Walltop
WallTop computers... recycle an old laptop by removing all the extraneous parts such as the cdrom drive, floppy drive, (dead) battery and then hanging it on the wall.
Hardware
My first attempt is based on a Dell Inspiron 3700 C466GT.
- 466 MHz Celeron processor
- 256 MB PC100 SODIMM memory
- one PATA slot
- two broken PC card slots
- one USB port
Removed: case, 4200 RPM hard drive, dead battery
Added: a shadow box frame from Michaels, a power supply from OSUsed, a CF to 44pin PATA adapter, a 1GB CF card, and an ASUS 802.11g WiFi USB adapter
I had to modify the frame to add cooling slots.
This laptop will only boot when you touch its power on button. To make the button accessible I mounted the motherboard upside down (what used to be the top is towards the wall when it's hanging up. I drilled a hole in the back about 3/8" diameter. You can poke the button with a pencil eraser to boot it up. Yes.. its a pain.
More hardware
Micron TransPort XT Notebook Computers CPU: Intel Pentium III 750 ~ 850MHz
- Standard Memory: 64MB~256MB
- Maximum Memory: 512MB
Dell
Which distribution to use?
After much research and experimentation I settled on Debian Live!
This allows me to build an image on a big fancy Ubuntu desktop system (Raven) and test it in qemu.
Once the image is built I transfer it to a Compact Flash card, which will be plugged into an IDE adapter and replace the incredibly noisy stock 4200 rpm hard drive.
I am also now using Debian Live! to build Asterisk phone systems.
Some other options that I investigated:
- Debian
- Damn Small Linux
- Puppy Linux (which immediately panics on boot)
- Movix
- Ubuntu, building a custom Live CD
Debian Live! installation
Install the tools to build Debian Live! systems
apt-get install live-helper
Build an image.
lh_clean --binary lh_config -b usb-hdd -k 686 --bootstrap-flavour minimal\ --packages-lists "stripped" --binary-indices disabled\ --memtest "disabled"\ --packages "x-window-system-core fluxbox\ openssh-server vlc gnash portmap nfs-common\ autofs debconf-english"\ --bootappend-live "nolocales" --syslinux-timeout 50
I build on a 64 bit machine so I have to say -k 686 to get the 32 bit kernel
Add scripts to config/chroot_local-hooks
02-fix_inittab.sh - changes runlevel to 5 and adds the tty7 login line so I have only one login running instead of default 5
40-bash_profile.sh - append or create a .bash_profile script that will run a script from nfs and then do a 'startx'.
50-windowmanager.sh - configures fluxbox startup files
99-make-export.sh - make the directories needed for autofs
Add files to config/chroot_local-includes I add the autofs.* files that I use to mount nfs servers.
Doing customizations, do this (as root)
lh_clean --binary lh_config lh_bootstrap # Prepare for a chroot system so you can do hacks lh_chroot lh_chroot_hosts install lh_chroot_resolv install lh_chroot_proc install chroot chroot #do the hacks here, for example "apt-get install asterisk". exit # Now remove the changes make to do chroot lh_chroot_hosts remove lh_chroot_resolv remove lh_chroot_proc remove # I wonder what this does lh_binary # Build the image lh_build
Copy image to CF: dd if=binary.img of=${USBSTICK}
To test image, start in qemu or convert img file to a vmdk and use vmware
To use in walltop, transfer CF to laptop and boot it
Customization that I might want to do
other codecs??? emacs21-nox libcurl3 realplayer? firefox - use iceweasel, unless like me your laptop is puny, then forget it! flash - use gnash??
I need something to do a slide show of pictures, driven from command line. Image-magick supports this.
Starting X / fluxbox without a window manager http://www.debianadmin.com/how-to-auto-login-and-startx-without-a-display-manager-in-debian.html
The basic principles
To make (large) changes, you build a new, complete image from scratch. You copy the new image to CF, put it in the computer, and boot.
