> ----- Original Message ----- > From: "Paul Koning" <paulkon...@comcast.net> > To: "General Discussion: On-Topic and Off-Topic Posts" <cctalk@classiccmp.org> > Sent: Friday, 11 September, 2015 4:58:41 PM
> I agree. You can use overlays on any hardware platform that has random > access secondary storage. > You need it if your programs are larger than your primary memory. … Overlays were also commonly used on Mag Tape systems before disk became common. The George 1 and 2 operating systems for the ICL1900 series (and many compilers) came in both disk overlaid and tape overlaid versions (e.g. the Fortran compiler XFAE was disk overlaid, XFAM was tape overlaid but otherwise identical - both were designed for 16K word systems allowing about 3K for Exec and the "run-time" overlay of George.) Andy