HP Forums
emulated or virtual? - Printable Version

+- HP Forums (https://archived.hpcalc.org/museumforum)
+-- Forum: HP Museum Forums (https://archived.hpcalc.org/museumforum/forum-1.html)
+--- Forum: Old HP Forum Archives (https://archived.hpcalc.org/museumforum/forum-2.html)
+--- Thread: emulated or virtual? (/thread-243434.html)

emulated or virtual? - Mike (Stgt) - 05-13-2013

A nice finding from an other list I'd like to share with the emulator adicted here:

Does this run on the CPU or on the blades? (Beware; some pedants insist on distinguishing the terms "emulated" and "virtual".)

(Subject was z86VM)


Re: emulated or virtual? - bhtooefr - 05-13-2013

In that case, there is a huge difference between emulation and virtualization.

Emulation is emulation of the entire system including CPU (which z86VM appears to do, emulating an x86 CPU on an ESA/390 ARCHLVL2 CPU), virtualization is emulation of the peripherals but not the CPU (by trapping calls to I/O devices and such, along with some trickery to make privilege levels work right, and emulating that).

Re: emulated or virtual? - Mike (Stgt) - 05-14-2013

Realy? But - I assume you know z/VM or VM/ESA - there I may define virtual CPUs just to test MP systems without having one. And if I have a program that runs the OS of an HP41, is that an emulator?


Re: emulated or virtual? - bhtooefr - 05-14-2013

VM (no matter the version, all the way back to CP-40/CMS) is virtualizing - code directly runs on the native CPU, but I/O is trapped and emulated.

And, yes, programs to run the HP-41 OS are emulators. They're emulating the CPU.

Re: emulated or virtual? - Mike (Stgt) - 05-14-2013

I see, you are one of those who clarly distinct between 'emulated' and 'virtual'. With the time I have adopted an other point of view: My program "emulating" a Nut-CPU (for HP41 and all Voyagers) is just a firmware-interpreter. Even Eric Smith calls his 2nd to none Nonpareil 'a simulation'.


BTW: There are emulators out there, Emu71, Emu42, Emu48, to name just a few. ;)

Re: emulated or virtual? - bhtooefr - 05-14-2013

Emulation vs. simulation is a fuzzier line, although I've occasionally heard simulation being used to describe transistor-level emulation.

(Simulation in that sense is very rare except during development of hardware, although there is a 6502 emulator that is transistor-level: http://visual6502.org/)

As far as I know, Nonpareil definitely isn't doing that, but like I said, the emu vs. sim line is far more blurred, and sometimes simulator is used as a synonym of emulator.

Re: emulated or virtual? - Mike (Stgt) - 05-14-2013

"... and virtual _is_ real."

(Paradigm – George Clinton featuring Prince, on 'How Late Do U Have 2BB4UR Absent?')

Ciao.....Mike ;)