Canalys is still staking its market share estimates on the view that mobile tablets are as relevant to PC market share as desktops and laptops. If we accept that interpretation, Apple was easily on top of the heap during the fourth quarter. Combining iPads and Macs would give it 27 million computer shipments in the fall, or 20.1 percent of the 134 million computers that left factories -- the first time it would have had more than a fifth of the market. Not that Apple was the only one having a good tim
