Appendix G: Advanced Programming and Operation261
However, there are a few things that must be considered before you attempt a COPY . The applications program on the application module must be able to fit into program memory. If it does not you will not be able to execute a successful COPY . Here is what happens when you execute COPY and specify a program name:
  1. The calculator first searches for the specified name. If it is not found (it is misspelled, or the application module is not in place) the display will show NONEXISTENT.
  2. The HP-41C then determines the length of the specified program.
  3. The size of unused program memory is determined.
  4. If the unused portion of program memory is large enough to accept the entire application program, the program is copied into program memory.
  5. In the event that there is not enough room in program memory to hold the entire application program, the HP-41C will pack program memory (packing is explained in section 8). You will momentarily see PACKING in the display.
  6. The calculator will then ask to reenter the COPY function with the TRY AGAIN display.
  7. If the unused portion of program memory is now large enough to hold the entire application program, the program will be copied into program memory. If the unused portion of program memory is still not large enough to hold the application program, the calculator will again pack (PACKING) and asks you to TRY AGAIN.
  8. At this point, you should clear program instructions out of program memory to make room for the application program. If you continue to execute COPY when there is not enough room in program memory to hold the desired program, the HP-41C will continue to pack program memory while displaying PACKING , and ask you to TRY AGAIN.
Attempting to COPY a program from program memory to another location in program memory will result in the RAM message (RAM means Random Access Memory—these are the storage registers that you can store data and program instructions into). Attempting to DEL , CLP ,    , or insert into a program that is currently in an application module will result in the ROM display (ROM means Read Only Memory—this is what application modules are stored in).
You may copy the application module program to which the calculator is presently positioned by not specifying a program to which the calculator is presently positioned by not specifying a program name. For example, COPY ALPHA ALPHA copies the application module program that the calculator is currently positioned to into program memory.