Snow Leopard Review: Security
Security in Snow Leopard is a mixed bag of good ideas and bad implementation.
NX: Non-Executable Memory Space
Snow Leopard, and any application that runs under Snow Leopard, sets all writeable memory as non-executable. What this means is that one of the most common methods used to gain control of a computer - the injection of arbitrary code into the memory used by an application - will become ineffectual. Because all writeable memory will be marked as non-executable, any instructions found there will not be run by the OS or any applications.
Address Space Layout Randomization (ASLR)
Apple introduced ASLR in Leopard, but it was fundamentally flawed. Theoretically, every time an application, or any supporting code, is launched, ASLR places it in a random location in the Mac’s memory. This would make attacks based on known memory locations almost impossible. But Apple kept some core services in the same locations, making them an easy target. Snow Leopard offers no improvements to the ASLR system.
Malware Download Detector
Snow Leopard scans files downloaded via Safari, Mail, and iChat for known malware. The problem is that the malware list currently only contains two known Trojans. It’s believed that Apple will update the malware list using OS X’s built-in Software Update function.
It’s not clear whether the malware detection application works with all downloads or just files downloaded through the Apple applications included with the OS.
Snow Leopard Review: 64-Bit and Speed
Apple spent a great deal of time making most of the built-in applications, as well as supporting programming libraries, frameworks, and services, 64-bit. Why the push to 64-bit? Mainly speed, although enhanced hardware capabilities and new support for massive amounts of available memory were also major considerations.
The speed increase comes about for various reasons, but the main reason is that when run in 64-bit mode, Intel processors have twice the number of internal registers as their 32-bit counterparts. Internal registers are used to store data that programs will make use of quickly. By having twice the number of registers, more data can be stored within the processor, which is much faster than writing data to, or reading data, from external RAM.
All of the Apple-supplied applications run faster than their Leopard counterparts. While not earth-shatteringly faster, the speed increase is noticeable. As third-party applications are released in 64-bit versions, speed increases should be seen across the board.
The other place I noticed speed increases is when starting up and shutting down. Both actions seem lightning-fast compared to Leopard, so much faster that I no longer find myself waiting around for my Mac to boot. If you leave your Mac on 24/7 because you hate waiting for it to boot, you can now seriously considering turning it off when you’re not using it, to save a little energy.
Snow Leopard Review: The Rough Edges
Snow Leopard uses a new way of dealing with printers and printer drivers during installation. Instead of installing a long list of printer drivers, Snow Leopard saves space by only installing drivers for printers it detects during the installation process.
Sounds good, right? Well, not really. Snow Leopard only detects local printers connected via USB, or network printers that use Bonjour to advertise that they’re on the network. If your printer doesn’t meet these requirements, Snow Leopard won’t install drivers for it.
Snow Leopard was designed as an upgrade, so why can’t it look at the printers that are currently installed and automatically install and configure for the same printers? Some of us have network printers that don’t use Bonjour, and some of us use printer drivers that aren’t the default drivers for our printer models. Snow Leopard ignores these possibilities, and instead installs and configures printers the way it wants to. If this happens to you, you’ll have to uninstall the printers and reinstall the drivers you want.
Another rough edge is startup items, or the lack thereof. Snow Leopard removes all startup/login items during installation. This makes sense, because historically, these items caused many upgrades to fail. But it would be nice if Snow Leopard would tell us what it’s doing, perhaps by creating a folder or list of removed items, so we would know what to put back.
Finally, none of my third-party screen savers work. Yes, I know they need to be rewritten as a 64-bit service, but I’m afraid many will never be updated, and I am not amused.
Snow Leopard Review: Conclusion
Apple used Snow Leopard as an opportunity to break with the past, leaving PowerPC Macs behind and embracing an Intel future with open arms. This determination to move Mac users and Apple developers to an Intel 64-bit architecture is underscored by Apple’s decision to not only offer the upgrade at just $29, but also to omit any upgrade-qualification-checking mechanism, which means that even if you have an early model Intel Mac running Tiger, you can move up to Snow Leopard.
Overall, Snow Leopard is fast, sleek, and lean. Although it does have a few minor annoyances, I find it easy to recommend Snow Leopard to anyone who has the appropriate hardware. After all, for $29, how can you really go wrong? If you’re upgrading from Tiger, you’ll find Snow Leopard has lots of new features after all, because it includes all the whiz-bang stuff that was new in Leopard.