On Mon, Jun 1, 2020 at 6:19 AM Paul Riley <paul@rileyriot.com> wrote:
Is there a Windows or Linux utility to create a disk image in any of the above formats, from a local folder tree? 
What I think you are asking, is there a utility for a modern OS that will walk a local folder tree on my OS and create a new file whose structure is that of the file system for OS <insert yours here>.

The issue is not the device as much as the OS and disk file layout.    As far as UNIX (or simh at the OS level) is concerned, the disk is just a linear array of bytes, addressed by blocks.  The physical format is not seen by UNIX.

There are numerious utilities, as well as 'foreign file systems' that are available.   For instance, many Unix's can write RT-11 and MS-DOS format with standard utilities.   It really depends the OS.  That said,
if the target OS is modern enough to support NFS or Samba, the easiest way might be export the file system from local system, and then running a simulated OS, 'mount' the file system.