Switching to the Mac: The Missing Manual, Yosemite Edition

OS X and Security

OS X has a spectacular reputation for stability and security. At this writing, there still hasn’t been a single widespread OS X virus. There’s also no Windows-esque plague of spyware (downloaded programs that do something sneaky behind your back).

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 8 percent market share?”

That may be part of the reason OS X is virus-free. But OS X was also 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:

• OS X has always come from the factory with all of its ports shut and locked.

  POWER USERS’ CLINIC: Virtual Memory, Security, and You

  Virtual memory is a trick that computers use to keep a lot of programs open at once—more, in fact, than they technically have enough memory (RAM) for. How do they manage to keep so many software balls in the air? Easy: They set some of them down on the hard drive.

  When you bring Photoshop to the front, OS X frees up the necessary memory for it by storing some of the background programs’ code on the hard drive. When you switch back to, say, Safari, OS X swaps Photoshop for the Safari code it needs from the hard drive, so that the frontmost program always has full command of your actual memory.

  Sophisticated software snoopers could, in theory, sneak up to the Mac while you’re logged in but away from your desk. Using ...