But now to the installation: I show it with the 64bit version of Debian Lenny.

After the installation of Lenny, install the custom Xen kernel and Xen-Tools:

apt-get install xen-linux-system-2.6.26-1-xen-amd64 xen-utils-3.2-1 lvm2 python-xml xen-tools

In order to bridge the virtual network devices of your guests to the host system, you need to edit the configuration file /etc/xen/xend-config.sxp

This part is relevant:


##
# To bridge network traffic, like this:
#
# dom0: ----------------- bridge -> real eth0 -> the network
# |
# domU: fake eth0 -> vifN.0 -+
#
# use
#
(network-script network-bridge)
#
# Your default ethernet device is used as the outgoing interface, by default.
# To use a different one (e.g. eth1) use
#
# (network-script 'network-bridge netdev=eth1')
#
# The bridge is named xenbr0, by default. To rename the bridge, use
#
# (network-script 'network-bridge bridge=‘)
#
# It is possible to use the network-bridge script in more complicated
# scenarios, such as having two outgoing interfaces, with two bridges, and
# two fake interfaces per guest domain. To do things like this, write
# yourself a wrapper script, and call network-bridge from it, as appropriate.
#
#(network-script network-dummy)


You must comment “(network-script network-dummy)” out as seen in the listing and remove the comment before “(network-script network-bridge)”

Now you can boot into your freshly installed Xen-Linux:
shutdown -r now

To check that everything works as expected run:

xm list Xm stands for Xen-management, a tool to manage your guest machines.

Is should say something like this:


olymp:~# xm list
Name ID Mem VCPUs State Time(s)
Domain-0 0 3242 4 r----- 266.8


Domain-0 is your host system and you haven’t created any guests yet.

You can do that very easily with the xen-tools, that you’ve already installed. You can set your default preferences for it very easily in the file /etc/xen-tools/xen-tools.conf. To use Debian Lenny 64bit as default guest, use the following configuration:

