Thursday, 27 May 2010

Not-so-lucid Lynx?: Ubuntu 10.04 not ready for ADMIRAL

We recently tried to update our ADMIRAL system configuration to use Ubuntu 10.04 (Lucid Lynx) rather than 9.10 (Karmic Koala). It has been our plan to base ADMIRAL on a version of Ubuntu designated for Long Term Support (LTS), and 10.04 is the most recent such system.

Unfortunately, we have run into a number of problems that mean we shall stick with 9.10, which has been performing very well, for the time being.  At the heart of these problems is the vmbuilder package we use to generate ADMIRAL system images.

Ongoing notes about the problems encountered can be seen here

Friday, 7 May 2010

mod_dav, do we have a problem?

Tracking down a strange bug this morning, using Javascript code in FireFox+FireBug against Apache 2.2 and mod_dav. My test code does a PUT soon followed by a HEAD to the same URI (part of logic that tests to see if the file just created actually exists). But the HEAD command returns inconsistent results: sometimes 404, sometimes not, running the same test suite with no other changes. I did manage to see the incorrect sequence in a Wireshark trace, so I think that lets FF off the hook here.

A simple, but dubious, workaround is to put a 100ms delay in the test suite after initially creating the test fixture data; now all tests run fine, repeatedly.

I still find that FireFox can be a bit inconsistent in the time it takes to do things (garbage collection?), so some tests time out occasionally, but I can live with this.

Using: MacOS 10.5 and 10.6, Apache 2.2 (XAMPP distribution), Firefox 3.5.7, jQuery 1.4.2