Steve Bellovin on Nostr: npub1drqhe…wy62j npub186sn5…l54uq The 3B20 was itself an odd computer. It was a ...

npub1drqhezshdhrt2knhuxg696qv67l68d6sqx83fvcrmech59zdpqts4wy62j (npub1drq…y62j) npub186sn5wsyd3nkatggdesfu8u8nl4mehjgfrpxzf8afu2uhwdlux9qrl54uq (npub186s…54uq) The 3B20 was itself an odd computer. It was a VAX 11/780-class machine intended for telco central office use. We had the 3B20S, the simplex processor model. But if you opened up one of the cabinets, you could see its CO roots—there were four large 12V lead-acid batteries, to produce the -48V DC that CO gear ran on. The 3B20D ran DMERT (https://en.wikipedia.org/wiki/Multi-Environment_Real-Time), a real-time Unix variant. I've read about it but never played with it.