I add scripts to config/chroot_local-hooks. I keep backup copies of the scripts at the top level so that I can wipe the config/ directory and rebuild it from scratch. I keep copies of the files that will be included in MyConfigIncludes/
Create scripts to customize the images
nn-name.sh where 'nn' is a number to control execution order, and 'name' is a meaningful name, for example 01-password.sh would be used to install local user accounts and set user and root passwords.
WiFi Network
These are WiFi cards I was considering using. They are still in my junk box but when I actually went to plug one in, I found that this Dell's PC card slots are messed up, so instead I plugged in an ASUS USB adapter.
D-Link DW650M http://sourceforge.net/apps/mediawiki/ndiswrapper/index.php?title=D-Link_DWL-G650M
Microsoft MN-720
I have not completed testing of ndiswrapper since I switched to using the USB adapter. Here are my notes for the NEXT walltop. I have several more laptops...
To use these I need to use the manufacturer's drivers + ndiswrapper. http://wiki.debian.org/NdisWrapper
In chroot environment
m-a prepare m-a a-i ndiswrapper echo ndiswrapper >> /etc/modules
WiFi Security settings
With this device it's just a matter of plugging it in and then getting the correct security settings for the network. I was able to turn off security on my Linksys and get a connection. Since my ultimate goal is to take this to work and hang it on the wall there, turning security at the WAP off is not an option.
I first I spent a couple hours wrestling with getting it to work with wpa_supplicant on an Ubuntu desktop. I tried all sorts of combinations of security settings to no avail. Very frustrating.
Then I found "wicd". I installed it (apt-get install wicd), started the daemon (sudo wicd) and the client (wicd-client -n) and had a link up in about 60 seconds. Conclusion: USE WICD!!
Check the downloads page for more documentation http://wicd.sourceforge.net/
In Debian Lenny, wicd is a backport, so installing it requires additional work. Add this to /etc/apt/sources.list; like this
echo 'deb http://www.backports.org/debian lenny-backports main contrib non-free ' > config/chroot_sources/backports-wicd.chroot wget -O - http://backports.org/debian/archive.key -O config/chroot_sources/backports-wicd.binary.gpg
Then in the chroot environment I do this
apt-get update apt-get install debian-backports-keyring apt-get -t lenny-backports install wicd
...which installs about a zillion more dependent packages! All just to get my wireless link going! Oh well.
LSH
The lsh-server is a small SSH server.
By default it generates keys on the first run, which alas is every time on a Debian Live system. So I generate keys on the development host and copy them into the config tree.
This is how I generate the seed file and keys.
mkdir ~/.lsh && cd ~/.lsh lsh-make-seed --sloppy -o yarrow-seed-file lsh-keygen | lsh-writekey
Testing
To test the image in a virtual machine, you can either start it in qemu or convert the img file to a vmdk and use vmware.
Of course, you can also the virtual machine to boot from the USB stick but testing the img file first means you don't have to keep copying the image to the stick.)
"Qemu" is installed on 'dev' already. You need to set up an X11 connection back to your desktop to use it, if you are burdened with a Windows machine see the Cygwin page. When you have an xterm window open on your desktop, type 'qemu binary.img' and wonder at the marvels of modern technology.
Once the Qemu window captures your mouse you can escape with Ctl-Alt. Thought you might want to know that.
Testing image in Qemu
There are clever ways to set up Qemu networking. It requires setting up a TAP interface on the host. Not sure if I am up to that. I think this is the proper way to do it but I don't want to accidentally shut down my server right now.
Here is the command to start the image in qemu. This MAC number is one digit off from the real thing. (24 vs 25) (qemu networking hints)
qemu -net nic,model=rtl8139,vlan=1,macaddr=00:e0:29:93:3a:25 binary.img
Deployment
Copy the image to a CF card, completely overwriting it: dd if=binary.img of=<devicename>. You can get the device name with dmesg, it will be buried in the last few messages after you insert the stick. Something like /dev/sda. Don't use the first partition (which would be /dev/sda1), use the whole drive, you have to overwrite everything there including the boot block and the partition table.
Note: If you select the wrong device name you can make the host system unbootable in about 250 mS. If you do this, don't come whining to me about it. Fix it.
