Real hardcore, I'd delve into archives of technical publications from Bell Labs, Berkeley Lab, etc.
https://commons.lbl.gov/display/itdivision/Berkeley+Lab+Publ...
https://archive.org/details/bstj-archives
This report from BBN is a pretty great example of the level of detail and insider history that can be discovered. I really wish there was more stuff like this extant.
http://walden-family.com/bbn/bbn-print2.pdf
Youtube is of course an endless treasure trove as well. From The MIT Vault is a bit of a time machine unto itself. And you can always find the random Netscape Communicator conference keynote from 1997 with a young Marc Andreessen. As well as oral histories and product demos like "RAND Corp presents the Graphics Rocket!" on the Computer History Museum channel ;)
https://www.youtube.com/user/FromTheVaultofMIT
https://www.youtube.com/user/ComputerHistory/videos
On the softcore front. I am thinking of revisiting Daniel Boorstin's "Knowledge Trilogy". Completely out of vogue in our age of Taleb, Hariri and Gladwell. Probably chock full of cringe inducing corniness. But I remember loving the vivid writing style as a kid.