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            <p>TL;DR: If you find that your B1160 jobs are being marked as 'held' in the printer status applet instead of being sent to the printer, you need to add your printer to CUPS after you have installed the Dell unified printer driver.</p>

            <p>&nbsp;</p>

            <p>I hardly print anything at all so when my ancient HP p1105 printer died (or the toner was used up not sure which), it was time to shop around for a new budget printer and the Dell B1160 was what I chose. This will probably last a few years too and by the time the cartridge is used up it will be cheaper to replace the whole printer rather than the toner, but first lets try to get at least the test-page printed cause what ever you do nothing get's sent to the printer.</p>

            <div style="text-align:center; margin:15px"><img alt="print job held" src="https://s3.amazonaws.com/images.raditha.com/blog/images/2014/dell.png"></div>

            <p>Dell has very kindly created a driver for this device instead of passing the buck to the open source community. The only trouble with the driver is that it's lookings for SANE libraries during the installation. I can see why you would need it for a multifunction printer but the B1160 doesn't have a built in scanner.</p>

            <div style="text-align:center; margin:15px"><img alt="SANE for a printer?" src="https://s3.amazonaws.com/images.raditha.com/blog/images/2014/dell-installer.png"></div>

            <p>So it turns out that using the dell unified driver installer is not sufficient you need to add the printer manually to CUPS as well. It so happens that cups may tell you that the &nbsp;printer has already been added but if you try to remove it you will be told that the printer does not exist! So use system-config-printer or the cups web interface ( <a href="http://localhost:631">http://localhost:631</a> ) and after that you will find that items are no longer being 'held'&nbsp;</p>


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Dell B1160 'Held'

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            <p>I had prevously made a couple of half hearted attempts to learn the R language without much progress. Then inspired by my own<a href="python-in-48-hours.html"> Python in 48&nbsp;hours</a> and Ruby in 24 hours efforts, I decided to go on a crash course in R today. My interest in R is mostly because we have a lot data at road.lk that I would like to look at through different eyes. I also have access to a lot of scrabble tournament data that need analysis. The latter can certainly be done most easily with python but to be a good it never does any harm to have a lot of different weapons in your Armoury. So it's 7:31 in the morning of August 7th. Lets start.</p>

            <p>&nbsp;</p>

            <p>The first stop was the <a href="https://class.coursera.org/rprog-006">Coursera R lang course</a>, but lecturers aren't my thing. So next stop was the <a href="https://www.datacamp.com/courses/introduction-to-r">Datacamp courses</a>&nbsp;but they seem to be too trivial. Can't blame them cause their target audience probably isn't hard core programmers but data scientists. Next stop was the <a href="https://www.r-project.org/">r-projects</a> documentation, but that's where I got lost in the maze. There were too many to choose from. So as at 5:49 am in the 9th of August, I haven't gone anywhere. The fact that I couldn't devote my full attention to R didn't help either. So this is going to need another effort next week.</p>


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R In 24 Hours

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            <p>Internet Scrabble Club is the cool place to play scrabble online. Some of the world's top players hang around at the ISC. Play online doesn't mean you can play with the browser, rather you need to download and install one of their clients. Fortunately they have clients available for Linux, Mac and Windows. The only trouble is that the linux client freezes at the slightest excuse. You can never seem to play more than one more before it either disconnects or stops responding at all. The obvious solution then is to try running it under wine.</p>

            <p>&nbsp;</p>

            <p style="text-align:center"><img alt="ISC on Linux WINE" src="https://s3.amazonaws.com/images.raditha.com/blog/images/2014/isc.png"></p>

            <p>&nbsp;</p>

            <p>The windows exe running under wine doesn't even get as far as that. It fails at the login screen. The dialog box to enter the username and password is permanently damaged and wants repainting but it never seems to happen. So it was time to look back at the java version of wordbuff and it wasn't long before I figured out that the problem was because Open JDK and wordbuff doesnt' see eye to eye. It runs easily with the Oracle JVM.</p>

