On 9/30/2021 5:39 AM, arnold(a)skeeve.com wrote:
Paul Ruizendaal via TUHS <tuhs(a)minnie.tuhs.org>
wrote:
So far, I have not come across any shared library
implementations or
precursors in early Unix prior to SunOS 4.
In more or less the same time frame, the AT&T UnixPC / 3B1, which was
OEM'ed from Convergent, had shared libraries. This was ~ 1986.
I don't know the details of how it worked and how one built the shared
libraries; I am sure that it was an independent implementation from Sun's.
This was done on top of a System V Release 2 kernel. Later versions
of the OS had some bits of the SVR3 user land, but the kernel remained
SVR2 based.
There is a 3B1 emulator and disk images for it available for anyone
who really wants to go back to a system with short filenames and no
job control. :-)
I'm very hazy on the details, because I wasn't directly involved, but we
had shared libraries in AIX for the RT starting with the initial release
in 1986 (based on SVR1). Larry Loucks did most of the design, with help
from ISC folks and maybe Rick Simpson. Larry mentions this work in our
AIX 2 paper
(
https://technologists.com/sauer/Advanced%20Interactive%20Executive%20(AIX)%…)
but I don't see any useful description, nor do I see anything useful
skimming
http://www.bitsavers.org/pdf/ibm/pc/rt/ docs. A more
sophisticated shared library design was one of the additions in AIX 3.
Charlie
P.S. That paper and
https://technologists.com/sauer/SA23-1057_IBM_RT_Personal_Computer_Technolo…
do include a bit more discussion of our memory mapped files since
support for those was a primary goal of the 801 virtual memory design
(summarized in the "Rosetta" paragraph of
https://notes.technologists.com/notes/2017/03/08/lets-start-at-the-very-beg…)
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