1. ##
2. #  /etc/xen-tools/xen-tools.conf
3. ##
4. #
5. #  This is the global configuration file for the scripts included
6. # within the xen-tools package.
7. #
8. #  For more details please see:
9. #
10. #        http://xen-tools.org/
11. #
12. ##
13.  
14.  
15. ##
16. #
17. # File Format
18. # ———–
19. #
20. #  Anything following a ‘#’ character is ignored as a comment.
21. #
22. #  Otherwise the format of this file "key = value".  The value of
23. # any keys in this file may be constructed via the output of a command.
24. #
25. #  For example:
26. #
27. #         kernel = /boot/vmlinuz-`uname -r`
28. #
29. ##
30.  
31.  
32.  
33. #
34. ##
35. #  Output directory for storing loopback images.
36. #
37. #  If you choose to use loopback images, which are simple to manage but
38. # slower than LVM partitions, then specify a directory here and uncomment
39. # the line.
40. #
41. #  New instances will be stored in subdirectories named after their
42. # hostnames.
43. #
44. ##
45. dir = /home/xen
46. #
47.  
48. #
49. ##
50. #
51. # If you don’t wish to use loopback images then you may specify an
52. # LVM volume group here instead
53. #
54. ##
55. # lvm = skx-vg
56.  
57.  
58. #
59. ##
60. #
61. #  Installation method.
62. #
63. #  There are four distinct methods which you may to install a new copy
64. # of Linux to use in your Xen guest domain:
65. #
66. #   - Installation via the debootstrap command.
67. #   - Installation via the rpmstrap command.
68. #   - Installation via the rinse command.
69. #   - Installation by copying a directory containing a previous installation.
70. #   - Installation by untarring a previously archived image.
71. #
72. #  NOTE That if you use the "untar", or "copy" options you should ensure
73. # that the image you’re left with matches the ‘dist’ setting later in
74. # this file.
75. #
76. #
77. ##
78. #
79. #
80. # install-method = [ debootstrap | rinse | rpmstrap | copy | tar ]
81. #
82. #
83. install-method = debootstrap
84.  
85. #
86. # If you’re using the "copy", or "tar" installation methods you must
87. # need to specify the source location to copy from, or the source
88. # .tar file to unpack.
89. #
90. # You may specify that with a line such as:
91. #
92. # install-source = /path/to/copy
93. # install-source = /some/path/img.tar
94. #
95. #
96.  
97. #
98. ##
99. #  Command definitions.
100. ##
101. #
102. # The "rinse", and "rpmstrap" commands are hardwired into
103. # the script, but if you wish to modify the commands which are executed
104. # when installing new systems by a "copy", "debootstrap", or "tar" method
105. # you can do so here:
106. #
107. # (This allows you to install from a .tar.bz file, rather than a plain
108. # tar file, use cdebootstrap, etc.)
109. #
110. # install-method=copy:
111. # copy-cmd = /bin/cp -a $src/* $dest
112. ##
113. #install-method=debootstrap:
114. debootstrap-cmd=/usr/sbin/debootstrap
115. #
116. # install-method=tar:
117. # tar-cmd  = /bin/tar –numeric-owner -xvf $src
118. #
119. #
120.  
121.  
122.  
123. #
124. ##
125. #  Disk and Sizing options.
126. ##
127. #
128. size   = 4Gb      # Disk image size.
129. memory = 256Mb    # Memory size
130. swap   = 256Mb    # Swap size
131. # noswap = 1      # Don’t use swap at all for the new system.
132. fs     = ext3     # use the EXT3 filesystem for the disk image.
133. dist   = lenny     # Default distribution to install.
134. image  = sparse   # Specify sparse vs. full disk images.
135.  
136. #
137. #  Currently supported and tested distributions include:
138. #
139. # via Debootstrap:
140. #
141. #  Debian:
142. #   sid, sarge, etch, lenny.
143. #
144. #  Ubuntu:
145. #   edgy, feisty, dapper.
146. #
147. # via Rinse:
148. #   centos-4, centos-5.
149. #   fedora-core-4, fedora-core-5, fedora-core-6, fedora-core-7
150. #
151. #
152.  
153.  
154.  
155. ##
156. # Networking setup values.
157. ##
158.  
159. #
160. # Uncomment and adjust these network settings if you wish to give your
161. # new instances static IP addresses.
162. #
163. # gateway   = 192.168.1.1
164. # netmask   = 255.255.255.0
165. # broadcast = 192.168.1.255
166. #
167. # Uncomment this if you wish the images to use DHCP
168. #
169. dhcp = 1
170.  
171.  
172. ##
173. # Misc options
174. ##
175.  
176. #
177. # Uncomment the following line if you wish to disable the caching
178. # of downloaded .deb files when using debootstrap to install images.
179. #
180. # cache = no
181. #
182.  
183. #
184. # Uncomment the following line if you wish to interactively setup
185. # a new root password for images.
186. #
187. passwd = 1
188.  
189. #
190. # If you’d like all accounts on your host system which are not present
191. # on the guest system to be copied over then uncomment the following line.
192. #
193. # accounts = 1
194. #
195.  
196. #
197. # Default kernel and ramdisk to use for the virtual servers
198. #
199. kernel      = /boot/vmlinuz-`uname -r`
200. initrd      = /boot/initrd.img-`uname -r`
201.  
202. #
203. #  The architecture to use when using debootstrap, rinse, or rpmstrap.
204. #
205. #  This is most useful on 64 bit host machines, for other systems it
206. # doesn’t need to be used.
207. #
208. arch=amd64
209. #
210.  
211. #
212. # The default mirror for debootstrap to install Debian-derived distributions
213. #
214. mirror = http://ftp.de.debian.org/debian/
215.  
216. #
217. # A mirror suitable for use when installing the Dapper release of Ubuntu.
218. #
219. # mirror = http://gb.archive.ubuntu.com/ubuntu/
220.  
221. #
222. #  If you like you could use per-distribution mirrors, which will
223. # be more useful if you’re working in an environment where you want
224. # to regularly use multiple distributions:
225. #
226. # mirror_sid=http://ftp.us.debian.org/debian
227. # mirror_sarge=http://ftp.us.debian.org/debian
228. # mirror_etch=http://ftp.us.debian.org/debian
229. # mirror_dapper=http://archive.ubuntu.com/ubuntu
230. # mirror_edgy=http://archive.ubuntu.com/ubuntu
231. # mirror_feisty=http://archive.ubuntu.com/ubuntu
232. # mirror_gutsy=http://archive.ubuntu.com/ubuntu
233.  
234.  
235. #
236. #  Filesystem options for the different filesystems we support.
237. #
238. ext3_options   = noatime,nodiratime,errors=remount-ro
239. ext2_options   = noatime,nodiratime,errors=remount-ro
240. xfs_options    = defaults
241. reiser_options = defaults
242.  
243. #
244. #  Uncomment if you wish newly created images to boot once they’ve been
245. # created.
246. #
247. boot = 1
248.  
249.  
250. #
251. #  If you’re using the lenny or later version of the Xen guest kernel you will
252. # need to make sure that you use ‘hvc0′ for the guest serial device,
253. # and ‘xvdX’ instead of ’sdX’ for serial devices.
254. #
255. #  You may specify the things to use here:
256. #
257. serial_device = hvc0 #default
258. # serial_device = tty1
259. #
260. disk_device = xvda #default
261. # disk_device = sda
262. #
263.  
264.  
265. #
266. #  Here we specify the output directory which the Xen configuration
267. # files will be written to, and the suffix to give them.
268. #
269. #  Historically xen-tools have created configuration files in /etc/xen,
270. # and given each file the name $hostname.cfg.  If you want to change
271. # that behaviour you may do so here.
272. #
273. #
274. # output    = /etc/xen
275. # extension = .cfg
276. #
277. Download this code: xen-tools.conf

Now you can use:

xen-create-image --hostname test1 --role=udev

to install a new Debian Lenny as guest system. If everything went as it should, you should see your new client after that in “xm list”. Otherwise it doesn’t show up and you can try to manuelly create it with “xm create ” to see the error.

