ALSA doesn't use /dev names for audio devices (yes, it accesses them that way, but the naming is different).

In your "config=" line in the midi setion, you should enter the port number your sequencer is located at. 65:0 is the default, I have no idea how your card's driver registers itself. Try 32:0, 64:0 or 128:0, or 65:1.

Well, there is even a command to list all available devices and their port numbers... try googling for "aconnect" or something like that, I don't remember right now, and I can't check myself (at work 😀 )

aconnect -o

Or, if you have it installed:
pmidi -l

I like pmidi's listing a little more... less confusing.

Thanks guys. Sometimes Gentoo seems like a game of Zork or whatever. Get a hint, and eventually find the treasure. Both aconnect and pmidi showed no midi clients at all. Some googling indicated that I had to build the snd-virmidi module.

After the build and reboot, I found out after some trial and error that the correct initialisation command for my system is...
modprobe snd-virmidi index=1

aconnect and pmidi showed 4 ports 72...75. So I set ~/.dosboxrc to

device=alsa
config=72:0

and it finally works. One last question. I vaguely remember reading somewhere in the docs about needing specific libs to do a screen cpature. For the life of me, I can't find that item now, when I really want it. What libs are required (on linux)?

I believe libpng is required (someone do correct me if I'm wrong...), and you're likely already set to go, since I would imagine it being a dependancy for some other program you've already emerged.

Personally, when I do screen captures, I just use 'import' which is part of the imagemagick package.

I'm pretty sure it's libpng as well.