Been looking everywhere for answers to these questions. I am finishing a project running MS-DOS 6.22 on VirtualBox and I am stumped on these questions. Any help please???

What is the largest Hard Drive volume this release of DOS can use?
Why does this release of DOS have that particular upper limit to disk storage?
Does this release of DOS support virtual memory?
How can you force a program or program group to "run real"? What is the advantage of "running real"?
How much physical memory is reserved to the operating system? Where in memory does DOS run.

Please & thank you