Re: Mounting floppy. Newbie #61

[Pietro Cagnoni <pcagnoni@mclink.net>]

> > I note that when you copy a file to /floppy it seems to be incredibly
> > quick.  Is it in fact written to the floppy at the same time as it
> > appears on /floppy ?
> >
> Ian,
> 
>         All I can say is "Ouch!". Unlike the DOS world, Unix in general,
> and Linux in particular, do not guarantee that data will be written to
> disk immediately after the in-memory copy of the disk blocks have been
> updated. Unixes, in general, cache such info, and typically write out to
> media (floppy disks, hard drives, etc) only when its efficient to do so.
> Thus, when you make drastic changes to the contents of a floppy disk, the
> in-memory copy of those disk blocks gets updated, and this happens quite
> fast. However, unless this copy is written out to the floppy itself, the
> changes will not be permanent.
> 
>         There is a standard way that Unixes support to force the write to
> media. This is called the 'sync' command. If you had done 'sync' after
> changing the contents of your floppy, you would have seen that your system
> was writing to the floppy - which does take a significant amount of time.
> Given the symptoms you describe, I would guess that you didnt do a 'sync'
> before you popped the floppy disk, and thus your backups were never
> written to floppy before you popped out the drive.

the Right Thing to do is umount the floppy before pushing the eject
button.

pietro.