Last night, I finally got my temperature sensors going, including a nice and shiny munin plugin giving me pretty graphs. So far, I only have a sensor in the loft, but I’ll spend some days putting sensors in the rest of the house as well.

Robert McQueen asked me on twitter how this all was set up, so I figured I’d blog about it. The sensors I’m using are the DS18B20 ones from Dallas Semiconductor. You can probably buy them from your local electronics supplier, but mine charges around 75 NOK a piece, so I just bought some off Ebay. It takes a bit longer, but I paid about 1/10th the price.

For logging, I’m using my NAS, which is just a machine running Debian, an USB to serial adapter and an serial-to-1-wire adapter. Thanks a lot to Martin Bergek for the writeup and the ELFA part numbers for diodes.

Since I’m lazy, I ended up just writing a plugin for munin. It uses owfs, which I downloaded from mentors.debian.net. I also offered sponsorship for it, assuming a few small issues are cleaned up, so hopefully you can install using just Debian in the near future.

owfs is fairly easy to work with, and the plugin uses the aliased names if you provide aliases, so you can know what the temperature in a given location is, rather than having to remember 64 bit serial numbers.

I recently got my hands on a Kenwood AT641, a fruit juicer attachment for the Chef/Major series of kitchen machines, and now I’ve had the pleasure of actually using it.

The AT641 is a high-speed, rotational juicer which works by the principle of making a puree of the apples (or whatever else you’re juicing), using a spinning plate with sharp studs on it, and then accelerating the puree against a cone-shaped piece of metal with small slots in it, working somewhat like a sieve. The juice drips down and is collected into a jug, the meaty bits of the apple is sent up and out into a small container for the bits that are thrown away.

It works reasonably well, the apple chute is quite large, so only large apples need to be cut in two, and none of the apples in the bucket I was testing with needed to be cut in more than two, and the apple juice I got out was nice and smooth, yet had some apply bits in it. It’s not clear, but that’s the way I prefer it, you can filter it later if you prefer clear juices. The build quality seems quite good with sturdy metal parts and thick plastics. It’s easy to dismantle once you’ve done it once, as there’s a trick to remove some of the parts.

On the downside, I had problems with it not managing to throw all the residual bits into the garbage container. They stuck to the to plastic above the metal cone and ended up clogging. This might be due to using the wrong kind of apples or something odd like that, but it was nevertheless a bit disappointing. I hope it will work better on my next batch. Cleaning the juicer requires dismantling it completely (which is done without any tools), and is fairly easy, except for some crooks that are hard to clean properly, especially given you can’t inspect them visually.

The whole process was fairly painless, including gathering an overfull bucket of apples, I spent an hour and a half making almost four litres of delicious apple juice.

All in all, I’m reasonably happy with the buy and hope my clogging problems are just a fluke.

Ben Nevis is the tallest mountain on the British Isles and also the name of one of the beers that the Bridge of Allan brewery makes. We visited the brewery around the start of the year. One of the beers we brought back was a Ben Nevis, described as a ruby red IPA. I’d classify it as more of a dark amber or brown ale. The taste is quite hoppy without being too bitter and with a fair amount of malt. A bit of fizz for a British beer, but I quite like it that way. All in all, a good and drinkable brown ale.

GNOME’s current sysadmin team is entirely volunteer-based, but as they are having problems finding enough (trusted) volunteers they are looking at hiring a part-time sysadmin. From looking at the GNOME wiki, it looks like they have had a meeting about the shortage of sysadmins. Citing from the minutes

The biggest problem that we’ve always had with the maintaining an active sysadmin team is the need for trust. If somebody shows up and wants to help out with a GNOME coding project, then it’s easy to build up trust over time. Suggest a project, have the person send patches, review the patches, if the patches are good, eventually give them direct commit access. However, for sysadmin work, we get a lot of people who want to help out, but it’s very hard for someone to contribute without being given a “dangerous” level of access to the GNOME systems.

Without having looked very hard, I would guess at the GNOME infrastructure being about as open as most proprietary software projects. There’s no way for me, as a third party to take a look at their infrastructure, take a look at their ticket backlog and submit patches for problems. Similarly, their nagios setup is behind a password prompt, so there’s no way for me to look at what services often have performance problems, suggest new monitors or point out any servers or services that are not monitored.

