使用户实体能够注册（例如标识用户本身、注册目的以及进入时间）的一种装置，并能和相应的数据一起注销，以便配合操作系统办理适当的记帐手续。

A device that enables a user entity to log in, for example, to identify itself, its purpose and the time of entry; and to log out with the corresponding data so that the appropriate accounting procedures may be carried out in accordance with the operating system.