Excited by last night’s success at turning my internet tablet into a VAX I thought I’d see if it could pretend to be an IBM mainframe, and in particular a System/370 running 1970s vintage IBM VM. I also knew I could fit this operating system on the spare SD card I had which is only 128MB. And will have to wait until I get a spare 1GB or 2GB card before trying out booting OpenVMS under SimH. And besides which I have observed previously that VM when not running a task doesn’t appear to access disk much if at all, and so it should be kind to flash storage.

And so I downloaded a copy of the source for the IBM mainframe emulator Hercules, untarred it inside the scratchbox, and ran configure followed by make. Once again no issues and so I followed this by a ‘make install’, and then went on to locate the Hercules files installed into the scratchbox under ‘/usr/local’, tarred them up and copied this across to the N800. I then took an existing Hercules config file and tweaked it for the N800 by commenting out any devices I didn’t need, and updating the file paths to the virtual DASD containing IBM VM/370 R6 which would be located on ‘/media/mmc1/’ (128Mb SD card in the external slot).

Hercules started up without any problems, VM IPLed (Initial Processor Load – IBM parlance for ‘boot’) and the CPU was busy for a while as VM started up. Following this I was able to fire up an IBM 3270 terminal emulator on my Mac, observe the connection in Hercules, and get a VM logon screen on the 3270. I then tried to logon but the 3270 had lost connection to Hercules, which I ‘m pretty confident was a result of the N800’s WLAN power saving mode kicking in (outbound connections turn it off, but not inbound it seems). To complete this handheld mainframe configuration I really need to get TN3270 or similar built for Maemo so that I can fire up a local 3270 terminal.

I still can’t believe that I have an IBM mainframe running in the palm of my hand. It’s pretty crazy… For the uninitiated IBM were doing virtualisation with VM _way_ before the likes of VMware and Xen etc. And even with this antique pre-software-copyright version you can run a whole new copy of VM inside one virtual machine, and inside that run another copy, and so on. Or inside a virtual machine run another IBM operating system such as MVS. And if you are licensed for a more recent copy of VM can even get Linux running inside virtual machines. It’s pretty cool and each logged in user gets an entire (virtual) IBM mainframe at their disposal.

I think I’ll order that bigger SD card tomorrow so I can give OpenVMS a go under SimH. And should also now look into how to package Maemo SimH and Hercules builds up into ‘.deb’ files.