Gartner and IDC last week (Oct. 9) released their measurements of the PC industry. The dueling giant research firms have never agreed on the exact number. If they did, one of them would become instantly redundant, but they are close enough. IDC's count at 81.61 million is 1.7 percent higher than Gartner's 80.28 million units worldwide. However, each firm took a slightly different slant on its counts.