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virtual-machineemulationvmwarevirtualizationhypervisor

Could we fake processor and RAM with hypervisor?


I hear a lot about "Hypervisors are not emulators. If you need to emulate another hardware specifications than you computer have, you need to use emulator, not hypervisor".

Well, but yesterday I saw this video on youtube - click here - which shows how to install Win 95 on modern macOS with VMware Fusion.

The strange thing for me is that on 17:39 you could see that Win 95 virtual machine is "Pentium Pro with 64 MB RAM".

enter image description here

Hmm! So, Fusion somehow faked processor and RAM, right? But it is not emulator, right? So, does it mean that any hypervisor can fake processor and RAM?


Solution

  • At the time of its release, Windows 95 only had code to recognize CPUIDs up to Pentium Pro. Any processor not lower than Pentium Pro is "called" Pentium Pro.

    The main difference is the Hypervisor cannot emulate CPU code. All code must run on the original processor.

    The hypervisor does emulate the BIOS, which in tells the OS the hardware specs available; including RAM, Boot order and peripherals attached.