it is not uncommon for two or more wireless - enabled devices to spend most of their time in close proximity to one another . for example , a person may routinely carry a personal digital assistant and a portable digital audio / video player , or a cellphone and a pda , or a smartphone and a gaming device . when it is desirable to increase the memory storage capacity of a first such device , it may be possible to use memory on one or more of the other devices to temporarily store data from the first device .