Which PM Said “The last programme I wrote was a Sudoku solver in C++”?

Posted on May 4, 2015 by curiouscat

The last programme I wrote was a Sudoku solver in C++ several years ago, so I’m out of date. My children are in IT, two of them – both graduated from MIT. One of them browsed a book and said, “Here, read this”. It said “Haskell – learn you a Haskell for great good”, and one day that will be my retirement reading.

This quote was by Prime Minister Lee Hsien Loong of Singapore in April 2015. I must say I think the Western governments could be more effective with more scientists, engineers and coders in positions of power

His father was the first and long time Prime Minister of Singapore – Lee Kuan Yew

Another quote from the speech

40 years ago, after doing a math degree, I went on to study computer science, on my father’s advice. He said there is a future in that, and he was right. So for the Smart Nation Programme Office, I have put Minister Vivian Balakrishnan in charge, reporting to me. Vivian is both a hacker and a dabbler – He used to be an eye surgeon but since he does not get to operate on eyes nowadays, he dabbles in building simple robots, assembling watches, wireless devices and programming apps. His day job is to be the Minister for the Environment and Water Resources, and so when he builds apps, he uses the real time APIs generated by the Ministry.

It is useful to have governments around the world with different priorities. While the USA has turned against science and engineering in many ways others can pick up the slack. The USA had for decades been firmly in the position of promoting science and engineering. And the results of that are still blessing the USA with economic benefits including the wonderful results of silicon valley and far flung software development throughout the country.

photo of the Marina Bay Sands resort that resembles 3 sky-scapers connected on top by a large ship

The Marina Bay Sands casino and resort hotel has 3 towers connected on top by a what looks like a large ship. Singapore has a huge, and economically important port.

Singapore can improve but they sure do many things well. And the sense to continue supporting science, engineering and emerging technology will benefit them economically as we move into a world where those fields only grow in importance.

Prime Minister Lee Hsien Loong made the source code, the exe file, and a sample printout available after asked being asked about it online.

Hacking Saved Apollo 13

Posted on April 20, 2015 by curiouscat

Apollo 13 is a great movie on hacking. Hacking is applying intelligence to systems (including computer systems) to achieve a goal.

That can be done by criminals or devious people but it doesn’t have to be. It is a bit annoying that some people equating hacking only with criminal behavior.

The hacking culture is much more about figuring out ways to make technology work for people than about criminals. We shouldn’t let a small sub-set of hackers defile the term.

The Apollo 13 command module in which the astronauts splashed down into the Pacific Ocean. by HrAtsuo, via Wikimedia Commons.

When the oxygen tank exploded, Commander Jim Lovell made the famous statement: “Houston, we’ve had a problem.” The engineers on the ground and astronauts had to devise solutions to several very difficult problems and execute them quickly in order to return the damaged spacecraft to earth.

The amazing hacking done by the engineers (including the astronauts) at NASA to create a solution to the serious problems faced by Apollo 13 allowed the astronauts to return home safely. Without the amazing hacking done by those government employees the astronauts would have died.

It is also good to remind people, government workers do amazing things. Sure government workers can also harm society with bad work or by implementing bad policy. But it isn’t the fact that they work for the government that defines the value of the work they do.

Chrome Remote Desktop

Posted on January 13, 2015 by curiouscat

I am more often frustrated by Google the last few years that pleased with them. But they do still provide some pretty awesome tools. For example, Chrome Remote Desktop lets you access a computer over the internet (and lets you to allow another user to access your computer securely over the internet).

Chrome Remote Desktop allows users to remotely access another computer through Chrome browser or a Chromebook. Computers can be made available on an short-term basis for scenarios such as ad hoc remote support, or on a more long-term basis for remote access to your applications and files.

screen shot of chrome remote desktop

Chrome Remote Desktop is fully cross-platform. Provide remote assistance to Windows, Mac and Linux users, or access your Windows (XP and above) and Mac (OS X 10.6 and above) desktops at any time, all from the Chrome browser on virtually any device, including Chromebooks (including Android phones and iPhones). The iPhone app is new.

Some users worry about installing such an app given all the spying and hacking scandals. That is not a completely crazy worry. Google, and others, have been taking advantage of weak user control (and even bugs and work arounds to avoid stated user preferences) to track users and use that information to make money selling ads. With many cool and useful tools there are risk of them being misused. And practices of governments and huge corporations have been so egregious to give a sensible person pause. Still in the right situations this is a pretty cool looking tool (similar things exist but the combination of price [this being free] and simplicity make this interesting).

