From: Bruce Evans <[EMAIL PROTECTED]>
Date: Sat, 10 Feb 2001 06:24:20 +1100 (EST)
> On Fri, 9 Feb 2001 [EMAIL PROTECTED] wrote:
> > From: "Kenneth D. Merry" <[EMAIL PROTECTED]>
> > > Hmm, can you demonstrate the problem?  The write-protect check in the od
> > > driver is one of the things that the da driver doesn't have.  I figured it
> > > wouldn't really be necessary, since any attempted writes would be returned
> > > with errors.
> > 
> > The problem is you cannot unmount after -rw mount with a write-protected 
> > medium. 
> This is essentially the same bug that causes problems for writing to
> write protected media or unwriteable blocks using the block device.

Are there any reason device drivers do not check if thier devices are
writable or not when they are opened ? I think returning an error
value, like `od', is the easiest way to avoid this problem.

> I first saw this problem for a floppy driver that I wrote in 1984.  It
> retried endlessly.  Users did not like this :-).

I was told not to write-protect floppies when using UNIX :-(

// Noriaki Mitsunaga //

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