By the way “–role=udev” is needed, to install the package udev automatically in the guest. Without it, you can’t use ssh with your new guest and get the following error if you try to log in:


PTY allocation request failed on channel 0
stdin: is not a tty


If you use images for your guest (like shown here) you get very fast to the standard loopback limit of Debian Lenny. With that limit you can’t create more than 3 or 4 guests. It’s recommended to edit the file /etc/modprobe.d/local-loop (or create it) to adjust that limit:


options loop max_loop=64


Some more basics besides “xm list”: You can use “xm top” to monitor the activity of your guests (like top for processes). You can start, reboot and shutdown a guest with “xm start “, “xm reboot ” and “xm shutdown “.
You can enter a guest system directly with “xm console “. To exit the guest and go back to Dom0 use ctrl+]

For more commands you should read “xm help”

Screenshot of extented screen with taskbar

You can clearly see which programs are running and you have a good overview. The other goodies like cpu load display and the clock is also very practical.

The global configuration file /etc/screenrc already has some minor tweaks (Depending on your distribution). If you only want the taskbar for a particular user, than the local .screenrc in your home directory is the file to edit.

The heart of my screen configuration is:


backtick 1 0 0 /usr/bin/cpuusage
hardstatus alwayslastline
hardstatus string '%{= kG} %{G}%H %{g}[%= %{=kw}%?%-Lw%?%{r}(%{W}%n*%f%t%?(%u)%?%{r})%{w}%?%+Lw%?%?%= %{g}] %1`%% CPU %{W}%c %{g}’


With “backtick” a command-directive (1 here - must be a number) is noted. The “0 0″ then means that whenever a new output from the program is produced, screen stores the last line of output. “Hardstatus” is for the taskbar and each % directive is for special purposes. With `% 1 for example the last line of the backtick command is printed. For all the other directives better read the GNU screen-manpage

The cpuusage-script looks like this:

1. #!/bin/bash
2. awk ‘BEGIN {file = "/proc/stat";while (a==a) {getline < file;u=$2-up;s=$3-sp;n=$4-np;i=$5-ip;printf ("%2.1f\n"),(u+s)/(u+s+n+i)*100;up=$2;sp=$3;np=$4;ip=$5;close(file);system("sleep 1")}}’
3. Download this code: cpuusage

This awk-oneliner uses the information from /proc/stat to calculate the cpuload for one second. That is supported on all unixes with proc support (Mac OS X has no proc).

What’s missing now, is dynamic window titles. In the previous configuration, all titles are set to “n * bash”, we had to change the titles manually.

With a special escape-sequence, the title can be set from the console. The screen manpage explains the procedure:


The default name for all shell windows can be set with the "shelltitle"
command in the .screenrc file, while all other windows are created with
a "screen" command and thus can have their name set with the -t option.
Interactively, there is the title-string escape-sequence
(kname\) and the “title” command (C-a A). The former can be
output from an application to control the window’s name under software
control, and the latter will prompt for a name when typed. You can
also bind pre-defined names to keys with the “title” command to set
things quickly without prompting.

Finally, screen has a shell-specific heuristic that is enabled by set-
ting the window’s name to “search|name” and arranging to have a null
title escape-sequence output as a part of your prompt. The search por-
tion specifies an end-of-prompt search string, while the name portion
specifies the default shell name for the window. If the name ends in a
‘:’ screen will add what it believes to be the current command running
in the window to the end of the window’s shell name (e.g. “name:cmd”).
Otherwise the current command name supersedes the shell name while it
is running.

Here’s how it works: you must modify your shell prompt to output a
null title-escape-sequence (k\) as a part of your prompt.
The last part of your prompt must be the same as the string you speci-
fied for the search portion of the title. Once this is set up, screen
will use the title-escape-sequence to clear the previous command name
and get ready for the next command. Then, when a newline is received
from the shell, a search is made for the end of the prompt. If found,
it will grab the first word after the matched string and use it as the
command name. If the command name begins with either ‘!’, ‘%’, or ‘^’
screen will use the first word on the following line (if found) in
preference to the just-found name. This helps csh users get better
command names when using job control or history recall commands.

