Loop devices, mounted disk image,all vanish from NAS

Here I am, going great guns extracting old DisplayWrite 3 files from my stash of 5-1/4 inch floppy disks, when an unexpected consequence develops: I had made a series of about twenty disk images with the FC5025 hardware and software described previously, but I was converting them right on my NAS (network attached storage hard drive, running a linux operating system, I recall) when I discovered that the converted files, now plain text, had all disappeared. For some, even the folders in which they resided had disappeared.

My mistake, it would appear, was in assuming that my act of copying the mounted folders from my Trisquel 7 installation to my NAS created permanent files on the NAS; maybe I had copied their "mountedness" as well because the two file structures are locally the same.

Not so fast. For the one batch of ten, I had also copied the image files to a higher directory on the NAS. Those folders just lost the converted files, which I had converted on a *XP computer and saved back to the NAS. A later batch of ten folders had had the image files mounted into them with the Trisquel computer, but I had not copied the image files to their own places on the NAS like I had with the first batch. That later batch of ten folders had lost, not just their supposedly mounted contents (written with the mount command, using the -o loop syntax) but also all their converted files, as well as the folders. Poof ... gone.

Fortunately what I lost was just a couple of hours of work.

I have now "corrected" the situation by copying all the image files onto the *XP's hard drive along with the folders containing the mounted versions of those image files, where the idiosyncrasies of linux cannot interfere. I had been trying to simplify my operations by putting the conversions onto the NAS where I could copy them two ways from there - onto the Trisquel computer and also, in a second operation, onto the *XP computer, each one of which is a mirror of the other.

I suspect that what I had been doing wrong was not realizing that while Trisquel was placing mounted image files onto the NAS, the NAS was temporarily mounted and a part of the Trisquel operating system, and that while I was thinking that I was "saving" files from the converter software on the *XP into what I thought was that same NAS, I was not really saving anything into the Trisquel computer, even though it looked that way from the perspective of the converter software on the *XP computer. The Trisquel installation simply ignored what the *XP computer was telling me it was doing to it through the NAS.

Nice - that's one of the strengths of linux, it would seem. I cannot sneak into Trisquel by way of that NAS without asking nicely through an ftp program.

Have I got this right, or have I discovered a "feature" of the following command ?

> sudo mount -t msdos ~/Desktop/Floppies/disk000x.img ~/Desktop/Floppies/DW3/Disk-000x -o loop <