[MUD-Dev] Re: lockless system - foolproof?

[J C Lawrence]

On Mon, 31 Aug 1998 07:40:10 -0600 
T Alexander Popiel<popiel at snugharbor.com> wrote:

> In message: <E0zDMqj-0000QX-00 at mail.kanga.nu> J C Lawrence
> <claw at kanga.nu> writes:

>> Assume a SHOUT command that passes its argument to all players and
>> NPCs.  The obvious (and actually fairly common) approach is
>> something as follows:
...

> This sounds like it would open your game to event-order confusion.

Yes, I do not guarantee or even attempt to enforce any given order of
execution.  

> Imagine someone holding an auction via shout... and two people shout
> at nearly the same time.  Because of the separation of different
> targets into different events, the auction master and each of the
> shouters could be notified in different events.  Because of your
> parallel execution race-condition for C&C, they could hear the
> shouts in different orders.  This'll lead to some very nice flame
> festivals when the item under auction gets sold to the "wrong"
> person...

This assumes that the propagation of shouts across the land is assumed 
to be instantaneous.  Is that really an automatic assumption?  

That said there are cases where the order of execution is important
(this has previously been discussed under the panama canal scenario
among others) for which cases I provide frameworks which can be used
to enforce an execution sequence across a defined set of events.
Typically this is accomplished via an external referee object which
mediates the sequence.

In the general case however, order is both unenforced and
unpredictable.  I don't see this as a problem.

--
J C Lawrence                               Internet: claw at null.net
(Contractor)                               Internet: coder at ibm.net
---------(*)                     Internet: claw at under.engr.sgi.com
...Honourary Member of Clan McFud -- Teamer's Avenging Monolith...