My shellprompt looks like this:


server1 pastacode #


That means, all my commands are typed in after the #. So, I have to add this to my .shellrc :


#dynamic title
shelltitle '# |bash'


Screen now looks for a # when it gets the escape-sequence. “| Bash” means that the default title is “Bash”. We now only need the escape sequence in our promt; that can be customized (in Bash) with the PS1 variable. To do this we will either edit the /etc/bashrc (for any user) or the local .bashrc in our home directory. My .bashrc looks like this:

1. export EDITOR=/usr/bin/vi
2.  
3. # Set the screen title
4. case $TERM in
5. screen*)
6. # This is the escape sequence ESC k \w ESC \
7. #Use path as titel
8. #SCREENTITLE=’\[\ek\w\e\\\]‘
9. #Use program name as titel
10. SCREENTITLE=‘\[\ek\e\\\]‘
11. ;;
12. *)
13. SCREENTITLE=”
14. ;;
15. esac
16.  
17.  
18. PS1="${SCREENTITLE}${PS1}"
19. Download this code: bashrc

The PS1 is altered to add the screen escape-sequence, but only when we are in screen. In my file, you can actually choose between two versions: either the current path is the dynamic title, or the program name, although I prefer the latter. Unfortunately viewing both seems to be not a trivial thing.

So I hope the whole thing works for you - for suggestions, better ideas - write a comment!

Last but not least my complete .screenrc:

1. #no bells and startup messages
2. startup_message off
3. vbell off
4.  
5. #10000 lines scrollback buffer
6. defscrollback 10000
7. #no login
8. deflogin off
9.  
10. # Default shell
11. shell bash
12.  
13. #Timeout for displaying messages
14. msgwait 1
15. activity "         Activity has appeared in window      %n - %t"
16.  
17. #taskbar
18. backtick 1 0 0 /usr/bin/cpuusage
19. hardstatus alwayslastline
20. hardstatus string ‘%{= kG} %{G}%H %{g}[%= %{=kw}%?%-Lw%?%{r}(%{W}%n*%f%t%?(%u)%?%{r})%{w}%?%+Lw%?%?%= %{g}] %1`%% CPU %{W}%c %{g}’
21.  
22. #dynamic title
23. shelltitle ‘# |bash’
24.  
25. #When your ssh connection dies, screen is autodetached
26. autodetach on
27.  
28. #Nice 256 term colors
29. attrcolor b ".I"
30. termcapinfo xterm ‘Co#256:AB=\E[48;5;%dm:AF=\E[38;5;%dm’
31. Download this code: screenrc

And the cpuusage script:

1. #!/bin/bash
2. awk ‘BEGIN {file = "/proc/stat";while (a==a) {getline < file;u=$2-up;s=$3-sp;n=$4-np;i=$5-ip;printf ("%2.1f\n"),(u+s)/(u+s+n+i)*100;up=$2;sp=$3;np=$4;ip=$5;close(file);system("sleep 1")}}’
3. Download this code: cpuusage

Sources:

The pages below helped me alot:

http://listserv.ccjclearline.com/pipermail/kwlug-disc/2006-November/002132.html
http://b79.net/code/screenrc
http://www.mediacollege.com/cgi-bin/man/page.cgi?topic=screen

Songbird screenshot under Mac OS X

Songbird is coming to conquer the crown of this sort of audioplayers. The big download button on getsongbird.com, the domain, the site …. all that is familiar and is reminiscent of Firefox and Co.

Like back then with Firefox, it will take some time until Songbird reaches the masses. I tested it… and hey, I’m really impressed. This player just has the potential to reach the masses. The appearance just seems like iTunes, but there is more to discover under the hood.

Like with Firefox, Songbird can be extended - some interesting plugins have already been developed. There is mashTape that displays all sorts of useful information about the artist played (see screenshot), the Last.fm Album cover plugin, which shows covers from last.fm… or the album art manager, to manage covers locally.

There is even iPod support as plugin, which I have not yet tested. It is a very pleasant thing, to have a free (open source!) audio player as an alternative to Itunes and co.

Long live the birdy!

It’s not the first mac version, but there exists only an older ppc build.

Download: cdogs.dmg.

* Cdogs 0.4
* UniversalBinary
* needs OS X >= 10.4
* tested under Mac OS X 10.5, Intel.

I ported this nice little 2D-physics game to Mac OS X: http://numptyphysics.garage.maemo.org/

The SDL-Linux source was used to port and I only needed minor changes. Mail me if you want the project files. The port is native (Cocoa-SDL!), so no xorg server is needed

Download: here. (Latest version: 0.2 svn-11jan)

Requirements:

* Intel Mac. Sorry, no UB. Couldn’t make the library Box2D for ppc. If you tell me how much you would love it to have a ppc version, I may try it again.
* Mac Os X >= 10.4

Please comment for questions and tell me if it works for you. HAVE FUN!

Screenshot