Dear Adam and all, I very much appreciate many of your textual improvements. However, it is very time consuming for us as reviewers to keep track of such substantial changes. It would have been much easier, if you had contributed your changes in an earlier stage. Anyway, I waded through the changes to revision 3 and will comment only on the things that I don't like (consider everything else as excellent): I second Torsten's opinion on p. 49, l. 35-37: This reformulation introduces three times the term "complete". Besides this drawback, I also don't see any benefit from this reformulation compared to the previous version. p. 50, l. 1-2: Similar problem (i.e. 2x"complete"). May I propose: "The start call returns a request handle, which is eventually passed to a completion call." p. 50, l. 8: The part "unless otherwise specified in, or implied by, the description of the operation" has been added. Seem ok to me at first glance. However, we might re-check if this is really necessary and drop it otherwise. p. 50, l. 16: This looks quite redundant to me. I'd propose sth. like the following restatement: "Upon completion of a nonblocking collective operation, the MPI_ERROR field...". p. 50, l. 17: The added postfix "to indicate any errors" seems wrong to me because MPI_SUCCESS is also a valid entry for the MPI_ERROR field. I'd propose to simply omit this postfix. However, I'm not 100% sure because the section about the MPI Status object looks quite confusing in this respect. Btw. there exists also an empty status (which sets all 3 fields) - so we might need to reconsider our decision about setting only the error field for nonblocking collective operations. p. 50, l. 29: "nonblocking collective communications" => "nonblocking collective operations" p. 50, l. 44: You changed "running time" to "minimal time to completion" - this is _not_ the same thing! I'd strongly prefer to stay with the previous terminology. p. 62, l. 36/37: now we have two consecutive "the"s Many thanks! 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)