which is a high level block diagram of a storage device 210 constructed according to a preferred embodiment of the present invention storage device 210 is permanently or removably connected to host 105 for data exchange similarly to how prior art storage device 110 is connected to host 105 in fig1 a user storage area 220 contains user files 122 and service files 124 similarly to user storage area 120 of fig1 user storage area 220 also contains compulsory files 226 a display 104 is optional for displaying data from a device storage area 230 such as a user identification under the control of controller 100 preferably display 104 uses an u201c electric paper u201d i e a screen that retains its displayed content upon power cutoff as described for example in u s pat no 5 389 945 to sheridon which patent is incorporated by reference for all purposes as if fully set forth herein compulsory files 226 are conventionally accessible to host 105 via the operating system and the file system of host 105 the operating system and the file system of host 105 may be loaded from user files 122 and service files 124 or alternatively from another storage device not shown that is connected to host 105 examples of compulsory files 226 include an autorun program file that runs automatically upon storage device 210 being turned on or connected to host 105 an application program that resides in the root directory of storage device 210 and a document file that has an eye catching icon and that appears e g according to the windows u2122 operating system under the u201c my documents u201d folder it is the.