The first limit you can hit is the RAM limit, and (last time I ran into it), it was very low -- only about 4MB. That was about 10 years ago, under KSS 8.3. This is not a physical RAM limit -- adding more RAM does not improve this situation. It's a limit inherent to something in VxWorks/KSS.
Briefly: The KRC runs everything from RAM. The HDD contents are loaded into the RAM drive during boot, but all execution and edits are made in the RAM drive, with periodic or event-driven writes from the RAM drive to the HDD.
The only way (so far) to get around the RAM limit is to use the DirLoader and "swap" program modules in/out of the RAM drive.
Thanks for the information, and how does DirLoader work? Could you clarify this for me?