Portable memory device and method of securing the integrity of stored data therein utilizing a starting address and a stored memory cycle number

A portable memory device, comprising:

• a memory having a plurality of storage locations which are sequentially addressable and into which input data is writable and from which output data is readable, the plurality of storage locations including a preselected range of storage locations with a set of addresses extending from a first address to a last address;
• and
• a processor for storing a starting address in the memory corresponding to a memory address between the first address and the last address and for writing input data into the memory only within the preselected range of storage locations by sequentially addressing the memory from the starting address in a memory cycle, wherein a new memory cycle is started each time the starting address is the first address, and wherein the processor stores a current memory cycle number in the memory and increments the stored memory cycle number for each new memory cycle;
• and
• wherein the processor outputs the stored memory cycle number with the output data read from the preselected range of storage locations, whereby each location in the preselected range of storage locations has a memory cycle number associated with the data stored therein to indicate if an overwrite and therefore a loss in the integrity of the data has occurred.

A control process comprising the steps of:

• moving a portable memory device from one station to at least one other station;
• transmitting input data from a station to the portable memory device for storage therein;
• receiving output data from the portable memory device at a station;
• and
• securing the integrity of data stored in the portable memory device by
• providing a memory in the portable memory device having a plurality of storage locations which are sequentially addressable and into which input data is writable and from which output data is readable;
• preselecting a range of storage locations with a set of addresses extending from a first address to a last address;
• storing a starting address in the memory corresponding to a memory address between the first address and the last address;
• writing the input data into the memory only within the preselected range of storage locations by sequentially addressing the memory from the starting address, a new memory cycle being started each time the starting address is the first address;
• storing a current memory cycle number in the memory;
• incrementing the stored memory cycle number for each new memory cycle;
• and
• outputting the stored memory cycle number with the output data read from the preselected range of storage locations, whereby each location in the preselected range of storage locations has a memory cycle number associated with the data stored therein to indicate if an overwrite and therefore a loss in the integrity of the data has occurred.