Questions tagged [pdp-7]
For questions about the DEC PDP-7 minicomputer.
6
questions
33
votes
2
answers
5k
views
Why was UNIX never backported to the PDP-7?
Originally, UNIX was written in PDP-7 assembly, and then in PDP-11 assembly, but then when UNIX V4 began to be re-written in C in 1973 and was run mostly on the PDP-11.
So far as I can tell, there ...
- 38k
18
votes
2
answers
3k
views
What is the instruction set of the PDP-7?
The PDP-7 was a bookshelf-sized "minicomputer", with keyboard, magnetic and paper tape and printer I/O. According to Wikipedia, the first version of UNIX (then named Unics) was programmed in assembly ...
- 18.2k
14
votes
2
answers
1k
views
Null-terminated strings on the PDP-7?
I came across a post that states that Unix uses null-terminated strings, ASCIZ, because it was a feature of the PDP-7. This triggered my reading on the CIS instructions in the PDP-11, but these were ...
- 19.1k
9
votes
2
answers
545
views
Why do the later 18 bit PDPs include both ones' and two's complement?
The PDP-1 is a ones' complement machine, and does some checks to make sure you (almost) never get negative zero. I'm struggling to think why anyone would want ones' complement arithmetic, but it was ...
- 38k
4
votes
0
answers
278
views
What does this image in Space Travel represent?
I was touching up the Space Travel article on the Wiki and realized no one had answered a question I posted some time ago. I suspect someone here knows the answer.
This image is used in the infobox to ...
- 19.1k
3
votes
2
answers
351
views
Is it possible to get a pdp7 [closed]
Is it possible to get an original DEC pdp-7, if so how much would it be? I've looked around the internet, but I'm not finding anything.
user11220