By popular demand, here is a PDP-11 Live CD that is configured to auto-run the 'Dungeon' game (aka Zork) in a PDP-11 emulator. Well OK, when I say 'popular demand' I mean that a colleague of mine mentioned it in idle conversation...
I got the game files from here: http://www.dbit.com/pub/pdp11/rt11/games/
And if you don't know about the historic computer game of Zork, I suggest you have a read on wikipedia: http://en.wikipedia.org/wiki/Zork.
The previous PDP-11 Live CD that I made is great, but it only works with IDE CD-ROM drives, so you cannot use it if you have a SATA or USB CD-ROM. Which is a shame. So I wanted to make a version that doesn't rely on having CD-ROM drivers for DOS, since it's unlikely that I'd be able to support all of the different types of drive. I have tried to get my external USB CD-ROM drive to work under DR-DOS and found that I couldn't make it go.
So, for a few days I have been struggling to create an "El Torito" hard disk image, so that I could make a CD bootable version of a hard disk. I haven't gotten it to work yet. I even tried this (twice actually) by taking the HxD hex editor to an ISO file. I've given up for the time being, but I'll probably come back to it.
However, I can get floppy disk "El Torito" images to work perfectly, including the 2.88 Mb variety. That's how I got the previous Live CD to start (but I was only using a 1.44 Mb image that time). So with a bit of lateral thinking I realised that my PDP-11 disk compresses quite well. So I went off an got an UNZIP program for DOS, from here ... or to be specific, I downloaded unz600x3.exe from: ftp://ftp.info-zip.org/pub/infozip/msdos/.
This means that I can fit DR-DOS into a 2.88 Mb floppy image along with a compressed copy of the PDP-11 emulator and disk. Since everything is inside the 2.88 Mb image, we don't need to load CD-ROM drivers in DOS. It means that this bootable ISO will work with SATA and USB CD-ROM drives, it doesn't need the drivers since it's all done by the BIOS and the magic of El Torito. Cool.
[NOTE: I have since made a better version here.]
This ISO image of a bootable CD is the combination of two different threads I have been working on: how to make bootable CDs and how to set up RT-11 with Basic in SIMH, the PDP-11 emulator. This CD only works if you have an IDE CD-DROM drive though.
So I took the bootable CD image that I had already made and added SIMH for MS-DOS. Then I added my RT-11 / Basic-11 disk image. I set SIMH to start up automatically from a 16Mb RAM disk. It all seems to work. It is pretty fast in comparison to a real PDP-11! Because it is running from a DOS RAM disk, you get read/write access under RT-11 (until you switch the power off). But it does mean that you can't mess it up since you get a clean install each time you boot the CD. Oh, and if you're looking for a manual on Basic-11 I've posted some stuff here.
So... if you'd like to have a play with an ancient operating system, give it a try. Burn the ISO to a CD or boot it directly in Virtual PC or VirtualBox. I've tried it with as little as 32Mb RAM, and it works fine. When I get time, perhaps I'll do an ancient Unix Live CD as well.