People who work on buildings,electrical oolewor other difficult-to-climb places may be equipped with a special form of mobile wireless computing device called a wearable device.These devices come in a variety of forms, including wrist devices, small screens worn close to the eyes, voice activated equipment, and keyboards built into gloves or clothing. For an expanded description of these devices and a history of their development, see en.wikipedic.org/wiki/weareble_romputing. Glaciercompuleccose, kap in.com, and Isse.com manufacture a variety of wearable computers. Examples can be viewed on their Web saes,
There are three dominant PC operating systems (OSs): Microsoft Windom, Apple, and Linux. Most laptops and related devices are peer,ed by these OS, Programmers who write, software apps target one or more of these platforms for their programs. Writing apps for handholds is more difficult because there are more than twice as many systems to write for. Here is a brief summary of the most popular mobile OSs: