Improved administration
Administration is somewhat improved with Snow Leopard. Apple's Server Preferences administrative application in Leopard was available only if Advanced wasn't chosen; we've not used them subsequently because Server Preference choices had no depth and were superficial.
In Snow Leopard, simple basic administrative choices can be performed in Server Preferences, but aren't likely to be used by very many administrators. We wonder why it's still around, save that it's a safe choice for small, civilian-run networks. Server Admin still does most of the work of managing the MacOS server system and its services.
Performance inside performance
Apple attempts to achieve scale for its apps via something called "Grand Central Dispatch" (GCD). The idea behind GCD is to more efficiently use multicore processor resources by aiding parallelism in applications across processors.
The technical explanation of GCD is simple, and programs don't necessarily have to be specifically GCD-enabled to benefit from GCD parallelism, although it helps. Sitting in userspace, the GCD is designed to allow Apple's Snow Leopard to be more efficient in its use of memory and resources for programming needs.
It does this by allowing apps that can sense the GCD to spawn threads that are very small, compared with other operating system (especially Linux) schemes. Apps that simply use GCD-enabled services, like Apache or file services, also get a boost from more efficient MacOS, GCD-enabled infrastructure. Apple released GCD code to open source developer trees under the Apache and MIT licenses after MacOS 10.6/Snow Leopard was released.
Perhaps as a consequence of the now-removed PowerPC support, MacOS 10.6 can take advantage of differing memory models (64-bit) which we believe helped in our SPECjbb2005 test. SPEC's JBB test is an emulation of a business application using Java that delivers a result in Business Operations per Second (BOP).
In an apples-to-apples comparison, Snow Leopard is 4% faster than Leopard. Add in the ability to use large memory pages, and the figure is 21% more BOPs. When we lowered the available total memory but increased the number of Java Virtual Machines servicing SPECjbb2005, the large memory size helped but it didn't appear as though the new GCD helped performance in this benchmark.
Conclusion
Snow Leopard/MacOS 10.6 isn't a blockbuster. It has a few new applications that aren't likely to start an Internet storm. The updates to the existing apps are the polish of this version, one that quietly fixes and augments the applications.
Apple G4/G5 users will likely feel a bit bruised by omission of support or upgrades to this version, but Apple at some point knew it would have to cut off support. Cross-platform support was very good in Leopard, but applications have started to drift into PowerPC-support and Intel-support CPU factions, with Intel rapidly winning by Apple's choice.
There is no reason not to retrofit Snow Leopard into an existing Leopard-based environment. The price at $499 is reasonable ($29 if upgrading from Leopard), but made more expensive by captivity to Apple's comparatively pricey server hardware. As a plug-and-play combination, Apple's controlled Snow Leopard environment provides a seamless experience.
Henderson is principal researcher and Allen is a researcher for ExtremeLabs in Indianapolis. They can be reached at thenderson@extremelabs.com.
Henderson is also a member of the Network World Lab Alliance, a cooperative of the premier reviewers in the network industry each bringing to bear years of practical experience on every review. For more Lab Alliance information, including what it takes to become a member, go to www.networkworld.com/alliance.