What are the best hardcore technical blogs out there?

In the Bill Gates thread someone linked to a blog called nynaeve.net. It seems interesting and while I really do enjoy working with web technologies as well as Android I love reading about stuff that goes on deeper down the technical stack as well. Especially when it is about old school tech and the hacks they had to do to get great performance out of the limited hardware available at the time.

I used to have a list of blogs such as this in my Google RSS reader but forgot to make a copy when Google shut the service down. So which hardcore tech blogs does HN find the most interesting? I don't care about the tech stack (Linux, Windows, etc...) and the older the better.