Can anyone explain gBehaviorsArray from ImgGallery demo?

Question

It's in gallery.js is the Spry demos. I'm having a hard time dissecting this: it looks like it's taking itself as a paramater of a "finish: function()", and then going into some sensible code, but then I'm trying to figure out where we're getting gBehavioursArray.start()? this function was never defined.
gBehaviorsArray["mainImage"] = new Spry.Effect.Opacity(img, Spry.Effect.getOpacity(img), 0, { duration: 400,           finish: function()           {                gBehaviorsArray["mainImage"] = new Spry.Effect.Size(img.parentNode, Spry.Effect.getDimensions(img.parentNode), { width: width, height: height, units:"px"}, {duration: 400,                     finish: function()                     {                          // Use an image loader to make sure we only fade in the new image after                          // it is completely loaded.                          gImageLoader = new Image();                          gImageLoader.onload = function()                          {                               img.src = gImageLoader.src;                               gImageLoader = null;                               gBehaviorsArray["mainImage"] = new Spry.Effect.Opacity(img, 0, 1, { duration: 400,                                    finish: function()                                    {                                         gBehaviorsArray["mainImage"] = null;                                                                                  // Our new image is fully visible now. Remove any opacity related                                         // style properties on the img to workaround the IE bug that creates                                         // white dots/holes in the images. Removing the properties forces                                         // IE to re-render the image correctly.                                         img.style.opacity = "";                                         img.style.filter = "";                                         // If the slide show is on, fire off the timer for the next image.                                         if (gSlideShowOn)                                              SetSlideShowTimer();                                    }});                               gBehaviorsArray["mainImage"].start();                          };                          gImageLoader.src = imgPath;                     }             });             gBehaviorsArray["mainImage"].start();           }      });      gBehaviorsArray["mainImage"].start();

Answer 1

Processor speed by Mhz doesn't really indicate how fast a machine in. The Mhz myth is as true as it ever was. What really makes a difference in the speed of the machine is software, and the speed of your hard drive, and the amount of time the machine spends processing on the hard drive versus the physical RAM. If there is parallel processing across cores in the processor, that helps for those tasks that take advantage of it. http://www.everymac.com/ is good about telling you the exact processor model used on each Mac. You can then look at Intel's specs about those processors to determine how many cores, bus speed, the machine uses. The website:
http://www.barefeats.com/
is a good benchmark website, but note that benchmarks may vary according to configuration, quality of RAM, access times on the hard drive, access to optical drive, energy saver power settings, etc...