Running BSDi BSD/OS on VirtualBox

By default, the BSD/OS kernel recognises the CPU of a VirtualBox guest VM as a Pentium II. The kernel is able to boot correctly but performing any I/O results in failure due to memory errors. Adjusting the CPU mask of the VM from the host resolves this issue.

Note the name or GUID of the VM to be modified
% VBoxManage list vms
"BSDi BSD/OS" {36772f8c-ec06-4f37-a995-662fc38ad103}

Adjust the CPU of the VM
VBoxManage modifyvm "BSDi BSD/OS" --cpuidset 1 0x4a7 0x7100800 0x17bae3ff 0xbfebfbff

Obtained from OS2 Museum.