Gaël Varoquaux - misc

Unison 2.48 binaries for ARM

2016-07-23T00:00:00+02:00

I have built static binaries of Unison 2.48 for ARM Run on my NAS, the arm architecture is necessary to synchronize with the recent Ubuntu.

unison-2.48.4-armel.zip

Warning

I will not support these binaries

I will not answer any questions or request on these binaries. I have built them for my personal use and put them online in case it might be useful for others.

Remark on backward compatibility

Why don’t the Unison devs ensure compatibility between minor version of Unison?

Breaking compatibility is bad practice, in particular between minor versions. It breaks the trust that users have in updating the software. Programmers complain that users always run old versions of OSs/libraries/programs, but this is explained by the fear of stuff breaking during upgrades.

Notes to build these binaries

I built this following instructions historically on http://www.crutzi.info/unison/binary/armel

I retrieved these instructions from the wayback machine, and adapted them to work on a more modern Debian system

To compile it, I used qemu and a Debian ARM image

1. Build a debian system under Qemu

Install the system (lasts a couple of hours, with some user input):

sudo apt install qemu-system-arm qemu-efi libguestfs-tools

wget -O installer-vmlinuz http://http.us.debian.org/debian/dists/jessie/main/installer-armhf/current/images/netboot/vmlinuz
wget -O installer-initrd.gz http://http.us.debian.org/debian/dists/jessie/main/installer-armhf/current/images/netboot/initrd.gz

# Create a drive
qemu-img create -f qcow2 hda.qcow2 5G

qemu-system-arm -M virt -m 1024 \
-kernel installer-vmlinuz \
-initrd installer-initrd.gz \
-drive if=none,file=hda.qcow2,format=qcow2,id=hd \
-device virtio-blk-device,drive=hd \
-netdev user,id=mynet \
-device virtio-net-device,netdev=mynet \
-nographic -no-reboot

Under Ubuntu:

sudo chmod 644 /boot/vmlinuz*

List the content on the /boot dir of the VM’s disk:

virt-ls -a hda.qcow2 /boot/

Copy the initrd and vmlinux:

virt-copy-out -a hda.qcow2 /boot/vmlinuz-3.16.0-6-armmp-lpae /boot/initrd.img-3.16.0-6-armmp-lpae .

Do symlinks:

ln -s initrd.img-3.16.0-6-armmp-lpae initrd.img
ln -s vmlinuz-3.16.0-6-armmp-lpae vmlinuz

The installed system is then booted with:

qemu-system-arm -M virt -m 1024 \
-kernel vmlinuz \
-initrd initrd.img \
-drive if=none,file=hda.qcow2,format=qcow2,id=hd \
-device virtio-blk-device,drive=hd \
-netdev user,id=mynet \
-device virtio-net-device,netdev=mynet \
-nographic -no-reboot -append "root=/dev/vda2"

2. Build unison under the debian system

Download the unison source package from

Then compile the files within the qemu ARM environment:

apt-get update
apt-get upgrade
apt-get build-dep unison
wget https://github.com/bcpierce00/unison/archive/v2.48.15v4.tar.gz
tar -xvzf v2.48.15v4.tar.gz
cd unison-2.48.15v4
make UISTYLE=text NATIVE=true STATIC=true

You might need to remove the ‘-unsafe-string’ option as detailed in https://github.com/bcpierce00/unison/issues/211

The binary will be in src/unison

New website

2014-10-09T00:00:00+02:00

I am moving my website to a new design, relying on Pelican and more modern CSS.

So far, I had been using rest2web to generate the static part of the website, and a local install of wordpress for the blog. I wasn’t doing good on keeping the wordpress install up to date, and I eventually got hacked. It was hurting my desire of simplicity to need a dynamic website. The combination of Pelican for my content, and Disqus suits very well my need, as it enables me to have a simpler website, and still have blog posts and discussions.

I also took the opportunity to clean up the website, remove some old content, and move my travel pictures to flickr.

Technical choices

Pelican for the core engine. I like the fact that it generates a static blog, that it uses restructured text to store the content, and jinja as a templating engine.

One interesting aspect of redoing my website with a more modern content managment system was that I could lay out the information based on tags and categories, rather than the old way of having a tree of nested topics. This is much more flexible because one article is likely to fall in many topics. Modern information organization is moving away from the notion of path used to access to an entry, to the notion of set of properties (tags here).
Pure CSS as a CSS base layer. I chose to use Pure CSS rather than Bootstrap as it is a pure CSS framework (no javascript) and it is much lighter. I find that Bootstrap websites can easily slow down browsing (due to download size and javascript). Bootstrap also does play very well with html documents in which ones doesn’t control the class tags, as those generated from restructured text. But that’s true of most web front-end frameworks. Another option was Foundation. I didn’t explore it in details, but it looked like an interesting tradeoff between Pure, which is very bare bones, and Bootstrap, the heavy lifter. I chose to go for the most lightweight option, because I had simple needs.

A result of using more modern CSS is that the website should look good on any screen size, from very large screens to mobile phones.

SVG Word map of countries

2010-08-24T10:55:00+02:00

To be able to visualize some quantities attached to countries all over the world, I needed a image with various countries color-coded. The fantastic matplotlib basemap package was not an option as I really needed a static image.

So I generated an SVG image with all the countries. It was generating by tracing a bitmap, so it has a lot of imperfections, but being an SVG with each (major) country as a different object, it can be used to create a colored-code world map. I am uploading it here under a public-domain license. Enjoy!

PNG

SVG: countries.svg

Frank Willison on the French

2009-01-29T17:20:00+01:00

I couldn’t help myself, this Franck-Willison quote is brilliant:

“And the Europeans accept chaos and know how to live with it. I came away from France believing in the strong faith of the French people, not because of their magnificent cathedrals, but because I saw them drive around L’Arc du Triomphe. As they careened around this monument in vehicles that were little more than motorized Altoid containers, they looked like a network run by Linux servers: little packets hurtling within inches of each other, traveling together for a time, separated by other packets coming from other sources, reassembling as they sped out of the circle and onto the Champs Élysées. It’s no surprise to me that much of the interest in IPv6 is coming from France–if they don’t understand delay-sensitive traffic in France, they understand it nowhere.”

GPS coordinates for the world’s major cities

2008-12-31T00:53:00+01:00

This may sound stupid, but I have failed to find on the web a simply-accessible text file giving the GPS coordinates for the world’s major cities. The web site World-gazetteer is helpful, but doesn’t really give what I want. So I wrote a small Python web-scraping script to get the data I needed. BeautifulSoup is really cool, but somehow I feel I could be spending my time in a better way. And on a side note, I still struggle to get good conversion from unicode to ascii (I needed ascii, as this will be fed to software that don’t understand unicode).

I am attaching both the data file produced, and the Python script, in case someone finds them useful.

Update: About 10 minutes after posting, I did a better google search, and found a page that might have been easier to scrape: http://www.bcca.org/misc/qiblih/latlong_oc.html

Hello world… hu I mean Planet !

2008-01-02T22:41:00+01:00

Thanks to Jarrod Millman, we now have planet.scipy . This means it is time for me to create a blog, on top of my good old static site.