Wed 15 Oct 2008
Pleased with my initial success with coLinux, I set out to add the finishing touches.
I’ve gone back and forth on the network configuration, trying e.g. to carefully follow Bebbo’s config example. It didn’t work for me. There seem to be issues running TAP on Vista, and bridging with my Wireless LAN interface caused the WLAN connection to start acting up. I also tried the Microsoft Loopback adapter, but no joy. I finally figured out that just using slirp with the following (recommended) setting:
(upate: I made a last minute change that proved wrong. This is what works.)
worked just fine. The only problem was that I thought I had to set the DISPLAY variable to the (dynamically configured) IP address of my laptop. But looking at the auto-generated setting for eth0 in /etc/network/interfaces, I realized that slirp had assigned an IP address for my laptop, as seen from the coLinux end:
iface eth0 inet static
The “gateway” address was the one I needed, so I could just hardcode the following in my .bashrc:
Xming is said to be a lighter and better X-Windows server than Cygwin X, so I set out to change. No major issues, except that I had a very hard time figuring out how to get it do display Swedish characters. I’d suffered this in the coLinux console too, but that was ok, since I intended to jump into X as soon as possible.
Fixing the language support in the console was … uhm, not so easy, but I’ll attribute that to my being sorely out of practice on linux admin chores. Googling indicated that the cure was
apt-get install locales
apt-get install console-data
Close, but no cigar. I also had to do
apt-get install kbd
Now, I had Swedish characters in the console, but not in X. Finally, I found this post (in Swedish), suggesting that it’s a bug in Xming’s definition of the Swedish layout. Specifying Finnish layout instead solved the problem.
The command line for Xming now looks like this:
exec0="c:\Program Files\Xming\Xming.exe -multiwindow -clipboard -silent-dup-error -xkbmodel pc105 -xkblayout fi"
I also tried setting the environment variable COLINUX_NO_SMP_WORKAROUND=Y, to get coLinux to use both cores. I was disappointed to see that
erl -smp still only saw one CPU. Apparently, coLinux makes internal use of SMP, but makes it look like a single-core system for the linux applications. My win32 version of Erlang does see both CPUs, though.
Also, it seems as if erlang under coLinux suffers from the same problem as under Win32 – erlang:now() doesn’t have sufficient resolution:
Eshell V5.6.4 (abort with ^G)
1> [erlang:now() || _ <- lists:seq(1,10)].
Note how it increments by 1 usec each time? On my other laptop running Ubuntu, the diff is ca 12 usec between each (by definition, erlang:now() always steps up at least 1 usec). I wish I could say that my Vista laptop is ~10x faster, but that’s not it. Apparently, coLinux doesn’t offer a gethrtime(). gethrvtime() also seems to be missing, and configure reports clock_gettime() as “not stable”. No disaster, perhaps, but a good erlang:now() is often useful.