The Bach book is definitely good, but it is written to describe System V
(Bach was an AT&T employee, after all).  For those details that haven't
changed since 6th Edition in either chief variant (a frightening amount :-),
the Bach book is an excellent reference.  For anything that BSD changed,
though, it is scanty at best (BSD material is brought up mostly for
"compare and contrast" cases).

I wonder if Leffler, McKusick, Karels, and Quarterman can be forced to
write "The Design and Implementation of the 4.4BSD [Mmmph] Operating
System"?  (I wonder what J. Lyons is doing these days...)

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