You don’t hear much about code overlays today. With today’s seemingly unlimited virtual memory in desktops and servers, applications often don’t check for the risk of running out of memory. Yet in the early days of the mainframe’s using core memory and the fledgling IBM PC, running out of memory was a frequent concern. Overlays were instrumental in doing more with less.
Overlays continue to have a role today in microcontrollers because of those products’ own memory limits. Embedded products may begin with a selected microcontroller, only to discover later that the software won’t fit. If this happens ...
