There are ways around this in some cases: use emulation, modify the existing program to port it to the new system (if the source code is available), or write a

There are ways around this in some cases: use emulation, modify the existing program to port it to the new system (if the source code is available), or write a new one. An ideal system will allow all three possibilities; although, which are possible also depends on the specific program that you want to run.