By the beginning of 2005, Mac OS X already had a spectacular reputation for stability and security. Not a single Mac OS X virus had emerged—a spectacular feature that makes Windows look like a waste of time. There's no Windows-esque plague of spyware, either (downloaded programs that do something sneaky behind your back). In fact, there isn't any Mac spyware.
The usual rap is, "Well, that's because Windows is a much bigger target. What virus writer is going to waste his time on a computer with five percent market share?"
That may be part of the reason Mac OS X is virus-free. But Mac OS X has also been built more intelligently from the ground up. Listed below are a few of the many drafty corners of a typical operating system that Apple has solidly plugged:
The original Windows XP came with five of its ports open. Mac OS X has always come with all of them shut and locked. (Ports are back-door channels to the Internet: one for instant-messaging, one for Windows XP's remote-control feature and so on.) These ports are precisely what permitted viruses like Blaster to infiltrate millions of PCs. Microsoft didn't close those ports until the Windows XP Service Pack 2.
When a program tries to install itself in Mac OS X, a dialog box interrupts your work and asks you permission for that installation. In fact, it requires your account password. (Windows XP goes ahead and installs it, potentially without your awareness.) In Tiger, you can expand the dialog box to see ...