On 06/03/2020 03.24, James Knott wrote:
On 2020-03-05 04:48 PM, Anton Aylward wrote:
Nonsense! "Virtual memory means virtual performance" was the idiom from the 1960s when IBM and others fist implemented virtual memory with little understanding for the algorithms! Back the a IBM/370 with 256K of memory was typical. Linux is more sophisticated and can always use the memory, somehow.
My first experience with virtual memory was with DEC VAX 11/780 systems. Prior to that, we had overlays, where portions of code were swapped into memory. This was used with head per track disks.
I used overlays with MsDOS. Actually, a library of the compiler. At some point, we could create ramdisks with the memory beyond the first megabyte, that the system and programs could not use, and copy the overlay there. That was *fast* :-D -- Cheers / Saludos, Carlos E. R. (from 15.1 x86_64 at Telcontar)