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From: ken@rochester.ARPA (SKY)
Newsgroups: comp.mail.uucp
Subject: Re: cancelling mail messages
Message-ID: <22899@rochester.ARPA>
Date: Thu, 4-Dec-86 17:33:29 EST
Article-I.D.: rocheste.22899
Posted: Thu Dec  4 17:33:29 1986
Date-Received: Fri, 5-Dec-86 03:54:20 EST
References: <40@dcl-csvax.comp.lancs.ac.uk> <119@devon.UUCP> <1337@munnari.oz> <8814UH2@PSUVM>
Reply-To: ken@rochester.UUCP (SKY)
Organization: U of Rochester, CS Dept, Rochester, NY
Lines: 24

Moral issues aside, there are two stages at which a cancel request
could arrive, when the message is still in the local queue, and when
the message is already sent out.

Sending out a cancel request in the latter case is fraught with
security risks.

Cancelling mail while it is not yet sent is analogous to retrieving it
from your physical out box, *provided* you control the machine or the
management allows you to do this. Analogy: your company allows you to
retrieve mail before it goes out. This is a reasonable thing to want.

But with the low latency of mail systems these days, this feature is
probably of marginal value.

So yes, think a little more before firing off in a hurry.

As for saving other peoples time by cancelling mail which is no longer
relevant, well they will take only a moment to decide if it is.  Just
about the same amount of time it takes you to compose a cancel
request.  Since other people will occasionally inconvenience you with
no longer relevant mail too, I see that as a fair tradeoff.

	Ken