Virtual Machines

One of my recent investigations has been into using Virtual machines (tried both Xen and VMware) to consolidate some services and get rid of some ancient stand alone windows machines.

I've now got rid of three windows machines and replaced them by two VMware machines. The host is a Debian etch box and the guest is a windows XP machine.

One of the key issues for what I've wanted to do is providing the right hardware to the guest machines. In particular, one of them needs a parallel port for a dongle and three serial ports for modems and a data logger. The parallel port wasn't a problem as VMware can pass through the native port on the host machine. For the serial ports one of the added complications was that two of them need to be at quite a distance from the host. So, I've got hold of some Perle IOLan DS single port terminal servers. These have a mode of operation called Trueport where they can provide a virtual serial port to a remote computer. If you combine these with PoE splitter units (I've got the ones by Level One - very nice little boxes that will give you 5, 7.5, 9 or 12 V out to power your device) then you get a remote serial port anywhere on your network.

So far I've got this method working for the data logger and one of the modems. The other modem is being a little more stubborn. It would appear that there's some kind of issue with windows dialup networking and this way of connecting a modem that isn't entirely happy. So for now, the dialup networking modem is connected to the serial port on the host which is being passed through to the guest.