On Mon, 19 Jun 2000, Chris Swiedler wrote:
> Richard Stallman <rms@gnu.org> wrote in message
> news:<fa.h09h36v.1a1sro5@ifi.uio.no>...
>
> > Is there any possibility of making Linux handle file systems on
> > floppies like MSDOS, so that there is no need to explicitly mount and
> > unmount a floppy drive in order to access floppies through the file
> > system?
>
> In discussing this problem, several people had possible solutions which were
> all shot down with a similar counterargument: the kernel can't assume that
> the user who is using the floppy drive is at the console. Apparently,
Actually there are two issues here. One is: how to correctly route the
information that the diskette has been removed. This problem exists for
every removable medium, so we can either ignore it as has been done in
general, or develop a general solution (which might be nice to have). I
suspect that any such solution is going to be incompatible with the
present request, since there's no way for the OS to know where the user
has gone after sticking the floppy in the drive, unless the user tells it.
> Windows can automount floppies in part because it makes the assumption that
> there is only one user on the machine--an assumption which Unices by design
> can't make.
Nope. DOS, Win/DOS, and NT don't "automount" anything. They don't have
the concept of mounting media. The other challenge presented by this
request is that of maintaining cache coherency. MS' products avoid this
problem by not caching writes to the floppy. Caching is the chief
technical reason for operating systems to have the mount/unmount concept.
Actually there is a gadget called SMARTDRV which adds an I/O block cache
to DOS or Win/DOS. In effect it must automount any volume that it is
directed to cache. It has no way to auto-UNmount, though; if you allow it
to cache writes then IIRC you must give an explicit command before
removing a removable volume or data loss can occur. So these products
have the same difficulty that is being discussed here.
So, how hard is it to make MS_SYNC default for FAT-based filesystems, and
is this sufficient to prevent data loss due to lazy writing?
-- Mark H. Wood, Lead System Programmer mwood@IUPUI.Edu 2000-05-05 13:27:15 GMT -- still no icebergs in the White River- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.rutgers.edu Please read the FAQ at http://www.tux.org/lkml/
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