Originally Posted by
pit234a
For a non Unix-User, simple: impossible.
Thats my opinion, but I am low level Unix-User.
Let me try to tell why I think so.
Mount says, giving a file system a place, where it is visible within your system tree of folders. This is called a mount point and may be any folder in your system. A file system has to be known by the kernel directly or through a so called kernel module, that can be loaded or unloaded at runtime if needed. It will be loaded automatically and operate with the desired options, in invoking the mount command. The ordinary mount looks like that: mount -t(file system type) -o(options) /dev/(entry that represents the desired file system) /path/to/mount_point. Of course, every single detail must be present and known to the system. You won't be able to mount on a non existing mountpoint and you won't be able to mount any unknown file system either. That is the problem. CD or DVD have a well known and classified file system and their iso-imgs represent just the content of a CD, so mounting means not much more, than creating an entry that represents this file system in /dev and mount it as usual. I show this detailed for FreeBSD:
mdconfig -a -t vnode -f '/path/to/my.iso' -u 0
creates an entry /dev/md0 that represents my.iso, what should be a CD img.
mount -r -t cd9660 /dev/md0 /path/to/mount_point
would mount this, just as it would be a CD, -t cd9660 stands for the cd- file system.
With GNU, there is a nice mount option, -o loop, that can mount those iso-imgs directly without first creating and configuring a device md0.
Free-BSD and GNU are full featured Unix Systems, GNU normally runs on Linux.
Thecus has busybox/Linux, what is a limited Unix. In my version, I don't see -o loop and no mdconfig, so I can't say, how they do it with your version now, but I am sure, it will follow the same principal and it will need to know the file system that is wanted. Lets say, you want NTFS, the famous and good M$ file system. You never could mount anything formated in NTFS, without using the right kernel module. It is not enough, to tell the system to use NTFS, the module must be present and known to the system. In full featured Unix Systems, you have a chance to build this modules later, at some point, but with busybox, you will have to integrate this during system build time. If Thecus did so with CD file system, they could do that, because this is well known and common. The same might be true for NTFS or FAT and FAT32(VFAT). But it cannot be true for any desired file system in the world and you still would have to know, what is in the corresponding img-file. You cannot see this by looking at the extension or so.
If you know, what is used inside this img and if the file system would be supported, you would be able to mount this img. If it is mounted, you could export it. The mount point must than get an entry in your /etc/exports, what lists your NFS shares. But this has to be read by the NFS-server when it starts. You would have to restart that after creating an entry and after mounting the img, than you should get it exported correctly. Its not the img, its the mount point that you have to export. Or this mount point has to be in an already exported folder and this one is exported with the option -alldirs, so that you are able to browse in that iso- mount point. After mounting the iso, you would be able to reach it.