            <p>&nbsp;</p>

            <p><code>export JAVA_HOME=/usr/local/java/jdk1.7.0_65/<br>
                    /usr/local/java/jdk1.7.0_65/bin/java -jar wordbiz.jar </code></p>

            <p>&nbsp;</p>

            <p>Ok a few footnotes:</p>

            <p>The client software is named wordbuff. Does that have anything to do with Derek McKenzie who runs the popular <a href="http://word-buff.com">word-buff.com</a> website?</p>

            <p>Wordbuff seems to save the username and password in a clear text file named Config</p>

            <p><a href="http://isc.ro">ISC</a> seems to save the password in clear text on their server (if you try the password reset, they send you your old password back in a plain text email)</p>

            <p>&nbsp;</p>


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ISC on Linux

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            <p>This blog now runs on Google App Engine with the&nbsp;NDB serving as the&nbsp;storage backend. In the process of writing the (python) code I ran into some complications regarding how it uses indexes. First we will consider a query on one of the wordpress tables in a mysql database.</p>

            <p>explain select * from wp_posts where post_type='post' and comment_count = 0;</p>

            <p>explain select * from wp_posts where comment_count = 0 and post_type='post';</p>

            <p>The comments_count column does not have an index so mysql query optimizer is smart enough to figure out that the 'type_status_date' index is the right one to use for both queries.&nbsp;</p>

            <p>&nbsp;</p>

            <div>
                <pre style="width: 100%; overflow-x:auto; word-wrap:normal; white-space: pre;">+----+-------------+----------+------+------------------+------------------+---------+-------+------+------------------------------------+
| id | select_type | table    | type | possible_keys    | key              | key_len | ref   | rows | Extra                              |
+----+-------------+----------+------+------------------+------------------+---------+-------+------+------------------------------------+
|  1 | SIMPLE      | wp_posts | ref  | type_status_date | type_status_date | 62      | const |  974 | Using index condition; Using where |
+----+-------------+----------+------+------------------+------------------+---------+-------+------+------------------------------------+
1 row in set (0.38 sec)</pre>
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            <p>&nbsp;</p>

            <p>Now what if you tried to do a similar&nbsp;query on NDB? You would need indexes on both columns to begin with and you would also find that NDB expect two different indexes for these queries.&nbsp;One would take the form Index(comment_count, post_type) while the other would be Index(post_type, comment_count). Welome to the world of noSQL where no one really cares too much about storage. But if you are a GAE user you should care because you are paying for it as well as the&nbsp;read and write operations to the data store. More indexes you have higher the write cost. Unless you plan your queries judiciously you will find that they soon baloon out of hand but you are limited to 200 indexes max!</p>


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NDB Queries

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            <p>Flipped the switch. Finally. Wordpress has been switched off, as I have threatened to do so many times before and in fact claimed to have done at least twice! But this time it's real. This blog post is being written with the aid of a home made blogging system running on Google App Engine (python). The data is stored in NDB and the editor is <a href="http://ckeditor.com/">CKeditor</a>, with&nbsp;&nbsp;the comments being powered by Disqus.</p>

            <p>So what about the previous claim for switching to jekyll. &nbsp;Well I did do so for the <a href="http://photos.raditha.com/">photoblog</a> and I did do all the hard work for this one as well, but then for no apparent reason the whole damn thing stopped working.&nbsp;</p>

            <p>I couldn't be bothered to find out what caused it, particularly since Ruby isn't in my repotoire. So I said the hell with it and stopped blogging for a few months and then suddenly decided to come up with this system. It's said that the path to <a href="http://djangoproject.org">Django</a> mastery lies through building your own blogging platform. Well I can well and truely say that I have done that now.</p>

            <p>The system hasn't been without a few teething problems. The feed link broke and resulted in a lot of being being sent a bunch of notifications about new posts even when there weren't any (very sorry about that). And there are still a few 404 errors scattered about here and there (these will be fixed soon).</p>


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