The "Make Better Software" series [0] which follows Joel Spolsky and his company Fog Creek on various aspects of bootstrapping and running a software company.
It's not a documentary but the BBC drama 'Micro Men' is very good and AFAIK mostly historically accurate.
It's about the battle between Clive Sinclair (of Sinclair Spectrum fame) and Chris Curry (founder of Acorn Computers, the progenitor of ARM) for dominance in the 80's UK home computer market.
Alan Kay talks about the innovations that came out of PARC. I liked it because it confirmed my belief that true industry changing innovations are rare.
‘General Magic’ was pretty interesting. It was especially fun to learn about all the influential companies and technology people that emerged from that one company. It definitely re-enforces the idea that sillicon valley isn’t just about a handful of big companies but a community of folks that influence each other. At least at the time of the documentary’s story.
Released for free after the DVDs sold out: http://www.bbsdocumentary.com/order/
https://en.wikipedia.org/wiki/BBS:_The_Documentary