Don Maslin/Archiving system software

On 18 Mar 2007 at 22:46, Lyle Bickley wrote: 3.1x, early Lyle, that's not what I said. I said "a computer from today can run software written 40 years ago--and generally, much faster." I said nothing about running under one OS or another. To say that running older software on newer machines isn't possible is pretty much equivalent to saying that a new machine isn't Turing- complete. I can emulate (with whatever software necessary) cycle-for- cycle operation of an older machine. Maybe not as fast as the original (depending on the complexity of the emulation)--which is why I added "generally much faster". I can readily appreciate that I/O devices may well represent a really tough nut to crack, but given a free reign on abstraction, it can probably be done in some fashion (e.g. a disk file instead of a tape file). And the reverse is quite true. I can emulate an IA64 architecture on a 2MHz Z80, given sufficient storage and time. Not fast (or cheap), but I can do the emulation. To say that it's not possible would again be equvalent to saying that the Z80 isn't Turing-complete. Cheers, Chuck