Our crystal ball was a little hazy back in 2008 when we introduced an expansion under 004.16 Personal computers (004.167) and made its caption Handheld computing devices. We were thinking that size would be the defining element that separated this new class from other personal computers. On the basis of size—indeed, the size that could be comfortably held in one hand—we restricted the use of 004.167 Handheld computing devices to the likes of smart phones, personal digital assistants (PDAs), palmtop computers, and pocket computers, while 004.16 Personal computers retained tablets, notebook computers, and laptops. But, alas, it did not take long before questions started to arise. Shouldn’t tablets be in 004.167? Well, what about phablets? Clearly classifiers’ intuitions drew the line between 004.16 and 004.167 in a different place than what had been set out in the DDC itself. A mere handful of years later--i.e., NOW--the defining element for the re-captioned 004.167 Mobile computing devices is portability (which, of course, is related to size, but provides a more pragmatic dividing line). So the question is no longer whether the device can be comfortably held in one hand, but can it be easily carried from one location to another. Being mobile also implies the use of wireless technologies. Redefining the dividing line between 004.16 and 004.167 means that all of the following are now part of 004.167 (in addition to the devices that were part of 004.167 to start with): e-book readers, phablets, tablets, (most) laptops, notebooks, wearable computers. In theory, the dividing line is still somewhat a fine one. A laptop that is a desktop replacement should be classed in 004.16; alternatively, any laptop that is merely “luggable” should be classed in 004.16. Only laptops that are truly mobile (but this applies to most laptops today) should be classed in 004.167. However, since we don’t find literature in WorldCat for desktop replacement laptops, the fine-dividing-line issue appears to be moot.
Here are examples of 004.16 devices:
Here are examples of 004.167 devices:
Attribution for 004.16 device images (in left-to-right order):
Attribution for 004.167 device images (in left-to-right, top-to-bottom order):