Reading headerless files (COM files) and Getting Directories in Assembler

What is the best ways to do the following using both firmware and no firmware - ideally with any caveats such as doesn’t work on X-MASS or M4 or Albiero or…

  • Reading headerless files (COM files)
  • Getting Directories in Assembler

does anybody have any references to these online?

UniDOS solved both problems for non-floppies. I can live with UniDOS.