Dear all, here are a couple of comments from my site (referring to the new version that Torsten sent out an hour ago): p 4, l 26: old typo? "indentifier" -> "identifier" p 49, l 36: question for "the communication may progress independently of the computations at all participating processes": What about all the Reduce operations which involve both communication and computation? Should we replace "the communication may progress" with the more general "the operation may progress"? p 50, l 14: same argument as above; replace "collective communication" with "collective operation" p 50, l 31: "using normal point-to-point" is not accurate/sufficient enough => "using nonblocking point-to-point" p 65, 5.13: The example is good but the current text is bad. It is simply not allowed to call NBC in a different order. If a certain implementation runs into a deadlock does not matter. This would even be on of the better scenarios (i.e. an easy-to-noticeable error). Other implementations could complete both bcasts (because it thinks they match) but provide the wrong data (i.e. the data from the other bcast or even a mixture?) - which is a much harder failure to detect. p 66, example 5.25: should we add sth like the following at the end? "Note: Using nonblocking collectives can fix such problems, see example 5.34." p 69, l 32: maybe better "However, communicator construction might induce overheads and consume resources so that this should be used economically." p 70, example 5.31: To me this example is not "per se" illegal. Both operations simply don't match - that's fine. However, it is possible to extent the example so that the final program is still a valid MPI program. Maybe just add sth. like "in this form" or "without additional collectives that match". Best regards, Christian -- Christian Siebert, Dipl.-Inf. Research Associate NEC Laboratories Europe, NEC Europe Ltd. Rathausallee 10, D-53757 Sankt Augustin, Germany Phone: +49 (0) 2241 - 92 52 44 Fax: +49 (0) 2241 - 92 52 99 (Registered Office: 1 Victoria Road, London W3 6BL, 2832014)