Both Ms-DOS and Os/2 are single user operating system. Their respective file-systems lack most of the features expect from a multiuser operating system like Linux.
For one, there is no file ownership. It would mean that when a Dos hard drive is mount into the Linux file-system tree, files would be available to any user on the machine.
Keep in mind that Linux is a multiuser system. It is fairly easy to create user accounts for co-workers on your machine so they can share your CPU or system resources. It would not be nice to find out later that everyone have access to every personal file you have in your Dos partitions.
Linux offer a neat solution to this. You can logically apply an ownership and permission flag to all files and directories in a Dos partitions. No special data is written to the partitions. It is simply a presentation mode used by Linux.
Here are the options you can control
Text file are stored in a slightly different format on Ms-DOS and Os/2, compared to Unix and Linux. The difference lie in the way end-of-file are identified.
Ms-DOS use a sequence of two characters, an
ASCII Carriage-return
followed by an ASCII Line Feed
.
Unix use only a single Line Feed
.
The msdos
, umsdos
and hpfs
file-systems share
one option to make life easier when sharing file on a hard
drive between Linux and Ms-DOS or OS/2
Here are the mode available:
Once a translation mode is selected, it is done both at read and write time, making this almost transparent to Linux application.
Please note that the current trend is toward flexible utilities (editors) which can handle both format instead of using a file-system trick like this one.