Technical history or "internal history" is great. Regular historians writing "external history" of computing tend to focus on certain topics, such as business and economic issues, politics, personalities, or occasionally social impact, while omitting the details of the technology itself - which are often of great interest to practitioners, and which help us understand why things happen to work the way they do.
Of course people who experienced things firsthand often have interesting personal as well as technical insight. CHM's oral histories often provide a combination of both. I also always enjoy: