Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!usc!zaphod.mps.ohio-state.edu!wuarchive!uunet!nss1!rca
From: rca@nss1.com (Rich C. Ankney)
Newsgroups: comp.unix.internals
Subject: Re: shared libraries can be done right
Message-ID: <1991May28.135859.644@nss1.com>
Date: 28 May 91 13:58:59 GMT
References: <20May91.042630.9136@franklin.com> <675052046.101301@paladin.owego.ny.us>
Distribution: usa
Organization: Simpact Associates, Inc., Reston, VA.
Lines: 12

I think it is important to point out that A-series library calls result in the
called function running on the caller's stack; i.e. no context switch is ever
required.  The somewhat slower execution time is measured in microseconds and
is due to the need to update the (static) stack frame linkages to reference  
the library's environment (i.e. global variables).  (The A-series architecture
is completely stack-oriented and this kind of inter-stack reference has been
supported by other means since the early 1970s.  As I recall, libraries debuted
in the mid-1980s, and much of the A-series system software was modified to
become libraries instead of using ad hoc mechanisms to do the same thing.)

Still one of my favorite architectures in the "elegance" category, even if
they don't know how to market it...