[TUHS] 8th Edition timeline

Here is a question for the old hands from the Labs, I’m trying to get the timeline of some development steps right. The two main things are: when did the 4.1 merge take place, and when were ‘streams’ added? Going by file dates, the surviving 8th edition source appears to be from 1985. I can see that a lot of files in /usr/include did not change after Jan 1982 (e.g. nlist.h). This suggests that early in 1982 the merge between 4.1 code and 32V code took place, to create the foundation for further development (“proto 8th edition”, so to speak). Similarly, there are a dozen or so files in the kernel that all have a file date of November 1982. The most interesting one of these is “dtline.c”, a character mode Datakit driver: it uses ‘streams’. This suggests that there was a further code merge late in 1982 and implies that ‘streams’ were developed prior to that date. From the S/F-Unix papers it seems that ‘streams’ did not exist in 1981, at least they are not mentioned in an otherwise comprehensive set of papers. On the other hand, the S/F-Unix work was done in the Exploratory group, not the Research group: maybe it was inappropriate to mention. All in all, my hypotheses would be that: - the 32V/4.1 merge took place early in 1982 - ‘streams’ were developed in 1982 on 32V (maybe also V7) systems - a further merge took place late in 1982 that combined the new base with latest developments Does that sound correct, or was it all different? Related is the question when the "file system switch" was added. It must have been later than 1981 and before 1985, but I have not been able to pinpoint it further. Paul