subset of the components found in a personal computer fig1 illustrates a standard laptop computer 3 fig2 illustrates the computer 3 in schematic form and lists several of the internal components of the computer 3 in addition fig2 illustrates one form of the invention 5 including several components 6 which are added to the computer 3 device 5 will be designated a pda herein various embodiments of the invention utilize different combinations of the added components 6 the added components include an infra red communication link 7 which preferably complies with the standard designated irda irda is an acronym for infra red developers association which is known in the art this link 7 is used to transfer data to an external device as explained below the invention adds programming indicated as block 15 which performs the tasks described below and described in the flow charts illustrated in the drawings in this form of the invention a digital document indicated as block 17 is stored in memory 20 that document 17 may contain a photograph of the owner of the pda 5 or other protected information in this example the part of memory 20 storing the document 17 is a special type it cannot be altered that is the memory 20 is of the read only type so that the document 17 cannot be modified such non writable memory is commonly used in computers for example the bios basic input output system used in the personal computer is frequently non writable as another example an.