Can my computer use Mac OS X?

The computers that can use Mac OS X are any computer that Apple shipped with a G3 processor except for the very first PowerBook G3. That covers prety much everything Apple has shipped since 1997. You may wonder if just having a G3 processor is sufficient. For example, if you upgraded your pre-G3 Power Mac with a G3 upgrade card, would you meet the minimum requirements?

Although Apple uses the presence of the G3 processor as the measure of which of its computers can use Mac OS X, it's not only the processor that is significant. In order for an operating system to work on a particular computer, that operating system must contain instructions for how to work with each specific kind of chip in the computer. Remember that the main processor is only one chip of many. There are other chips that control the hard drive, expansion slots (such as NuBus, PCI or PCMCIA), ports (ADB, USB, SCSI, serial) and so on. Even for computers that have all of the same ports in common, there may be different chips that run those ports. This is why having a G3 upgrade card isn't enough for you to run Mac OS X.

Can I use my applications with Mac OS X?

Normally applications have to be rewritten (or at least recompiled by their developer) to run on new operating systems. This would require you to update every single application you have. Not many users would be willing or able to do this. So, Apple has provided a way that you can run applications unmodified. These applications run using the "Classic" envrionment. Although most applications run just fine, utilities (especially extensions and control panels) may not work as expected or at all. Check with your appilcation manufacturer to be sure.

However, you can't expect to realize the benefits of Mac OS X with applications that weren't originally written when Mac OS X was available. Classic applications can be altered without having to be totally rewritten from scratch.

Can I use my devices with Mac OS X?

All devices need software drivers to run under a particular operating system. Drivers work at a lower level, closer to the specific hardware that's in a machine. Therefore, they more often need to be changed when hardware or the operating system changes (whereas applications can continue to work for years, if they are simple or well-written to begin with). Some drivers are built-in to the operating system. Some aren't. Apple includes some basic drivers in the operating system that support some kinds (classes) of hardware products. These are called class drivers.

Apple includes class drivers for USB Mass Storage (devices like hard drives, removable drives (floppy, Zip, Jaz, SuperDisk)), USB Human Interface Device (HID, devices like mice, keyboards, joysticks and so on), FireWire mass storage.

Look for your devices on Apple's list of Mac OS X-compatible devices. Also check with your devices manufacturer.