The original complaint
Actually, if you read TSG's original complaint (courtesy of the WayBack Machine):-
https://web.archive.org/web/20170704181155/http://www.groklaw.net/article.php?story=20040704170212250
you'll find their characterization of Project Monterey, a joint initiative between IBM and The SCO Group to develop a 64-bit version of a UNIX-based operating system for "Intel-based processing platforms." Here's the actual text of the complaint:-
" Project Monterey
50. As SCO was poised and ready to expand its market and market share for UnixWare targeted to high-performance enterprise customers, IBM approached SCO to jointly develop a new 64-bit UNIX-based operating system for Intel-based processing platforms. This joint development effort was widely known as Project Monterey.
51. Prior to this time, IBM had not developed any expertise to run UNIX on an Intel chip and instead was confined to its Power PC chip.
52. In furtherance of Project Monterey, SCO expended substantial amounts of money and dedicated a significant portion of SCO’s development team to completion of the project.
53.Specifically, plaintiff and plaintiff’s predecessor provided IBM engineers with valuable information and trade secrets with respect to architecture, schematics, and design of UnixWare and the UNIX Software Code for Intel-based processors.
54. By about May 2001, all technical aspects of Project Monterey had been substantially completed. The only remaining tasks of Project Monterey involved marketing and branding tasks to be performed substantially by IBM.
55. On or about May 2001, IBM notified plaintiff that it refused to proceed with Project Monterey, and that IBM considered Project Monterey to be “dead.” In fact, in violation of its obligations to SCO, IBM chose to use and appropriate for its own business the proprietary information obtained from SCO."
The context here is critical in a technology sense, perhaps less so in a legal sense.
There are a couple of critical issues with the text of that initial complaint. The first is that "The SCO Group" - the party bringing the complaint - continue to refer to "OldSCO" and "The SCO Group" interchangeably, using "SCO" as the label, in a largely successful attempt to bamboozle the Court in to thinking that TSG had a bigger role in this story than was actually the case.
The second is an attempt to convince a (non-technical) Court Judge that somehow there is arcane magic involved in getting a 64-bit version of a "UNIX-based operating system" to run on an Intel-based platform. Here's why that is utter tosh:-
1. IBM invented the "PC platform" and arguably had more and better knowledge of getting code to run on it with the exception of maybe Microsoft and Intel. Certainly they had a much better understanding of the platform than any version of SCO - ***it was their frikkin' platform***...
2. Absent all the other factors required, the steps needed to get a 64-bit version of a UNIX-like operating system running on a 64-bit PC platform would be something approximately like this:-
2.1. Start with 64-bit hardware running a 32-bit operating system. Ideally that would be 32-bit UNIX, but it didn't have to be. [ This was readily available - i.e. Xenix, etc.].
2.2. Write a C compiler that produces 64-bit code, taking advantage of new instructions and new address space. [ This has been done many, many times as basic C compilers [such as gcc] get ported to new hardware platforms...]
2.3. One-at-a-time, write the 64-bit code files needed to get a bootable kernel for the target platform.
2.4. Copy the kernel files to a target/destination boot disk, including a utility to lay down a 64-bit boot sector.
2.5. Once you have enough of the basic files needed to create a bootable kernel and shell, boot your hardware with the new image...
2.6. The first thing you do once you have a running image is write a 64-bit C compiler for the new platform, along with it's tools...
2.7. Port the 64-bit compiler to the new prototype OS...
2.8. Start taking your 32-bit source code, one application at a time, and recompiling it using the new 64-bit compiler to build out a fully-featured OS...
2.9. Package up your 64-bit files with a 64-bit installer...
2.10. Perform an all 64-bit test install to make sure everything works.
At this point, you have "enough" of a 64-bit platform that you can start porting code in earnest. As the complaint from TSG notes, you can start with library files and build out from there.
But for SCO to try and claim that they had unique knowledge and expertise and it would have been impossible for IBM to create a 64-bit version of UNIX able to run on the Intel platform is just such utter, utter tosh it's difficult to know what they could possibly have been thinking.
Interestingly, you will see if you search Groklaw that IBM only really objected to TSG's egregious motion practice, they did not waste their time trying to promote their possible defenses ahead of the trial. So we don't actually know how much fun IBM would have had in cutting this nonsense to pieces...
I offer all of this as interesting context, because though you might not have realised it, the very heart of TSG's complaint against IBM was that only they, not IBM, had the skills and experience needed to "port" a UNIX variant from 32-bit to 64-bit.
Curiously, for all you nerds out there... the first 64-bit [stable] Linux kernel was the 1.2.x, series [for the DEC Alpha [on which PowerPC was based], which released in 1995 - 8 full years before the TSG lawsuit against IBM dropped. Which, if any evidence were needed of the falsity of TSG's complaint, might be a pretty big clue.