a mainstream, Unix platform for running core business applications. This is something that Apple clearly wants to change with both the desktop and server implementations of Tiger. Apple is also obviously counting on the Tiger desktop variant, Mac OS X 10.4, to create a lot of excitement and it is the desktop variant that will still make up the bulk of the volumes that Apple ships of the new operating system. Tiger is the fifth version of Mac OS X, and is based on the Mach 3.0 kernel (which supports preemptive and cooperative multitasking, symmetric multiprocessing for machines with multiple processors, and multithreading across processors) and a set of FreeBSD Unix services. That new kernel has improved SMP performance, according to Apple, and the question now is how far Apple wants to push SMP scalability. There is room in the world for four-way Xserve G5 servers, after all. (Apple's machines currently top out at two processors, and this is a limiting factor in the growth of Mac OS X as a platform for commercial processing.)
Underneath the covers of Mac OS X is a BSD Unix environment, called Darwin, that supports all of the standard Unix utilities and scripting languages. The Panther release of Mac OS X already had lots of APIs to help in porting Unix and Linux applications to Mac OS X, and with Tiger, Apple is adding open source libraries to support XML transformations, data persistence, and common Unix services like System V message queues.
Tiger is also interesting in that it will actually support full 64-bit processing on the PowerPC processors that Apple has been shipping for years. Both the prior "Smeagol" 10.2.7 and "Panther" 10.3 releases of Mac OS X ran in a hybrid 32-bit/64-bit mode. Some elements of the Mac architecture were given extended support (which is why the machines running Panther could support more than 4 GB of main memory), but not all elements of the operating system or application software running on top of these Mac OS 10 releases could run in 64-bit mode. Luckily for Apple, IBM planned for the PowerPC and later Power architectures to support a native 32-bit mode inside a fuller 64-bit processor, allowing for hybrid processing that allowed certain code to run in 32-bit mode without modification and other code to run in 64-bit mode if it was recompiled to take advantage of the extended memory addressing. So, for instance, Apple could recode the memory management features of Panther and give it a larger memory space to play in. However, with Tiger, the operating system is a true 64-bit environment, top to bottom, and now software vendors creating applications can reach down into the 64-bit PowerPC processors in those Apple systems and make use of the 64-bit processing the hardware has. Apple said that it has encoded 64-bit memory using the LP64 data model, one of three different data models that fit the Unix specification. Incidentally, no one has to port 32-bit applications to 64-bit to run on Tiger--Apple is not stupid. These 32-bit applications will continue to run in native mode as long as IBM's PowerPC chips support the hybrid 32-bit/64-bit architecture.
The desktop implementation of Tiger comes with an integrated desktop search engine called Spotlight, which can scan and organize the contents of a Mac system. Spotlight is constantly updating its file indexes as end users add new stuff to their machines, and Spotlight has been integrated in the Mail, Address Book, Finder, and System Preferences features of the operating system. Back in June, Apple talked vaguely about a new feature for Tiger called Dashboard, which made it seem like a system management program, but it actually turns out that Dashboard is an architecture for creating little "widget" applications using HTML and Java that might be useful for end users; Apple is including 14 such widgets in the Tiger desktop, including an iTunes player (of course), a weather center, a stock ticker, a dictionary, a phone book, a translator, a calendar, and others. iChat collaboration in the desktop has a new audio/video codec that allows audio conferences of up to 10 people and video conferences of up to four people. Apple has also integrated a desktop scripting environment called Automator that allows end users to automate repetitive tasks without resorting to programming in C. Apple has also embedded an RSS reader in the Safari Web browser that is built into Mac OS X and added in its new QuickTime 7 media player.
Tiger Server includes Weblog Server, a variant of the open-source Blojsom Weblog server that has been integrated with the operating system (including Kerberos authentication and LDAP directory support); it can create RSS news feeds. Tiger Server also has an iChat instant messaging server. Both the desktop and the server variants of Tiger also have Apple's own grid computing software, Xgrid 1.0, which allows desktops and servers to aggregate their excess computing capacity into grids and share it for number-crunching work that is normally associated with supercomputers. (Xgrid makes Macs into supercomputers, actually.) Apple said that Tiger Server has over 200 new features, and integrates over 100 open source projects into the Mac OS system. Tiger Server has improved Windows compatibility, and now it supports the access control lists and the native file permissions of the Windows XP desktop and the Windows 2003 Server's Active Directory. Tiger has a neat feature called Software Update Server that allows system administrators to cache local copies of updates to Mac OS X and allow end users to update machines locally rather than through the Internet. Finally, Tiger Server supports Ethernet link aggregation and network interface failover, which in plain English means that multiple physical Ethernet adapters can be ganged up to look like a giant virtual Ethernet port, which can boost bandwidth significantly, simplify networks (since they all have a single IP), and improve resiliency (since a failed network adapter doesn't take out an IP address).
The Tiger desktop software will go on sale in Apple's stores and through resellers in the evening of April 29 for $129, and you can preorder it now at those stores. Apple is also offering a family pack license for five machines in a single residence location. The desktop software runs on any G3, G4, or G5 Mac with a minimum of 256 MB of main memory. Tiger Server cost $499 for a 10-user license per server, and $999 per server for an unlimited user license, which is not exorbitant compared to commercial Unix, Linux, and Windows licenses for uniprocessor and two-way servers. Tiger Server also runs on any G3, G4, or G5 Mac or Xserve system with 256 MB of RAM; it requires 4 GB of free disk space.