Compare WordPress Files on Server to Proper WordPress Version

Posted on November 18, 2014 by curiouscat

Sadly one of the hassles in managing your own WordPress blog is dealing with people that use your blog to serve spam content. These hacks can insert spam links into your pages and posts or create spam directories that are completely their own content on your domain.

There are many issues to deal with in re-establishing control of your server; but that isn’t the scope of this post.

This is just a tips if you are troubleshooting to try and determine what is going on. Often your server has been hacked to allow uploaded php pages to be added or for WordPress php files to be edited.

One way to track down if the files have been changed or new ones added is to compare the WordPress files on your server to the current files for a fresh WordPress install. This assumes your blog is using the current version, which hopefully it is because on the big improvement WordPress made is to make those updates automatic. That greatly reduces the chance to have WordPress be the vector to infecting your server. If you were using a older version then just compare to the field for that version from the WordPress server.

If you don’t have a current backup I would make a backup before I tried this. Obviously, don’t make any deletions or changes to your server unless you understand what you are doing. You can create big problems for yourself.

You can use the diff command to view the difference between WordPress on your sever and the fresh install from WordPress. I install the new WordPress in a new directory outside public_html. At the cli on a Ubuntu/Linux server:

[code]sudo wget http://wordpress.org/wordpress-4.0.zip
unzip wordpress-4.0.zip
diff -rq wordpress ../public_html/[/code]

wordpress-4.0.zip – replace with whatever the version is you are using.
../public_html/blog/ – replace with the path to your blog

Continue reading →

VPS, Cloud and Server Colocation Options

Posted on October 23, 2014 by curiouscat

Finding the right place to host your content is important. Thankfully their are several excellent providers. For virtual private servers (one server shared with multiple virtual servers) Linode and DigitalOcean. And there are lots of good choices but those two are widely appreciated for excellent service at a good price.

AWS ec2 (the Amazon elastic cloud) is not great for minimal hosting in my opinion – it adds extra complexity and is likely more expensive. But it is a great solution when you have the resources to manage it and you have significantly variable demand. Because of the ability to add capacity on the fly as you need it you can maintain a low baseline and add capacity only as needed and drop that extra capacity as soon as it isn’t needed.

Rackspace is another good option for hosting. Rackspace and AWS are often used for very large applications and sites but Linode and Digital Ocean also can serve those needs and provide similar options to add capacity on the fly.

All of these options require you to manage your server (which may well be a virtual server – that is just a portion of a actual physical server that you control).

Rackspace also offers co-location where your physical server is put in their network operation center with electricity; cooling; network and internet connections; and physical security managed by them and the server managed by you.

As colocation has evolved what is included and to what level things like physical security and redundancy are dealt with have evolved. It has become quite complex to understand all the options for those organizations that need more than a simple virtual private server. As often happens when their is a business need, people offer solutions. And there are companies that specialize in helping you find the best colocation options for your needs.

Today the cloud options have led many organizations to eliminate (or greatly reduce) there own network operations centers and colocation needs. But cloud options are not always the right choice. And for some needs cloud options are not appropriate yet (mainly due to security or legal issues stemming from security concerns).

Managing your own servers with a colocation arrangement can be significantly cheaper than cloud hosting options (especially if you don’t need to massively increase capacity to deal with short term bursts of demand). Of course, technology continues to change so quickly it is hard to predict what the future will bring.

Service quality is absolutely critical for colocation. While saving money is important, the reason colocation was selected (over virtual private servers or the cloud) is normally how critical the function was. Using experts to help sort through the options and assure the quality of service of provides is wise.

Zoom Level on Embedded umap OpenStreetMaps

Posted on October 13, 2014 by curiouscat

Curious Cat uses OpenStreetMaps and umap to create my own maps. Then I can embed them on my sites, for example here for Chiang Mai Thailand.

For some reason when you use umap and select the embed option it gives you code that leaves off the zooming altogether. It is an easy fix (and I imagine the code will be fixed making this simple advice obsolete). But for now this is all you need to do.

The url umap adjusts as you zoom the map in your browswer. For example, going to

http://umap.openstreetmap.fr/en/map/chiang-mai_18602

which the Curious Cat Chiang Mai map it will “redirect” to some really far out zoom level

Then you can zoom in a bunch to get the level you want to use to embed.

http://umap.openstreetmap.fr/en/map/chiang-mai_18602#14/18.7851/98.9907

The code created for you to paste into your page is

[code]<iframe width="100%" height="300px" frameBorder="0" src="http://umap.openstreetmap.fr/en/map/chiang-mai_18602?scaleControl=false&miniMap=false&scrollWheelZoom=false&zoomControl=true&allowEdit=false&moreControl=true&datalayersControl=true&onLoadPanel=undefined"></iframe><p><a href="http://umap.openstreetmap.fr/en/map/chiang-mai_18602">See full screen</a></p>[/code]

Which doesn’t include any zooming info so you get the super far our zoom default.

