Re: "SCO code" in Linux?
AIX was originally built from 4.2BSD with a mashup of AT&T System V stuff, and has no USL/Novell Unix in it whatsoever as far as I know.
It's more complicated than that, since there are four different AIXes:
- AIX 1 and 2 for the RT, created by IBM and ISC, was based on SVR2 with some additions from 4.2BSD, running on top of the RT's VRM microkernel. ISC had earlier ported System III to the PC (PC/IX).
- AIX 1 for the PS/2, created by Locus under contract to IBM. If memory serves, AIX for PS/2 was also primarily an SVR2 derivative.
- AIX/370 for the mainframe. Also developed by Locus, and similar to AIX for the PS/2.
- AIX 3 et seq. for RIOS / POWER / PPC machines. IBM kernel (pageable, modular, unified virtual storage mangagement; not much like the SysV or BSD kernels). Userland a mix of SVR4 and BSD with numerous IBM idiosyncrasies, such as the XCOFF object format and IBM's shared-object mechanism, the ODM, and SMIT.
USL didn't split off from Bell Labs until 1989, according to Wikipedia, by which time AIX 3 was already under development. So, yeah, no USL influence per se - they have a common ancestor in SysV, but that's it. And Novell didn't acquire USL until '93.
(Now, of course, we at Micro Focus own Novell. So as far as I can tell, we own the copyrights to the former-USL source code. Novell gave the UNIX trademark to The Open Group.)
That said, there was Project Monterey between IBM and SCO (and Sequent and Intel and maybe some others), which could have introduced some later USL-owned code into AIX 5L. That wasn't until circa 2000, though - long after the original AIXes were developed.