Re:86Box: Why Not Pentium III?
by captainmuon on Friday April 08, 2022 @07:50AM
(#30955791)
What about old versions of VirtualBox? As far as I understand, VirtualBox originally used some kind of dynamic recompilation to run on hosts without modern virtualization (like VT-D). It used to run most instructions directly on the host CPU, emulating only certain ones. I think they removed it at some point, though. Is it not accurate enough? I remember it used to run OS-X much better than other virtualizers.
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I'm not sure why this was ever dropped, if I remember right back in the early 2010s, this ran XP very usable on a C2D XP laptop. Pretty sure I even got 7 working at some point, the only real limit was that it absolutely could not run 64 bit vms.
It's because dynamic recompilation as done in VirtualBox & QEmu is on the order of 10x slower than CPU accelerated/supported virtualization. You don't notice that (as much) with DOS or a simple Windows 9x VM. But you will notice that if you're running busy SQLServer, ISS, .Net, Linux, PostgreSQL, MySQL Servers.
Re:86Box: Why Not Pentium III?
by shadowofneptune on Friday April 08, 2022 @09:40AM
(#30956650)
I pulled out my version of 86Box to check, and it does have mandatory dynamic recompilation if you try to emulate later chips.