I have installed MS-DOS 6.22 (released in 1994) on Virtual Box, and I want to know if Virtual Box is emulating an ISA bus or a PCI bus. The settings for my virtual machine don't show any information about the bus.

  • 5
    All PCs have what looks to software to be an ISA bus. Modern PCs without a physical ISA bus use the LPC bus instead to connect ISA compatible devices like serial ports and a PS/2 keyboard/mouse controller (usually provided by a single Super I/O chip). Software running on a real PC can't really tell the difference between a device on an ISA bus from the same device on a LPC bus so it doesn't really matter whether a virtual machine emulating a PC emulates an ISA or LPC bus. Both look the same to software, so for all intents and purposes all VMs have an ISA bus.
    – user722
    Jun 7, 2017 at 21:26
  • 1
    And now even the LPC bus is being obsoleted, by eSPI... Jun 7, 2017 at 22:03
  • @Ross Ridge that sounds like an answer, and a correct one at that. Aug 18, 2017 at 21:26

1 Answer 1


If you went with VirtualBox's default settings for an MS-DOS system, you've got both: an Intel 440FX northbridge providing a PCI bus, and an Intel PIIX3 southbridge connected to that bus, providing an ISA bus. The virtual video card (generic VESA-compatible) and PCnet-FAST III network card will be attached to the PCI bus. The sound card (a virtualized SoundBlaster 16) will be attached to the ISA bus. The hard drive and CD-ROM will be on a PIIX4 connected to the PCI bus.

(Source: attaching a SysRescueCD to an MS-DOS VM and seeing what the diagnostics had to say.)


Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.