Subject: Re: (2nd send) opinion sought about EOM handling for tapes
To: Matthew Jacob <mjacob@feral.com>
From: Todd Whitesel <toddpw@best.com>
List: tech-kern
Date: 07/13/1998 18:15:42
> EARLY WARNING behaviour enabled is defined as a guarantee that
> if early warning (logical EOM) is detected, the tape driver
> will ensure that the writing application will be notified by
> a 'short' write (non-zero residual). This may be delivered
> by either the EOM itself causing a residual, but also may
> require the driver to internally 'note' that EOM has occurred
> and to terminate the next write immediately with the residual
> set to the byte count of that request.
Wait a minute, in the latter case how do you know that it's a residual
and not a complete write?
Maybe I missed something, but it seems that these methods have a slight
problem when your "short write" hasn't written any bytes yet, so the only
'correct' residual would be exactly zero.
Todd Whitesel
toddpw @ best.com