virtualbox.org

I learned the following the hard way: for those who are trying to install Linux on Windows XP or another "older" OS on a computer with physical memory size 1 GB or less (which is now considered small), only special tiny versions of Linux will work.

An example is CorePlus-current.iso (only 76 MB), which can be downloaded from http://distro.ibiblio.org/tinycorelinux/downloads.html and other websites. This OS will run in 256 MB of memory under VirtualBox. I was able to install and run two different browsers in the guest OS (Core Plus), all from within the guest. Of course, they both ran slowly, but they appeared to run correctly.

And, of course, it is possible create a VM that contains MS-DOS 6 and Windows 3.1 under VirtualBox running on an XP with a small memory.

But for practical and up-to-speed execution of most OSes under VirtualBox, I recommend that the host be a "modern" computer and OS.

IMHO, the practical minimum spec for any host is 2GB RAM, dual core processor (with VT-x), and 200GB free disk space. On such a host you can run XP as the host and XP as the guest, quite happily: the guest being assigned one core and 512MB RAM, 32GB hdd.

Such a spec would be a tight fit if the host OS was (say) Win7-64bit. I'd like to see 4GB RAM on such a host.