Another update to Quizzer, now at version 3. But more importantly, updates to the Linux Sea related chapters are made available online – get a taste for it at the online quizzer set.
Feedback is, as always, very much appreciated.
Question yourself v2
A new version of the Quizzer webscript is available. The demo has also been updated with quick tests on the first few chapters of Linux Sea.
More exercises on the following chapters will follow soon.
Updates to the script include visual accept/reject of single-choice and multiple choice answers and improved support for Internet Explorer (which I don’t have at home to validate).
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Question yourself
Do you ever write down things in the hope you never forget them, but still think it would be better if you could somehow take a test of that subject from time to time to make sure you don’t forget?
I do, and I found it quite difficult to keep the knowledge live without having to reread the things every now and then. For that purpose, I started writing a simple JavaScript/XML/XSL fileset that allowed me to present questions (randomly if necessary) from a structured set of questions. In the beginning, it was too simple to share (string matching) but quickly grew to something more elaborate: regular expression support, multiple string-answer support, in-paragraph answer boxes and single/multiple choice answers.
With this fileset in place, I can keep track of things I would most likely otherwise forget: just select the category which I want to take a test from, and start with a (lot of) random question(s).
I’ve decided to put this fileset online (including demo files) and will extend the demo file with questions regarding my book, Linux Sea, allowing readers of the book to take online tests after they’ve finished a chapter.
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SAI and N-O-SQL
Yesterday (argh, the day before yesterday) I went to a SAI conference on nosql. In Belgium, SAI is a non-profit organization for IT people which focuses on knowledge sharing.
The conference that day was on nosql. The presentation given by OuterThought was very good and offered a nice introduction to the “new types of database architectures” that are being actively developed as we speak.
Although the use of these nosql databases within KBC (where I work for) is limited (I’m not aware of any application that is already using this technology) it would be plain wrong to discard the technology as “too immature”. With the recent developments that we face in the IT industry, applications are nowadays quick in adopting such new technologies and I suspect that off-the-shelf applications will soon come with such nosql database technology as part of the solution.
For large enterprises, this does face some (hard?) challenges: how do you control your network usage (some of the technologies are easy to use, but hard to tune), how do you design your architecture, where is your data, how can you ensure that you do not “lock in” into a single nosql technology (i.e. how do you ensure interoperability and migrations between technologies), do you still need SAN-based replication or will you now let the technology handle this for you, etc.
So yes, the nosql technology is nice to look into (and definitely something to follow up on) but make sure you don’t introduce it in your organization without thinking about the entire integration and management aspect.
A dozen pages added
Just a quick heads-up that a dozen pages in the Linux Sea book have been added. Nothing spectacular, just a few more paragraphs on services/runlevels, a few updates on software management and on boot failure resolutions.
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License support in Gentoo
It’s a bit sad that Gentoo didn’t promote this more, but Gentoo users now have support for license-based masking.
What does this mean? Well, previously, Gentoo already supported various masking reasons (like stable versus staging – the x86 versus ~x86 saga, package.mask’ing – for security reasons or critical bugs, …). Now, a new feature is added: license masking.
By default, Portage accepts all non-EULA licenses. If a package uses a EULA license, you’ll get a failure message stating that the license is ‘masked’.
Now, what good does this do for users? Well, you can now ask Portage only to accept certain licenses (like @FSF-APPROVED, which is a list of all FSF-approved licenses) and deny the installation of others. Nice, isn’t it?
I’ve added information regarding package license states (and the global as well as per-package unmasking support through /etc/portage/package.license) to the Linux Sea document.
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Executing, but only when you’re home
Sometimes you want to execute a particular command, but only when you’re at home. Examples would be running fetchmail (or fetchnews) through cron, but you don’t want this to run when you’re in the train, connected to the Internet through GPRS…
My idea here would be to create a script (say “athome.sh”) which returns 0 if you’re at home, and 1 otherwise. The key of the script is that the MAC address of your (default) gateway is unique.
#!/bin/sh
GW=$(/sbin/ip route | awk '/default/ {print $3}');
MGW=$(/sbin/arp -e | grep ${GW} | awk '{print $3}');
if [ "${MGW}" = "00:11:22:33:44:55" ]
then
exit 0;
else
exit 1;
fi
With this script, you can then run athome.sh && fetchmail. If you aren’t home, athome.sh will return 1 and the fetchmail command will never be executed. When you are, the command returns 0 and fetchmail is launched.
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Switching to database architecture
It’s finally committed: I’m going to dive into the realms of database architecture. It’s with some sentiment that I’m leaving the expertise field of Apache, J(2)EE and WebSphere, but seeing the database architecture field makes it up well. I’m starting to get acquainted with Oracle DB as first platform and IBM DB2 + Microsoft SQL Server are pending. Exciting times are coming!
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Translations to “Linux Sea”
A few people have contacted me if they were allowed to translate the online book I’m writing (Linux Sea). Of course they are, the license allows it. However, I recommend to wait a bit. At this moment, I’m not going to release the docbook sources (I’m not writing it in DocBook, but I’m generating from another XML into DocBook) until I’m happy with the final result.
I’m glad to see that the document is well received. There is still lots of work on it (more excercises, a thorough spelling / grammar check, elaborate on certain topics, …) so stay tuned for further updates. Why are those updates “slow”? Well, let’s say that I use a “fair share scheduling” principle on all my hobbies ;-)
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Small updates on Linux Sea
A few updates have made it to the Linux Sea book:
- Information regarding ndiswrapper
- Some information about udev and the symlinks that it creates
The PDF version has been updated as well.
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