There is currently a petition on the Prime Minister’s website calling for a clear ban on software patents. I was hesitant to sign it, not because I want software patents, but due to the langauge of the petition.

Software patents are used by convicted monopolists to threaten customers who consider using rival software. As a result, patents stifle innovation.

Patents are supposed to increase the rate of innovation by publicising how inventions work. Reading a software patent gives no useful information for creating or improving software. All patents are writen in a sufficiently cryptic language to prevent them from being of any use. Once decoded, the patents turn out to be for something so obvious that programmers find them laughable.

It is not funny because the cost of defending against nuicance lawsuites is huge.

The UK patent office grants software patents against the letter and the spirit of the law. They do this by pretending that there is a difference between software and ‘computer implemented inventions’.

Some companies waste money on ‘defensive patents’. These have no value against pure litigation companies and do not counter threats made directly to customers.

The aggressive and ad-hominem language doesn’t do anything to help the cause. It looks unprofessional and will result in the authorities ignoring it as a fanatic incoherent rant and will put off people from signing the petition. I’d be interested to know how many people didn’t sign because of the text.

It’s been a while since I last wrote an article, but I’ve just published a new one on troubleshooting networking. It’s based on a couple of emails I sent to a mailing list helping someone with their networking problem. I decided to clean it up a bit and publish it. It is mostly for finding where the problem lies, rather than fixing the issue, but I would be grateful for any comments you have, particularly if you think I’ve missed any obvious steps.

mojo-jojo david% ant clean
Buildfile: build.xml

clean:
     [echo] Deleting all project files
   [delete] Deleting directory /home/david/tomcat5.5-5.5.20/servletapi
   [delete] Deleting directory /home/david/tomcat5.5-5.5.20/container
   [delete] Deleting directory /home/david/tomcat5.5-5.5.20/jasper
   [delete] Deleting directory /home/david/tomcat5.5-5.5.20/connectors
   [delete] Deleting directory /home/david/tomcat5.5-5.5.20/build

BUILD SUCCESSFUL
Total time: 46 seconds
mojo-jojo david% ls
build.xml  debian/
mojo-jojo david%

blink

I decided it was probably time that I started backing up my PostgreSQL databases and ended up writing a quick script to do just that. I did have a look at pg_dumpall, but it appears to only write to stdout, meaning I couldn’t have a file per database like I wanted.

#!/bin/bash

set -u
set -e

dumpdir=/var/backups/postgresql

date=$(date +"%Y-%m-%d")
mkdir -p $dumpdir
find $dumpdir -name "*.sql" -mtime +10 -exec rm {} ;
for database in $(su - postgres -c "psql -l -t" | cut -d'|' -f 1 | grep -v template0);
do
        su - postgres -c "pg_dump $database" > $dumpdir/$database-$date.sql;
done

su - postgres -c "pg_dumpall -g" > $dumpdir/global-$date.sql

Just stick that in /etc/cron.daily/postgresql-backups and you should end up with 10 days worth of backups. I’m not sure if postgreSQL can have spaces in database names. I’m assuming it can’t. The only other issue to deal with is not storing it on the same machine as the database server, let alone on the same physical hardware or even worse, the same partition.

Update: Corrected typo and added dumping global objects to the script.

Sorry to anyone that got spammed by my change to pyblosxom earlier today. I changed the base url, which changed the link of the entries. I should sort out having proper guids.

It can be quite discouraging to type “yum update” and have yum simply go off forever. Among other things, one must wait a great long time to distinguish this behavior from yum’s normal mode of operation. Other times, it comes back very quickly with a message saying, for all practical purposes, “RPM crashed, you lose, sorry.”

via LWN.net (subscription required)

Jonathan Corbet normally manages to amuse me on a weekly basis, but this time he’s outdone himself. Consider my LWN.net subcription renewed for another year.

