RE: [MiNT] Mount and MiNT

[Mario Becroft <mb@tos.pl.net>]

On Fri, 6 Aug 1999, Julian Reschke wrote:

> I remember an early Mac emulator on the Atari which would start flashing the
> drive and beeping if you removed an unsynced medium. This behaviour could be
> implemented trough an XHDI driver for floppies, if you really want that...

I didn't suggest anything like this, but only that the floppy disc cannot
be locked so therefore the argument about locking the device appears to me
to be irrelevant in this case.

> a) a problem of the program accessing U:, and

What do you mean? Lots of programs access drive U, for example ls when I
type "ls /", bash when I use filename completion on a file in drive U, the
desktop when I open a window showing drive U, the fileselector when I do
the same ... I try to avoid this by never accessing anything via drive U,
but instead via the drive it is actually on, but in that case why have
this drive U at all? However it seems that UNIX-like programs under MiNT
always access everything via drive U, so it's not possible to put
everything on another drive and not use drive U). Even if it is, you would
need symbolic links to the proc, shm etc directories, and then when you go
into one of these directories and out of it again, you are quite likely to
end up in the place where the original file is, namely drive U, and so in
the end it is not possible to avoid using drive U at all.

But maybe there is some other way of not using drive U which I don't know
about. Like I said, I am not so very well informed about this.

> b) wouldn't be such a problem if MiNT would have background DMA.

Except that MiNT doesn't have background DMA, so this doesn't help much...

> Nobody prevents you from removing the drive bit when you eject the disk.
> Just write a program which does just that and call it umount.ttp.

Well, I didn't realise that it was appropriate to do this while the
computer is running but I suppose this would largely fix the problem.
It's funny that nobody ever mentioned this before.

I think there is still a slight problem in that the program would always
have to sync the disc before removing the drive bit, and it is just
possible that something would write to the disc between when it was synced
and when the drive bit was to be removed, but I suppose this is uncommon. 

I still see problems with this arrangement, but maybe there are yet more
kludges which I have not thought of for avoiding these problems.

For example if a disc has an error and I want to repair it, how do I go
about "unmounting" the filesystem in question so that the error can be
repaired by an automated program or by hand, without interruptions by
other programs accessing the drive? How can I make a drive become read
only so that no data can be written to it and it can be modified by a disc
editor, or the computer switched off, without fear of damaging the
filesystem?

-- 
+-----------------------------------------------------------------------+
| Mario Becroft                * Tariland, New Zealand Atari User Group |
| mb@tos.pl.net                * Atari Hardware Developments            |
| http://www.ak.planet.gen.nz/~mario/ * Atari Serial Mouse Interface    |
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