Dynamic link library integrity checking for handheld medical devices

A method of checking the integrity of a shared file that is called by an application being executed on a handheld medical device and that is callable by one or more other applications that are executable on the handheld medical device, the method comprising:

• loading the file from nonvolatile memory to a volatile memory beginning at a fixed location in the volatile memory,
• the shared file including a first routine for performing a function of the handheld medical device and including a second routine for performing an error detection function on the shared file once the shared file is loaded to the volatile memory;
• selectively executing the first routine from the volatile memory to perform the function;
• selectively executing the second routine from the volatile memory including:
• selectively calculating an error detection value based on the shared file;
• comparing the error detection value with a predetermined value set for the error detection function;
• and
• generating an output indicating that an error is present when the error detection value is different than the predetermined value.

A method of preparing a dynamic link library (dll) file for execution by an application on a handheld medical device, the application loading the DLL from a read only memory (ROM) of the handheld medical device to a random access memory (RAM) of the handheld device beginning at a fixed location of the RAM before execution, the method comprising:

• compiling, at a remote computer, the DLL based on code generated based on user input,
• the DLL including a first routine for performing a safety critical function of the handheld medical device and including a second routine for a performing a cyclical redundancy check (CRC) on identified portions of the DLL;
• calculating, at the remote computer, a check value based on the identified portions of the DLL;
• and
• selectively setting, at the remote computer, a predetermined value in the DLL to the check value,
• wherein the performance of the CRC using the handheld medical device includes calculating a second check value based on the identified portions of the DLL once the DLL is loaded to the RAM and comparing the second check value with the predetermined value.