Posted by under Android,Emulation,OpenVMS,SIMH,VAX on September 16 2015, 0 comments

I’ve thought long and hard on this one: SimH runs under Linux, and Android is based on Linux, so can you run SimH, and thence a simulation of a VAX, on an Android phone/tablet?

Well, obviously you can, but it really is a bit of a fiddle. There is an Simh Android App to do this “easily”, but you have to pay for it and the company’s own terminal emulator, and I couldn’t get it to work on any of my devices.

Firstly, you’ll need a rooted device. Root your Android phone/tablet at your peril. I’m not even going in to how to do this.

You’ll also need an SSH Server (QuickSSHd), and Busybox.

Next, I’d recommend setting your VAX simulation up using a fairly fast computer, as doing it on a tablet/phone will take a very long time.

For this, look at

Note: I can’t link to the OpenVMS ISO, or any licenses. You’ll have to get these through the Hobbyist licensing program.

I wouldn’t bother including any networking tools, as they just won’t work, but just carry on with the rest of the installation (including the licenses), until it is done. Add a user too. And remember the passwords you use! I forgot and had to start this all over again.

I actually cheated a lot at this stage and used a blindingly fast Win8.1 machine rather that one of my Raspberry Pis. Mainly as I wanted to do this in an hour, and not half a day.

At the end of that, you should have a d0.dsk image that can be copied to the Android device.

You’ll need a copy of the vax binary and some other files. I’ve popped copies of what you need at (but we’ll be wgetting to that – or even from that – later).

Note: The precompiled “vax-android” binary came from, but as that site seems to be on a Dynamic DNS address that isn’t always available, I’ve copied it to the above location and renamed it. You could take the time to cross-compile it yourself, but, well, meh.

Anyway, the device I’m using to host this little experiment is an aging Samsung Galaxy Europa GT-I 5500, which I have said bad things about elsewhere in the past. There are a couple of reasons for using this:

  • The phone is pretty much knackered anyway, after the abuse it has suffered over the last couple of years,
  • It can act as a WiFi hotspot,
  • It is smaller than most modern phones, and as we’re going from Big Iron to a small device, it seems appropriate,
  • It runs a sufficiently ancient version of Android that there won’t be any issues with the cock-eyed SDcard permissions that have plagued later versions.

So while most people are looking to exploit the features Android 5.1 on large tablet screens, I’m looking at Android 2.2 on a four year old cheap phone.  This, to be honest, is not usual for me.

Anyway, you’ll probably want to install this to your SD card, so somehow copy the d0.dsk image on to the card in a directory called “simh”. I did this by popping the card into my windows box and copying it that way – just to save time.

On my install this ended up being located at /sdcard/simh

So, pop the card back into the phone, fire up QuickSSHd and connect to it.

# cd /sdcard/simh
# wget
Connecting to (
ka655x.bin           100% |*******************************|   128k  0:00:00 ETA
# wget
Connecting to (
nvram.bin            100% |*******************************|  1024   0:00:00 ETA
# wget
Connecting to (
vax-android          100% |*******************************|   393k  0:00:00 ETA
# wget
Connecting to (
vax-android.txt      100% |*******************************|   876   0:00:00 ETA
# mv vax-android.txt vax-android.ini
That was a kludge as my server blocks the downloading of .ini files
# ls

So far so good… but Android doesn’t like running binaries from an SD card, so we’d better put them somewhere else.

# mkdir /data/simh
# cp vax* /data/simh
# cd /data/simh

And we can run it…

# ./vax-android