Over the last few weeks I’ve been touting the many mostly evolutionary, but some bordering on revolutionary, new features in Mac OS 10.4 “Tiger”. This week we’re talking graphics – that is, how Tiger manages the processing and presenting of what you see on your monitor. Tiger’s new “graphics engine” is made up of four parts: three system-level software “packages” (Core Image, Core Video and QuickTime 7), and your Mac’s graphics card (henceforth referred to as the GPU, or Graphics Processing Unit). Before we go any deeper, let’s program the “way back machine” to visit the early days of computer graphics.

Almost 20 years ago, IBM created the VGA (Video Graphics Array) standard that gave monitors the ability to display a whopping 256 colors. Then along came SVGA, or Super VGA, with the capability to display 16.8 million colors. In those days, video processing chores were handled by the computer’s main processor (or CPU, Central Processing Unit), and any memory needed came from the system RAM (Random Access Memory). As operating systems and their GUIs (Graphical User Interfaces) became more visually sophisticated, graphics demands began to affect overall system performance - hence the move to a dedicated GPU to handle the load.

Unless, of course, you’re saving money with a Dell “internet special” PC. Look real close at the system specifications of these “multimedia powerhouses”, and you’ll see listed under “Graphics Card” something called “Integrated Intel Graphics”. Unfortunately, this is just Intel doublespeak for “no dedicated GPU”, as Integrated Intel Graphics really means that portions of the computer’s CPU speed and RAM are used to generate graphics on the monitor. Sounds like 20 years ago? You bet. No matter how the maker labels it, Integrated Intel Graphics is yesterday’s technology brought direct to you from the computer sweatshops of today. You get what you pay for. But, I digress.

Now, let’s program our “way back machine” to go “back to the future”. All Macs (including laptops) have, for some time, shipped with GPUs. A GPU has two parts: the processor (similar to the CPU in a computer), and dedicated video RAM. As a general rule, the more RAM, the more capable the GPU. Today’s GPUs can process more than 6 billion pixels (the building blocks of images on your computer monitor) per second, and GPU performance rates are doubling every six months.

Apple is ready to put this performance to good use. Built into Tiger are two technologies, dubbed Core Image and Core Video, which represent a major change in how an operating system interacts with the GPU. (You guessed it, Tiger also uses Core Audio, but that’s another story). Core Image and Core Video delegate graphics-intensive tasks to the GPU, freeing up the Mac’s CPU and RAM to get on with the business of computing. Besides powering “eye candy” like Tiger’s hovering-above-the-opaque-desktop Dashboard widgets, Core Image can also perform hundreds of modifications, in real time, to any image. Core Video can do much the same to video – all without tasking (and therefore taxing) the CPU. Tiger just scratches the surface of this technology, and developers are hard at work building applications to take advantage of it.

The last part of Tiger’s graphics engine is QuickTime 7. Most users know QuickTime as the Mac’s video player. However, QuickTime is really the operating system’s “media layer”. Whether you are listening to music with iTunes, or editing your home movies with iMovie, or creating your own music with GarageBand, or even editing a photo in iPhoto, QuickTime is at work behind the scenes. More on QuickTime 7 next time.

© 2005 Peter F. Zimowski