You need to add to the url

[code]src="http://umap.openstreetmap.fr/en/map/chiang-mai_18602[/code]

so that it includes the zooming info. So it would be

[code]src="http://umap.openstreetmap.fr/en/map/chiang-mai_18602#14/18.7851/98.9907[/code]

You can also see the link to “See full screen” isn’t using the zoom settings. If you wanted that link to a zoom setting of your choice you can set that also.

Note the view on your screen and the embedded map isn’t going to be identical. The map will likely cut off some of what you see (due to the sizing of the embedded map). You can also adjust the sizing of the embedded map by adjusting the height (they default to 300px, but you can make it 400px or whatever you want).

How to Dump SQL Result to a Text File Using cli

Posted on September 15, 2014 by curiouscat

Just a quick tip on how to dump a sql result to a txt file.

mysql -e “select * from [table]” -u[user] -p [database] > sqlresult.txt

For example:

[bash]mysql -e "select * from orders where product_id = 15" -uroot -p > sqlresult.txt[/bash]

Updates Needed When Upgrading from Apache 2.2 to 2.4

Posted on August 17, 2014 by curiouscat

I updated from Ubuntu 12.04 to Ubuntu 14.04 on a virtual private server.

When you do that update, Apache is updated from 2.2 to 2.4. Certain changes mean that until you update the site-available configuration files no web sites will work.

The quick checklist of what you have to do for each configuration

update the file to add or edit the directory details (where /var/www/curiouscatnetwork.com/public_html/ is the path to the website files on your server)
[bash]<Directory /var/www/curiouscatnetwork.com/public_html/>
Require all granted
</Directory>[/bash]
Remember if you have details needed for WordPress those instructions need to remain. I didn’t have a Directory area listed on my non-Wordpress sites.
The files now need a .conf extension so move the rename/move the files to the new name
[bash]sudo mv curiouscatnetwork.com curiouscatnetwork.com.conf[/bash]
Enable the new configuration
[bash]sudo a2ensite curiouscatnetwork.com.conf[/bash]
Reload apache to reload the new configuration
[bash]sudo service apache2 reload[/bash]

More details from Linode.

The upgrade to Ubuntu 14.04 LTS was interrupted (I quit a window using the wrong command – oops). Luckily it wasn’t a big deal. I was able to delete the lock file.

[bash]sudo rm /var/lib/dpkg/lock[/bash]

Then trying to update again

[bash]sudo apt-get dist-upgrade[/bash]

gave a message telling me what command to use to have the upgrade continue.

[bash]sudo dpkg –configure -a[/bash]

which seemed to work fine.

Reset Root Password on MySQL Database

Posted on August 15, 2014 by curiouscat

How to reset the root password on a MySQL database.

Stop mysql using this command:

[bash]sudo /etc/init.d/mysql stop[/bash]

Because you are not checking user privledges at this point, it’s safest to disable networking. Then, start the mysqld demon process using the –skip-grant-tables option using

[bash]sudo /usr/sbin/mysqld –skip-grant-tables –skip-networking &[/bash]

Next, start the mysql client process using this command:

[bash]mysql -u root[/bash]

from the mysql prompt execute this command to be able to change any password

[bash]FLUSH PRIVILEGES;[/bash]

Then reset/update your password

[bash]SET PASSWORD FOR root@’localhost’ = PASSWORD(‘password’);[/bash]

Fix for When a WordPress Blog Stops Displaying Images

Posted on July 26, 2014 by curiouscat

My WordPress network site stopped displaying uploaded images. I finally found something that works, though it is a lame “solution” in my opinion.

I found this advice and it worked for me. Insert the following in wp-includes/ms-files.php

adding ob_clean() before the readfile in ms-files.php

So you end up with:

[bash]// If we made it this far, just serve the file
ob_clean();
readfile( $file );
?>[/bash]

Caching seemed to make the images “disappear” slowly (they didn’t all go at once and using different browsers they “disappeared” at different times). So when I fixed it they “reappeared” at different times (it seemed like cached ones stayed disappeared for awhile).

The advice mentions the image files being seen as “corrupted.” The files seem unlikely to actually be “corrupt” because these are images that worked for years and then all of a sudden every image for the sites “disappeared” (wouldn’t be displayed). I suppose it is possible the are corrupt in some detailed way and some update no longer allowed some previous “lax” checking to allow the non-compliant files but it seems more likely that some of thing has gone wrong (but somehow ob_clean takes care of it).