A Hello-World program in Unix V6 on the SIMH simulator

In my previous post I've talked about how to get Unix Version 6 to run in the SIMH PDP-11 simulator. Now that you have Unix V6 up and running, there is some nice hacking you can do. Here's the classic "Hello World" program in retro '70s style.

System setup

At this point you should have successfully started up and logged in as root into your Unix V6 system on the SIMH pdp11 simulator. For instructions on how to do that, read here. Once everything is correct, you should be greeted by the root prompt "#".

This where the times of ed

So in Unix V6 we're actually in a pre vi and emacs world. So the standard editor that was available at that time was ed (a so called line editor) which you will find even less intuitive to use than vim or emacs.

So here's how to write a Hello-World C program with ed and compile with cc:

Running Unix V6 in the SIMH PDP-11 simulator

!!! Attention: this article (and in fact my whole blog) have moved to site:
http://thecsbox.com/2013/05/09/running-unix-v6-in-the-simh-pdp-11-simulator/ !!!

Just to live out my inner geek, I was experimenting with getting antique Unix versions to run in a simulator recently (admittedly this was also for a class project). I was using the simulators from the SIMH project and got the famous Unix Version 6 running on a PDP 11 simulator.

Related Articles:
Unix in a Nutshell
Prepping for Coding Interviews - Part I
Reading Notes: Ethernet paper by Metcalfe and Boggs

Unix in a Nutshell

!!! Attention: this article (and in fact my whole blog) have moved to site:
http://thecsbox.com/2013/05/04/unix-in-a-nutshell/ !!!

I recently read the original paper on Unix: “The Unix Time-Sharing System” (Ritchie, Thompson, 1974), and I’ve long been a Unix and Linux fan, so I thought I’ll take this occasion to write an article about what I consider are Unix’s main contributions and what makes it so interesting.

A little bit of history first...

Unix was written by Dennis Ritchie and Ken Thompson in the famous AT&T Bell Labs during the 1970s. The original hardware they used was a PDP-7 and the first version was written in assembly. This may sound incredible today, but at that time not many high level languages existed and it was natural to write something as complex and performance sensitive as an operating system in assembly. Unix is also being accredited for being the first widespread general-purpose operating system. While operating systems existed before Unix, they were usually produced by the hardware manufacturer and were thus very heterogeneous. The idea of having a separate OS provider and to have one OS support different hardware did not really exist before Unix.

Contributions of Unix

I consider the following points the most important contributions of Unix:

• file system and file I/O
• greatly assisted the widespread use of C
• focus on simplicity and elegance in its design