This is the process used to achieve the "IBM PC Compatible" system you're probably using right now (including your Mac). Reading up on the development of the Compatibles is a good way to understand how to do reverse engineering correctly.
You should always emphasize that its the correct way _in the US_. As somebody already mentioned, HN readership is international, and said restrictions on reverse engineering do not apply everywhere. Also the author, judging by his name, doesn't seem to be a US citizen.
"This manual describes the various units of the IBM Personal Computer AT and how they interact. It also has information about the basic input/output system (BIOS) and about programming support.
The information in this publication is for reference, and is intended for hardware and program designers, programmers, engineers, and anyone else who needs to understand the design and operation of the IBM Personal Computer AT."
It includes the source listing of the PC AT BIOS, as well as complete interface pinouts, etc.
The colophon for this manual reads
First Edition (March 1984)
So what is your time line for IBM only publishing this manual after the PC AT was cloned?
The first "100% Compatible" was the Compaq Portable in 1982. It wasn't the first "compatible" to market, but it claimed to be the first that hit the "100%" mark and validated the clone market.
Abstrd, but true according to what you're saying, if you can prove that I copied it. Now, assuming you did download and peruse the source code for Free_skype: fine. Now prove it.