Category Archives: computer history

playing with simh: running unix v5

One of the thing in computer history that I’m fascinated is unix. It’s one of the most important Operating System, that most people today didn’t use. And already have many concept, that is added much later time, in commercial PC operating system. And it already have the concept of code sharing, before Free Software or Open Source exist.

Pretty all of the resource is from this article. Except my opinion

To simplify the step.

1) download
2) unzip everything
3) create a pdp11.ini

set cpu U18
attach rk0 unix_v5_rk.dsk

3) then run the pdp11 emulator. This I assume that you installed simh already.
note: on windows you might need to copy the pdp11 emulator, from simh, to the same folder as the unix.

you should see the following. prompt

PDP-11 simulator V3.7-0
Disabling XQ

just type unix

which shows


, then type root. Now you should see the familiar root shell.

But note it’s not a unix as we know on linux, or bsd, or any modern unix(i think), for example there is no cd, it’s chdir. And many thing is not there, or very different.

But that’s unix. What cool, is that, it contain the source code for unix as well. And amazing how to stuff the OS, in a relatively small package

playing with simh: running altair 8800

One of the consequence of reading “Fire In The Valley”, is the urge to run an Altair, even an emulator is good enough.

Last post involve, installing simh on ubuntu. And links to download.

The first part of my altair 8800, is to get the os and software to run. You can get the software of altair here. I’m not sure, how to run the original 8800, which uses the 8080 processor. But the z80 version of the emulator works.

The links have the have the emulator, and cp/m2.2 bundled together. And other software. Since I already have the emulator, just download cp/m2.2 .

This is the cp/m shell, aka the dos shell

To run it on ubuntu, unzip the cp/m 2.2 folder. And at the same directory, run the emulator. That is open terminal type, altairz80. It will open the emulator. Then under the sim> shell, type “do cpm2”.

On windows, just unzip the cpm2.2 zip file, into a directory, and put the emulator there too. To run the emulator, click on the emulator, then type “do cpm2”

And well play around, with basic

playing with simh: aka fascinated with computer history

After reading “Fire In The Valley”. I wanted to see how an Altair work. Since I am not rich, so I can’t get my hand on an Altair. The next best thing is an emulator. Such an emulator exist for quite sometime, and more importantly it’s open source, and available on Ubuntu.

Simh is not just an emulator, it’s actually a set of emulator, that emulate a number of ancient machine, that I wanted to get a hand on. Such as a PDP-11, which is used to run the first UNIX.

And to install it on ubuntu is again a matter of

sudo apt-get install simh

What make it interesting is that, each machine emulated is represented as an executable, so calling an emulator, is a matter of calling the right program, for example, running an altair is a matter, of running the program, altair on linux, altair.exe on windows.

And there is a windows version too. One reminder, it only provide the emulator not the os and program.

The links provide the emulator, source code, and windows executable.

There is links to the program that are needed to make the emulator useful

Fire In The Valley, a very good book

I’m currently in the Main Library of University Of Malaya. One of the best things here is that, sometime there is treasure in this library, and no one bother to borrow it. Most just get references, past exam papers, academic books.

Treasure, the book “Fire In The Valley: The Making Of Personal Computer” is such a treasure. It have inspired, the film “Pirates Of Silicon Valley”. But really, The book is a lot more.

It describe, on the age of computer hobbyist, the MITS, and some old microcomputer company, that don’t exist anymore, such as IMSAI.

I won’t all it a text book, but still it is an interesting read for computer history buff like me.