1. A medical device customization system comprising: a medical device comprising: hardware comprising: a biological probe; a memory; and a processing unit to receive signals from the biological probe and to store data in the memory based on signals from the biological probe; and a virtual machine manager establishing: a base application virtual machine to process signals from the biological probe and store base data in the memory; and a custom application virtual machine for carrying out a custom application using the base data stored by the base application virtual machine in the memory, wherein the code directs the processing unit to determine the authority level based on an encrypted authorization key received from the custom application virtual machine.