As of the last writing, I hadn't actually started the rsync because I just knew it would work. "rsync --append" apparently doesn't seek to the point where the last one left off. I just took a peek at it and, despite being busy pushing data over the wire, there was no actual progress. The file size was not changing. Thus, I think it was reading its way to the point where it left off. Not useful.
So, next, I tried the "dd" thingy. The "dd" that started at the beginning worked fine. The others copied no data and exited immediately. So I tried my "pcopy" program. Success. After just a few minutes:
$ ls -l total 106724 -rw------- 1 bkorb dev 42827776 Apr 27 12:26 iso-0 -rw------- 1 bkorb dev 9551872 Apr 27 12:26 iso-1 -rw------- 1 bkorb dev 9551872 Apr 27 12:26 iso-2 -rw------- 1 bkorb dev 9551872 Apr 27 12:26 iso-3 -rw------- 1 bkorb dev 9420800 Apr 27 12:25 iso-4 -rw------- 1 bkorb dev 9420800 Apr 27 12:25 iso-5 -rw------- 1 bkorb dev 9420800 Apr 27 12:25 iso-6 -rw------- 1 bkorb dev 9420800 Apr 27 12:25 iso-7 -rw------- 1 bkorb dev 90112 Apr 27 12:20 iso-8
The data rate is huge (8x speedup) compared to single thread. (I set the destination to separate files instead of offsets within the same file.)