Update: I;ve been convinced to include a subscriber link to the article for those without LWN.net subscriptions. http://lwn.net/SubscriberLink/210373/8badbe4f9c463fb8/

Andreas, use atom rather than RSS. It has a <updated/> element for the last time the entry was updated and a <published/> element for the date the entry was published.

If you want to stick with RSS, you can use the <dcterms:issued/> element for the initial published date and one of <pubdate/>, <dc:date/> or <dcterms:modified/>. Don’t forget to include the xml namespace for dc and dcterms.

Erich, I’m not entirely sure what you did to break Planet, but using a strict feed parser will just result in you missing a significant number of entries. People sadly don’t produce valid feeds and will blame your software rather than their feeds. It doesn’t help that a number of validators aren’t entirely strict and that RSS doesn’t have a very comprehensive spec. RSS is a lot worse than Atom, in part thanks to the Atom validator and very well thought out spec. It’s for this reason that I ended up writing Eddie rather than using ROME as it was a DOM parser and just failed to get any information out of a non-wellformed feed. Eddie on the other hand is a SAX-based parser. In a recent comparison, an Eddie based aggregator managed to correctly parse several more entries than a ROME based aggregator one particular day.

You also have major aggregators being liberal. Sam Ruby discussed this recently with Bloglines becoming the defacto validator; if bloglines parses it, then it’s valid. We had the same problem with HTML with people making sure their pages worked in a browser rather than met the spec.

I suspect the problem you had with Planet is that you failed to close a tag, causing the rest of the page to be in bold or be a link etc. This is fairly easily solvable and in fact has been with FeedParser, which is the feed parsing library Planet uses. It has support for using HTMLTidy and similar libraries for fixing unbalanced elements. Eddie uses TagSoup to do a similar thing. As a result I’ve not noticed any particular entry leaking markup and breaking the page. Parhaps Planet Debian just needs to install one of the markup cleaning libraries.

I agree that people should use XML tools where possible. Unfortunately, most blogging tools use text based templating systems, which makes producing non-wellformed XML too easy. To deal with this I pass all my output through an XSLT filter, which means that everything is either well formed or doesn’t output at all. Unfortunately I don’t think everyone would be capable or willing to use XSLT.

I’ve just installed a bunch of RPM packages that were built on CentOS and targetting Redhat-like linux distributions onto a Solaris server. Even scarier, it worked.

I feel dirty.

I was using our Fedora 3 server and decided to restart sshd running in a chroot:

[root@winky /]# /etc/init.d/sshd restart
Stopping sshd:/etc/init.d/sshd: line 212: kill: (1483) - No such process
Connection to winky closed by remote host.
Connection to winky closed.
mimsy david% ssh winky -l root
ssh: connect to host winky port 22: Connection refused

Thank you very much Fedora.

A “friend” of mine has recently been sending me forwarded jokes and other assorted crap we all grew out of sending about 5 minutes after we learnt how to send emails. This I can cope with, but recently, for every email she sends, I’ve been receiving an automated email from a server somewhere telling me that it’s blocked an attachment, once for each attachment in the original email. That’s crime number one. Looking at it further it appears that its not the sender’s mail servers doing it, but once of the recipient’s mail servers. When it gets an email with an attachment it’s blocked, it emails everyone in the To: header to tell them, irrespective of whether they are local users or not. That’s crime number two.

I thought I’d email postmaster@capita.co.uk to tell them of this problem, but unsurprisingly it bounced. That’s crime number three. Looking on their website, I couldn’t find any technical contacts, which wasn’t really surprising. I did how ever find a “general enquiries” form, so I filled that in. Unfortunately, they used the following html for the message box:

<textarea name="Feedback1:fldEnquiry" rows="6" cols="1"
   id="Feedback1_fldEnquiry" class="enquiryTable"></textarea>

The result is that you get a text box 6 rows high and one column across, which is basically unuseable. Interestingly they appear to add style=“width: 350px;” in IE, which makes it work. I’ll make that crimes 4 and 5, cos doing different things for different browsers is a crime in itself.

I await a phone call or email from them.