Entries posted in March 2013

Time passes, Thorin sits down and starts singing about gold.

Saturday, 30 March 2013

This weekend I have mostly been reading Longitude: The True Story of a Lone Genius Who Solved the Greatest Scientific Problem of His Time .

In modern times we divide the earth up into rings of lines, latitude and longitude, as wikipedia will explain.

Finding your latitude is easy, finding your longitude is a difficult process, and it was vitaly important when people started to sail large distances, the book contained lots of stories of sailors being suddenly suprised by the appearance of land - because they'd misjudged their position.

Having four ships, containing garlic, pepper, and other goods of value exceeding the total wealth of the UK, sink all at once was a major blow. Not to mention the large number of sailors who lost their lives.

There were several solutions proposed, involving steady hands and telescopes, etc, but the book mostly discusses John Harrison and his use of watches/clocks.

John Harrison was featured in Only Fools & Horses, as the designer of the watch that made Delboy & Rodney millionaires.

->Time on our hands

The idea of using a clock is that you take one with you, set to the time of your departure location. Using that clock you can compare the time to the local-time, by viewing the sun, etc. Calculating the difference between the two times allows you to see how far away, in degrees, from your port, and thus how far you've traveled.

Until harrison came along clocks weren't accurate enough to keep time. His clocks would lose a second a month, until then clocks might lose 15 minutes a day. (With more variations depending on temperture, location, and pressure. Clearly things like pendulum clocks weren't suitable for rocking ships either.)

All in all this book was a great read, there were mentions of Galilao, Newton, and similar folk who we've all heard of. There was angst, drama, deceit, and some stunning craftmanship.

Harrison was a woodworker, and he made his clocks out of wood (+brass where necessary). Choosing fast/slow-grown wood depending on purpose, and using wood that secreted oils naturally allowed him to avoid lubrication - which improved accuracy, as lubricants tend to thin/thicken when temperature/pressure change.

A lovely read, thank you very much.

In other news I received several patches for my templer static-site generator, and this has resulted in much improvement. I've also started using Test::Exception now, and slowly updating all my perl code to use this.

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Want to fight about it?

Sunday, 24 March 2013

So via hackernews I recently learned about fight code, and my efforts have been fun. Currently my little robot is ranked ~400, but it seems to jump around a fair bit.

Otherwise I've done little coding recently:

I'm pondering libpcap a little, for work purposes. There is a plan to write a deamon which will count incoming SYN packets, per-IP, and drop access to clients that make "too many" requests "too quickly".

This plan is a simple anti-DoS tool which might or might not work in the real world. We do have a couple of clients that seem to be DoS magnets and this is better than using grep + sort against apache access logs.

For cases where a small number of source IPs make many-many requests it will help. For the class of attacks where a huge botnet has members making only a couple of requests each it won't do anything useful.

We'll see how it turns out.

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Handling bookmarks?

Saturday, 16 March 2013

I've a collection of about 500 bookmarks which I've barely touched for a few years. I started organizing them late the other night, because I'd been off work sick for two days and that was about the most I felt up for doing with a computer.

The intention was to "tidy" them, and then setup some way of syncing them across browsers/computers. In the end I didn't like any of the syncing plugins I could find - xmarks, etc - so I decided to take a step backwards.

I'd exported my bookmarks to HTML page, via firefox, before I started, and then later in a fit of pique I deleted the whole damn lot of them.

So now a few years worth of bookmarks are stored in a single HTML file. But wait, we can use revision control can't we? We can host that file on github/similar. We can rely upon merges to deal with conflicts - simple if we just add lines to the end, or delete lines.

Maybe that's the best way to store bookmarks? I updated the bookmark file to read:

<ul>
<li tags="debian, personal"><a href="http://www.debian-administration.org/">Debian Admin</a></li>
..
</ul>

Adding "tags" to the LI-container and then some simple jQuery code gave me the ability to search/filter the bookmarks and auto-populate tags.

A small example placed online here:

The obvious comment is that this makes adding new bookmarks a bit harder, but we'll see.. The javascript works in the browsers I tested, and for those that have none the bookmarks will just be a simple unordered list which should be universal.

I expect the javascript could be improved by a real developer.

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So I'm a year older

Wednesday, 13 March 2013

Last week I had another birthday, which was nice. I'm now all mature, and everything. Honest.

I received a few surprise gifts from friends and strangers alike, which was pretty good. Other than that I didn't do too much.

This weekend I'm going to be using "airbnb" to spend the weekend in Dundee with my partner who is regularly commuting between Edinburgh and Perth/Dundee, to work in various hospitals. With all the commuting time she's not had too much time to explore the actual city, and I've only been there once before so I'm sure it will be a fun weekend.

The templer static site generator got a little bit of pimping on LWN.net the other day, thanks to Martin Michlmayr, although embarassingly I seem to have read the article and repeated the content in the conclusion, and duplicated that in my own comment. Ooops.

Beyond that I've done little coding recently, although I suspect now that nodejs has had a stable release I might do something interesting soon. I don't want to dwell on the failure of Sim City - because I don't run windows and couldn't have tried it even if I wanted to - but I'm pondering the idea of a persistant grid-space where different items can be placed.

I've not tried anything browser-based before, but the popularity of things like minecraft make me wonder if you had an "infinite grid" where folk could store "stuff", and scroll around in a browser you might be able to do interesting things.

Starting small, with a 100x100 grid, and some kind of updated play-by-mail turfwars/drug-war like experience should be simple. But then again enthusiasm is easy to generate until you start working out how you'd interface with the server and what kind of client you'd need.

Now to enjoy some 21 year old whisky and call it a night..

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Testing the blog feed

Sunday, 3 March 2013

My previous entry, about templating, didn't make it into Planet Debian.

This entry is just a test to see if it is my fault.

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