Re: "probably to avoid litigation with IBM"
> Um, if I remember correctly, there was no chance of litigation since IBM did not bother to protect anything via copyright. It was a truly open market.
Your rememberence is incorrect. While the ROM BIOS source was available it was fully protected by copyright (as is all FOSS software). It wasn't until Phoenix did a clean-room reimplementation that there was a cheap enough way to implement clones. IBM did protect its copyrights agressively.