I guess the first 640KB was at 0-9FFFF, but where was the other 384KB mapped?
These were around before DOS had HIMEM.SYS etc.
It seems a waste to have RAM at A0000-FFFFF, but I seem to remember that these computers had extensive shadowing, so maybe 0C0000-11FFFF?
Or was this a configurable option?
How was it implemented? I always assumed it was done using hardware gating.
These were around before DOS had HIMEM.SYS etc.
It seems a waste to have RAM at A0000-FFFFF, but I seem to remember that these computers had extensive shadowing, so maybe 0C0000-11FFFF?
Or was this a configurable option?
How was it implemented? I always assumed it was done using hardware gating.
Last edited: