Anthony Barbachan wrote:
>
> >
> > MSDOS could do this only at a huge loss in performance -- it simply
> > never cached anything on a floppy device. However, seriously though,
> > it wouldn't be that hard to write a daemon (Solaris calls it vold)
> > which monitors a removable-media drive and mounts it on demand.
> >
>
> Actually you could tell SMARTDRV to cache the floppy as well. The
> safety feature was that you had to wait for the command prompt to return as
> a signal that all data had been written. The other way you could tell was
> by watching the light on the drive. Once it went out, the write/read
> operation was over.
>
It wasn't the default, however, and SMARTDRV actually being a disk cache
program came in pretty late in the game.
> > The problem is when the floppy is ejected and the filesystem is busy.
> > If the hardware was designed properly -- and there is such hardware
> > avaiable -- there would be a button that would give a signal to the OS
> > to unmount the filesystem and eject the disk via a motor mechanism.
> > Unfortunately, the bulk of PC hardware isn't, which means you pretty
> > much need to handle the case where the user physically removed the
> > media while it was being used, which leads to some nasty problems even
> > if you never cache a single block.
> >
>
> Would it be feasable to display a prompt to the user (on the console) in
> this case?
>
> - Save video screen and mode
> - Display critical warning prompt message "Please reinsert disk,
> enter to retry, esc to singal error"
> - After user responds restore the video mode and screen.
>
> Something like this could also be used for other such critical warning
> and error messages as well. For example on a disk error or network
> connection gets unplugged.
>
That would be incredibly complex, especially since the kernel doesn't
know how to do that if you're running anything that talks straight to
the video card. Not to mention that it might be entirely inappropriate.
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This archive was generated by hypermail 2b29 : Thu Jun 15 2000 - 21:00:20 EST