MERT absolutely predates PWB 1.2. MERT has papers starting in 1975 while pwb 1.2 is 1978 or 1979.
I can not say, I have any knowledge so I would trust Rob's sources, but ... I also what I would have thought MERT predates PWB. Heinz, are you able to illuminate any of these details?
The group that created PWB may well have started before the MERT group, at least from what I can find documented in early papers... However, the first release we have of PWB is labeled 1.0 and it is 1977. The ACM MERT papers are from 1975.
MERT was V4 while releases of PWB were V6 based.
I can verify and agree with the later of PWB 1.x being 6th edition, but the MERT tidbit is interesting/thought-provoking. I frankly would have expected the MERT folks to have started with something closer to 5th and then tracked any significant differences as possible.
I believe that they did track releases. And this may be a case of rolling release. I'm told, but can't find a good reference for it, that editions were just a manual thing and that there wasn't a 'master tape' made of each edition until late in the process (like maybe as late as the 7th edition since I see references to different versions of the 6th edition, though that may be nothing more than the '50 patches' tape). This makes some of the traffic difficult. The Network Unix folks started with 5th editionish release, but had frequent updates during their work as the 6th edition was being prepped and then settled on the 6th edition to release their work (since the tapes we have of it are of a lightly-modified 6th edition (at least relative to dennis_v6). I'm also unsure of when the first "release" of MERT was, which may be critical to answering that question...
Warner