> I wonder if FreeDOS has anyl relevance

Well, just yesterday I had to run FreeDOS from a USB in order to run a sas2flash utility that didn't run on Linux or directly via UEFI, so I could flash some firmware to a SAS controller. Seems at least some of us still need it :)

Btw, avoid getting a SAS controller if you can, and get a motherboard that directly supports as many SATA drives as you need. Few things have been as frustrating as dealing with this SAS controller thing.