I’m not saying this to pick on GNOME, and as I’ll touch on below, they do seem to mostly do the right thing, and as one of the Freedesktop.org sysadmins, I know we’re not any better at least not yet.

One way to make it at least somewhat easier to contribute and get involved is to use a tool like Chef or Puppet and publishing the recipes. This won’t magically make everything transparent, but it’ll be a big step up. Ideally, the recipes should be complete enough that you can bootstrap a working system from them and so easier reproduce the infrastructure and any problems. It seems like GNOME is using puppet, but I couldn’t find the recipes.

Moving a complete infrastructure from something managed by hand to something managed using automation tools is a fairly big and involved process. However, if you’re serious about getting more people involved in your sysadmin team, I think it’s one of the more reasonable ways to opening up. It also means that when one of your servers is stolen, catches fire or suffers other catastrophic failure you can rebuild the service much quicker.

My last point is to open up your ticket tracker. Most tickets aren’t security sensitive, so provide a way for people to mark those tickets that are sensitive as such and make the rest public. The GNOME wiki makes this a bit confusing as it talks a bit about RT, but it seems like they actually use bugzilla for sysadmin tickets and just hide security-sensitive ones.

Russell Coker recently reviewed the Yubikey. The article mentions me, so I figured I’d correct a minor thing and respond to one of the comments.

First, the yubikey-server-c is my reimplementation of the Yubikey authentication protocol. Yubico provides two implementations, one in PHP and one in Java, neither which I’m particuarly interesting on building my system security on. Any bugs, misfeatures, etc in the C implementation are mine and mine alone.

Barak A. Pearlmutter, one of the commenters on Russell’s blog writes:

i don’t understand. isn’t this thing vulnerable to eavesdropping and replaying? even if it has a counter which changes etc, the things it is talking to (web sites) can’t know that some generated string is being reused. and it doesn’t even have a clock, so these things can be old.

The way the Yubikey works is you have a central authentication server. This has a secret shared with the key. Setting this secret is the primary function of the personalisation tool. When you press the button, the key takes its internal state (various counters, uid field, etc) and encrypts this using AES-128. This is then sent to the application you are trying to access, be it Wordpress, SSH or something else. Said application then contacts the authentication server which decrypts the ticket, checks the values of the counters to make sure it’s not a replay and responds with OK, bad ticket, replay and various other status codes. Based on this, the application grants or denies access.

There are really two places you could attack this: in the communication between the web browser and application or between application and authentication server. Both of those can be secured using SSL.

There is no way to use a single yubikey in multiple authentication realms without extra software. To do this, you would have a OpenID provider that uses the Yubikey for authentication, or you could have a Kerberos server with cross-realm trust.

As for the PAM modules and other tools so far not being packaged, yes, I know, I might fix it, but the current setup has the bits I use, as I use RADIUS authentication to get services to support both Yubikey and passwords.

I recently upgraded kemper.freedesktop.org to lenny. Collabora are nice enough to sponsor some of my sysadmin work for freedesktop and so making sure we are actually running a supported distribution was a good start. The actual dist-upgrade went fine, but when I rebooted with a 2.6.26 kernel, it just hung in the early boot phase. Luckily, a newer kernel worked fine. However, a newer kernel also breaks the NFS kernel server in Lenny. A short backport later, NFS was working fine, except annarchy (which NFS mounts from kemper) didn’t have nfs-common installed at all, meaning it lacked mount.nfs. Ooops.

Now, bugs was broken. It used an SSH tunnel from annarchy to kemper, but the startup script was nowhere to be found. I replaced it with a trivial stunnel setup which has the added advantage of reconnecting if the tunnel goes down.

The ssh config had to be fixed slightly. We used to use an old and patched sshd that stored all the keys in a single file. I added a tiny script to split that again. We also had MkHomeDir in sshd’s config, now replaced with pam_mkhomedir.

Another interesting thing I learnt is that the iLO ssh daemon chucks you out if you try to send enviromental options to it. Like, LANG which is sent by default. Slightly confusing, but easy enough to fix once I knew what the problem was.

In addition to kemper, I upgraded, but did not reboot fruit (the admin and LDAP host), due to not having the iLO password. I did not want to risk sitting there with a non-booting machine I could not fix. It’s going to be rebooted at some later stage. I also did not have the iLO password for gabe, which runs mail and some other faff, so I’ll have to schedule some more downtime in the near future.

