I have a Bridgeport BOSS that I converted to Centroid controls. It
runs a version of Linux from a very small solid state hard drive.
Works fine. Centroid system started out as a Windows OS. Changed
over to the Linux OS when it became available.

Don't know about the dual boot. Don't know why you would need it.
Linux runs everything on my machine including the programming software
and the machine itself.

You can run a lot of DOS applications in Dosbox (can be installed by the
command sudo aptitude install dosbox).
Yes, you can dual boot DOS and Linux also. Make a DOS partition (FAT32)
(partition C), you can easily install Freedos or MS-DOS on it and then install
Ubuntu or other Linux on the remaining space by selecting the option "guided-use
largest available free space".
Then it is very easy to access your DOS partition under Linux and copy there
whataver files or programs you need, you can also download DOS programs from the
Internet easily under Linux and place them on the DOS partition and copy any
files from the DOS partition anywhere else.