Convergence of AIX and 4.3BSD

[Charlie Sauer]

Following is an abstract of a paper we plan to write:

CONVERGENCE OF AIX AND 4.3BSD

   Charles H. Sauer (1)
   Kathy A. Bohrer (1)
   Tom Lang (1)
   Conrad Minshall (2)
   Gary L. Owens (1)
   Kris Solem (3)
   Bruce J. Walker (4)

                            (1) IBM Advanced Engineering Systems, Austin, TX
                            (2) IBM Technical Computing Systems, Palo Alto, CA
                            (3) formerly IBM Technical Computing Systems, 
                                now MIPS Computer Systems
                            (4) LOCUS Computing Corporation, Santa Monica, CA        

AIX started with a number of BSD features, e.g., 4.2 signals and concurrent
groups[1]. Over time, additional features associated with BSD, such as pty's,
select, sockets and sendmail have been added, with new features being added in
each release.  Based on this experience, and experience with 4.3/RT, it 
appeared that fairly strict BSD compatibility could be achieved, and the 
authors and others set out to define such compatibility.

This paper describes methodology and decisions made in defining a convergence
of BSD 4.3 and AIX.  This convergence will be reflected in the AIX Family
products and the version of AIX to be provided to the Open Software Foundation.

Among the goals of the work were

   POSIX compliance

   Base SVID functionality at the SVR2 level

   Compatibility with documented and undocumented BSD 4.3 characteristics
   and interfaces

   Compatibility with existing AIX interfaces

   Completeness - providing essentially all BSD 4.3 functions

   Minimal redundancy - except in a few cases where redundancy seemed
   inescapable, conflicts were resolved to provide a single merged
   definition of system call, library and command interfaces.  Users
   and programmers should normally not be conscious of the historical 
   basis of the converged interface.

   Portability - minimizing porting effort for users and applications
   associated with existing AIX and 4.3 implementations.

In addition, many of the system administration facilities were addressed in
a converged manner.  The effectiveness of the approach is demonstrated by
success with test suites originally designed for AIX/RT and 4.3/RT prior
to the convergence effort.

ACKNOWLEGEMENT

Many others contributed to this work, including, from IBM Advanced Engineering
Systems: Rob Cordell, Jim DeGroot, Patrick Goal, Carolyn Greene, Larry Loucks,
Jim Mott, Mike Schmidt, Doug Steves and Ken Witte, from IBM Data Systems 
Division, Johnny Barnes and Heinz Graalfs, from IBM Research, Marc Auslander,
from IBM Technical Computing Systems, Larry Breed, Bruce Campbell, Sanjay 
Challani, Tu-An Cheng, Tri Ha, Chirag Jain, Jason Kosol, Betty Lee, Derrick Mar,
Teri McConnell, Lisa Repka (now with Evans and Sutherland), Laura Richardson 
and Dave Zittin (now with Sun Microsystems), from Lachman Associates 
Incorporated, Jim Norris, from LOCUS Computing Corporation, Bob Peterson, 
and from Sunday and Associates, Roy Gordon.

REFERENCE:

1. L.K. Loucks and C.H. Sauer, "Advanced Interactive Executive (AIX) Operating
   System Overview," IBM Systems Journal 26, 4 (1987).
-- 
Charlie Sauer   IBM AES/ESD, D18/802     uucp: ut-sally!ut-emx!ibmaus!sauer
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