Lucas asks about how free the N900 is, whether he can download and recompile and reflash. I’ll try to answer some of those questions.

No, you can’t download all the source. Part of it is just not open. I am not privy to Nokia’s decisions on why or why not to open up, but it seems like the user interface bits are only partially open. Hildon itself is open so you can poke at widgets and see how those work. The address book is not open. The telepathy component that talks to the cellular modem is not open.

As for having to accept EULAs, I honestly don’t remember accepting one of those, but I’m not going to say there are none. There’s at least one which is every time you install a package where you have to check a box saying “Yes, I know this package is third party and will not sue Nokia if it causes my house to burn down, my wife to divorce me or causes somebody to steal the car”. It’s annoying, but I’m willing to live with it.

The contents of apt’s sources.list is:

deb https://downloads.maemo.nokia.com/fremantle/ssu/apps/ ./ 
deb https://downloads.maemo.nokia.com/fremantle/ssu/mr0 ./ 
deb https://downloads.maemo.nokia.com/fremantle/ovi/ ./ 
deb http://repository.maemo.org/extras/ fremantle free non-free
deb http://repository.maemo.org/extras-devel/ fremantle free non-free

(technically, it comes from /etc/apt/sources.list.d/hildon-application-manager.list, not sources.list.)

I believe the built-in applications are generally not free, so rebuilding everything that is free will for instance leave you without any address book UI, the built-in map application or camera. Sadly, the X driver is also proprietary, so you won’t be able to see anything either.

I don’t think you can usefully install another free distro on the N900. You might be able to, at some point, assuming somebody goes to the effort.

The last question is “- Besides the non-free telephony stack, are there any other “antifeatures” I should be aware of?”. The telephony stack is implemented around Telepathy, which is LGPL-ed free software. While it’s correct that telepathy-ring (which talks to the cellular modem), the call UI and most of the address book are proprietary, the rest of Telepathy is free. There are SIP and XMPP connection managers that are free, and you can install more connection managers for MSN, IRC and so on.

Also, I think it’s important to emphasise that the telephony stack does not contain any antifeatures. The closest thing you would be able to find is probably the restriction to one active and one held call at the same time, but as one of the developers said: “That’s to prevent the UI from going mad”.

While I like to tout the N900 as a free phone, it is in no way completely free. Large parts of it are free, and almost as importantly: most of the programming interfaces are free and at least somewhat documented, so if somebody wants to replace the built-in camera application with a free one, they can replace the DBus interface that the camera app provides. Ditto for maps applications, the address book and so on.

I’ve been using an iphone since late 2007 as my primary phone and so I’ve gotten quite a few contacts and SMS conversations stored on it. Now that Collabora has given me a nice and shiny N900, I wanted to move my contacts and conversations over, but this proved to be a bit more work than expected. Please note that the following procedure worked for me, I have tried to take reasonable steps to prevent anything breaking, but if something breaks, you get to keep both pieces. I am not responsible and this comes with absolutely no warranty. Take backups.

What you need

• the addressbook and SMS SQLite databases. On my phone, they live in /var/mobile/Library/AddressBook and /var/mobile/Library/SMS.

• A copy of my iphone-contacts-convert script. It’s written in Perl and should be reasonably easy to understand. Put it in the same directory as AddressBook.sqlitedb.

• A copy of my iphone-export-sms script. It’s also written in Perl and should also be reasonably easy to understand. Put it in the same directory as sms.db.

• The smstools program you can get from this thread on talk.maemo.org.

The address book conversion script takes the SQLite database structure and converts that into a VCF file. It should be completely safe to run multiple times (it only does SELECT from the different tables in the contacts database, and you have made backups, haven’t you?).

If it dies with an “Unknown property”, “Unknown label” or other error, you can poke it and see if you can work out what’s wrong or drop me an email and I’ll see if I can help you. Assuming it doesn’t fall over, it will spit out a series of VCards, which you should store in a file, which you then to the N900 and open in the address book. Assuming you have less than 1000 contacts, they should now all be in your address book. If you have more, you need to split the file.

