I talked with John Mashey this PM and asked him about the huge file stuff and PWB1.

First, he did not remember that they had done that, but ...  

He then emphasized that the PWB team was running the first (and for a long time the largest) "computer center" using UNIX in the Bell System in Piscataway - supporting over 1000 programmers as a front end to the mainframes. His memory is that they mostly used 88 Mbyte RP04s [remember, at the time, RK05s were only 2.5M].  Needing to support a megabyte or larger file would have been relatively rare for them.  He also pointed out they needed to run their system on systems as small as 48K byte 11/40s to as large as 1M 11/70s.

As he said, his team tried to track Dennis and Ken's Research system closely since the PWB team was not primarily in the system development/enhancement business - i.e. they tied to keep what would become PWB1 and whatever was running at Research as similar as they could [he told some stories about running to MH to get Dennis' latest compiler binary because the incremental development scheme dmr used would make someone like PWB that took snapshots at different times, end up with a compiler that could not compile itself --#1#]. But the PWB group >> was << interested in making the system they were running as reliable as possible and, more importantly, being as graceful as possible when different resources were exhausted.

He said it would have made sense for them to remove the "huge file" support to help to defend against running out of space and the system having issues [V6 was extremely ungrateful about that condition]. So limiting file size became a simple quota, if you will. A runaway program was less likely to take the system out. So the process would die because the file got too large (or, to use the IBM shop term in those days -- ABEND).

#1# He also regaled a bit about Ken's infamous Turning Award hack and discovering symbols in the compiler binary they could not understand ;-)