Nowadays by means of state-of-the-art implementations and arrangements persons are allowed to simplify and brighten up their existing like never before. Pocket digital assistant, as well referred to as apps for iphone, is one of these arrangements. PDA is a pure computer that’s why it does not have the functions of the telephone. Playing video files, audio files, being used as an organizer, operating with word processors and some other types of useful software are the features of it. Thus if you are a kind of an active individual that doesn’t want to lose their time while journeys, the PDA would be surely handy for you. You can watch a film, look through a magazine or play games with the suitable free windows mobile software at the time of long trips. Agree that to have by you a fat magazine is a bit inconvenient. Bearing in memory that the PDA can contain more than one book, the device becomes very much valuable. Taking into account that the arrangement is multitasking, you may listen to audio while reading a magazine. Lots of people are also concerned in Mobile themes, so they may easily obtain it online.The OS (operational system) is the necessary part of each PDA. Selecting a PDA you need to adopt a decision about its operational system: PalmOS, Microsoft Windows Mobile or Linux. The plus of Linux is that it has free programs, but ordinary clients are more familiar with Windows. PalmOS has been especially created for the PDA that’s why it’s simple to operate but if you use a number of programs simultaneously there can be faults. After you have clarified what OS satisfies you, you need to take into account more substantial points, such as the input medium, computer horsepower, volumes of permanent memory and working memory, screen size and the possibility of extending the memory.Energy demand is the challenge of every PDA. Currently, producers cannot achieve excellent effects in this sphere.