A couple of known limitations:

• It doesn’t handle some of the attributes, like job title, notes, department, display names, prefix and suffix. None of my contacts used those, so I just didn’t care. Patches to change this accepted. Also, it doesn’t handle custom attributes and birthdays. I intended to handle birthdays, but forgot and I have few enough contacts with birthdays that I just did it by hand.

• When it hits something it doesn’t know how to handle, it stops and you need to add the relevant handle to the code. I think it is mostly clear, how to, but again, feel free to contact me with any problems.

• Only tested on firmware version 2.2. Yes, ancient, but it’s what my iphone is running.

• If you have contacts that are organisations, they will come up with a blank full name. Just edit them on the N900 (pressing edit and then save immediately works fine) and they’ll be automatically fixed.

• No picture support. This looked a bit involved, so I didn’t do this bit. Should be possible with a bit of effort.

The procedure for exporting and importing SMS-es is a bit more involved. First, export the sms-es by running the perl script. It spits out a tab-separated file which you should copy to the N900 along with the smsimporter program from the smstools thread. Run ./smsimporter foo.csv and you should get all your SMS-es put into the conversation app. I ended up compiling my own smsimporter based on the 0.2.1 from the thread with the UUID patch too. Read the whole thread and it should be fairly clear.

Collabora was kind enough to buy N900s for all its employees. Yay! I got mine on Friday and has been playing around with it quite a bit. It’s very shiny and the user experience is a lot better than the N810. There are a few graphical glitches, it seems it’s XDamage damaging a bit of a window and it’s just not quick enough to repaint. Not a problem, and it has far fewer instances of just hanging for half a second which my iPhone has. That is, it hasn’t had any of those yet.

The screen is good, but resistive. Takes a short while to get used to when you’re used to capacative, but it’s not a problem at all. The keyboard is good, but I need to map something as the compose key. Having US/UK key caps and using the Norwegian layout is a bit confusing. Not really the fault of the device though.

The web browser is generally quite good. The gestures take a bit of time to get used to, but they’re not hard as such. Some of the default “applications” are implemented as just links to the web pages of services like Twitter, which is a bit silly as you don’t even get a version that’s optimised for the N900. They’re not useless, but they are absolutely nowhere near a real application. Also, the “Store” (Ovi Store) application/web page says “coming soon”, which is quite odd.

I’m not sure if I can change the selection of applications on the default application list, but modifying the desktop is easy. There seems to be few themes and background images available so far, at least in anything resembling official repositories. Hopefully this will improve over time.

So far, I haven’t actually written any code for the N900. I have some applications I want to write, mostly widget-style apps like “when does the next bus home leave from a bus stop close to me and where is the bus stop”, but also some other ones.

Battery life is not great. It almost did 48 hours today with a bit of use underway, and I did charge it before it ran completely out, but when I’m used to closer to a week, it’s not that good. Camera seems good and is quite fast, I think it took less than five seconds from opening the camera shutter until I had taken a picture. Shutter delay is quite bad at about a third or half a second, but this is a mobile phone (or mobile computer, as Nokia likes to call it) and not a DSLR, so I’m quite happy with it.

As a phone, it seems fine so far. I can make calls and accept calls and there’s no noticeable problems with it. It also functions as a modem/DUN over bluetooth, which is quite useful.

Build quality seems good, there’s a good feeling when sliding the keyboard in and out, but only time will tell how good it actually is.

So far, I’m happy with it, it’s a big step up from my previous UK phone (which is a Nokia E70; my iPhone is a 2G phone so I can’t use it here with the provider I’m using). Hopefully I’ll post more happy stories about it in the days to come.

In my last post about the ekey, I complained about two things: memory leak in the server and missing reconnects if the client was disconnected for any reason. I’ve meaning to blog about the follow up for while, but haven’t had the time before now.

Quite quickly after my blog post, Simtec engineers got in touch on IRC and we worked together to find out what the memory leak problem was. They also put in the reconnect support I asked for. All this in less than a week, for a device which only cost £36.

To make things even better, they picked up some other small bug fixes/requests from me, such as making ekeyd-egd-linux just Suggest ekeyd and the latest release (1.1.1) seems to have fixed some more problems.

All in all, I’m very happy about it. To make things even better, Ian Molton (of Collabora) has been busy fixing up virtio_rng in the kernel and adding EGD support (including reconnection support) to qemu and thereby KVM. Hopefully all this hits the next stable releases and I can retire my egd-over-stunnel hack.