The Windows 2000 and Windows XP virtual machines (VMs) upgraded without trouble, as did VMware Tools (which support varying screen sizes and access to the host file system, amongst other things).
For Ubuntu, I decided to try the internal upgrade to the current release (11.10) from 10.04 LTS. This took forever and didn't produce the desired result (a working system), so, because the Linux VMs aren't really where I do anything serious, I decided to do without Ubuntu; Debian will do just fine.
I was running Debian 5, but I spent quite a while trying to work out what release I had; it turns out that /etc/debian_version tells you the number, in my case 5.0.9. (I know Debian has amusing names for its releases; finding your current release's amusing name seems even more tricky).
Debian ran just fine. Unfortunately, the VMware Tools configuration failed, because, according to VMware, /usr/bin/gcc-4.3 wasn't a working compiler. This is of course twaddle.
I raised a service request with VMware (not the greatest of experiences, partly because I've never needed to use the web tool before, so it was quite unfamiliar) and the answer was that Fusion 4 doesn't support Debian 5 (you'll need to select Product Name Fusion, Product Release Version Fusion 4, and Partner Name Debian, then click on Update and View Results, then scroll down, phew); I should upgrade to Debian 6.
Well, as with Ubuntu, not a lot to lose, and I don't fancy debugging VMware's Perl configuration script. I installed Debian 6 (amd64) from scratch in a new VM, without difficulty (I noticed that I could have chosen Debian 5 as the host OS. Hah). The interesting part came with installing and configuring VMware Tools.
In order to run vmware-config-tools.pl, you need to install make, gcc and the Linux headers. The Linux headers (for 6.0.3) were linux-headers-2.6.32-5-common and linux-headers-2.6.32-5-amd64.
With that in place, the configuration went smoothly. The next hurdle was that the access to the host file system failed:
Starting VMware Tools services in the virtual machine: Switching to guest configuration: done Guest memory manager: done VM communication interface: done VM communication interface socket family: done Guest filesystem driver: done Mounting HGFS shares: failed Blocking file system: done VMware User Agent: done Guest operating system daemon: done Virtual Printing daemon: doneThis was because I'd forgotten to configure file sharing in Virtual Machine > Settings > Sharing.
During all this it had become obvious that I had keymap problems; not really surprising, I suppose, given that this is a Mac, and a Macbook at that.
I spent quite a while looking for a hint on the web (I couldn't find anything on VMware's site). There are suggestions for getting the console keymap right, but I don't expect to have to use \ or # at the console all that often. It turns out that under X Debian handles this perfectly via System > Preferences > Keyboard > Layouts; in Keyboard model select Apple and then Macbook/Macbook Pro. Job done!
The last piece of customisation before getting on with the job of installing GNAT was to get the mouse movement in the VM to be as close as possible to the native behaviour. In System > Preferences > Mouse > General, under Pointer Speed, I set Acceleration slightly faster and (counterintuitively) Sensitivity as low as possible.
So there we are, ready to roll!