<html><head><style type="text/css"><!-- DIV {margin:0px;} --></style></head><body><div style="font-family:times new roman, new york, times, serif;font-size:12pt"><DIV style="FONT-SIZE: 12pt; FONT-FAMILY: times new roman, new york, times, serif">Peter,</DIV>
<DIV style="FONT-SIZE: 12pt; FONT-FAMILY: times new roman, new york, times, serif"> </DIV>
<DIV style="FONT-SIZE: 12pt; FONT-FAMILY: times new roman, new york, times, serif">Of all the links you have been given, put this one at the top of your list. Commit to spending an half hour reading, much less than this thread! :)</DIV>
<DIV style="FONT-SIZE: 12pt; FONT-FAMILY: times new roman, new york, times, serif"> </DIV>
<DIV style="FONT-SIZE: 12pt; FONT-FAMILY: times new roman, new york, times, serif">> (concerning distributed programming, and event-loop concurrency)<BR>> <A href="http://www.erights.org/elib/index.html" target=_blank rel=nofollow><FONT color=#0000ff>http://www.erights.org/elib/index.html</FONT></A><BR><BR></DIV>
<DIV style="FONT-SIZE: 12pt; FONT-FAMILY: times new roman, new york, times, serif">I also wasn't as clear as I could have been.</DIV>
<DIV style="FONT-SIZE: 12pt; FONT-FAMILY: times new roman, new york, times, serif"><BR>> When a message is sitting in an inbound queue on a process waiting </DIV>
<DIV style="FONT-SIZE: 12pt; FONT-FAMILY: times new roman, new york, times, serif">> for that process to do get to it it is in essence blocked until it gets </DIV>
<DIV style="FONT-SIZE: 12pt; FONT-FAMILY: times new roman, new york, times, serif">> processed. If the process is only processing one inbound message at </DIV>
<DIV style="FONT-SIZE: 12pt; FONT-FAMILY: times new roman, new york, times, serif">> once it is possible for a dead lock to occur when multiple processes </DIV>
<DIV style="FONT-SIZE: 12pt; FONT-FAMILY: times new roman, new york, times, serif">> are in a similar situation with each other. Both processes waiting for </DIV>
<DIV style="FONT-SIZE: 12pt; FONT-FAMILY: times new roman, new york, times, serif">> the message that would let them continue which is sitting blocked on </DIV>
<DIV style="FONT-SIZE: 12pt; FONT-FAMILY: times new roman, new york, times, serif">> the other's queue. That's all. Classic deadlock case. <BR></DIV>
<DIV style="FONT-SIZE: 12pt; FONT-FAMILY: times new roman, new york, times, serif">Ok, with your terminology, and some of mine, a message in a queue feeding a Vat is blocked until the Vat gets to it. Ditto with Vat 2. The mistake in your classic deadlock case is to assume that the message could also get blocked because it is waiting on the msg in Vat 2. This does not happen. If there was an unresolved reference waiting on resolution from a remote computation, it is represented as a promise. So message 1 would have a promise for the outcome of message 2. It would NOT be on the queue for Vat 1. It would be sitting as the argument in a #whenMoreResolved msg to the promise. And when that promise resolves, it would then run. </DIV>
<DIV style="FONT-SIZE: 12pt; FONT-FAMILY: times new roman, new york, times, serif"> </DIV>
<DIV style="FONT-SIZE: 12pt; FONT-FAMILY: times new roman, new york, times, serif">Now, you are further saying that promise will not resolve because both are mutually dependent on each others results. So you are saying that in a sense they are deadlocked. Again this cannot happen. There is no way for you to kick off computation 1, with the promise to computation 2, unless the computation 2 had already been kicked off. DItto for the other direction. So it is impossible to construct this promise deadlock.<BR></DIV>
<DIV style="FONT-SIZE: 12pt; FONT-FAMILY: times new roman, new york, times, serif">Cheers,</DIV>
<DIV style="FONT-SIZE: 12pt; FONT-FAMILY: times new roman, new york, times, serif">Rob</DIV></div></body></html>