As promised here are the slides from my talk last week on Perlbrew and Carton.

carton_and_perlbrew

I’m excited to be speaking at the Boston Perl Mongers meeting this Tuesday 9 October 2012. I”ll post slides and a summary next week but I thought that I’d post an abstract here as a teaser.  If you’re in Boston and are interested in attending the talk information on  the Boston Perl Mongers meetings is available here.

Abstract:

Managing Complexity With Perlbrew and Carton

Deploying Perl programs to multiple systems can be challenging.  Even when they run the same operating system version, different systems often contain different versions of the same CPAN modules. Different module versions are often incompatible in subtle ways that may not be detected immediately. In the worst case, software works fine on the development machines but malfunctions in production.

Things are even more complicated when deploying to different operating systems or different versions of the same operating system.  Different distribution versions may contain different version of the system Perl and on many systems, the distributed Perl version lags the latest release. Writing for the oldest Perl version on all deployment systems means missing out of newer features, which reduces programmer productivity, and makes code less readable and reliable. Perl has excellent backwards compatibility but some differences still exist.  Ubuntu LTS versions are often still in use after the Perl they distribute is no longer supported by the Perl community. Because Perl is deeply integrated into Debian and Ubuntu systems, vendor patches are usually limited to security issues, and manually upgrading the system Perl is difficult and risky. Thus users of older distributions may encounter program cashes due to internal bugs in a system Perl that they cannot patch nor upgrade.

This talk will show how Perlbrew and Carton can be used to address these problems. I will discuss how the Media Cloud project used Perlbrew and Carton to decouple the system Perl from the application’s Perl and achieve a consistent environment across different machines running different operating systems.

Earlier this week I created a tumblr blog – David Blends. There, I’m posting pictures of smoothies, soup, and other things that I make with my Vitamix blender. Every time I make something interesting in the Vitamix, I’ll post a picture and a brief description.

Over the summer, I participated in a smoothie cleanse and a 10 day green smoothie challenge during which time I had to drink at least one green smoothie a day and post a picture on facebook as proof. The 10 day green smoothie challenge was a great motivator. I’m hoping that publicly sharing my creations will also help me consume more green smoothies.

Part of my motivation was also to experiment with tumblr. I’d know of tumblr, of course, but hadn’t previously had a reason to use the service. So far, it seems like an excellent platform for posting images and commentary.

I may still have the occasional post here about blended creations. But unless something is especially interesting, I’m likely to post exclusively to the Tumblr.

I’ve been using Picasa Web as my primary photo sharing service but I’m strongly thinking of moving somewhere else. My biggest complaint with Picasa is that uploading and organizing photos is too much of a hassle. My secondary complaint is that it doesn’t integrate well with facebook. However, moving to another service is a hassle and I want to make sure I pick the right one. So I’m turning to the Internet was advice. Here are my criteria:

At this point, my default choice is Flickr though a Gizmodo article (http://gizmodo.com/5910223/how-yahoo-killed-flickr-and-lost-the-internet) predicting its demise gives me pause. Furthermore, given the cost of switching, I don’t want to choose a service lightly. Any and all recommendation would be appreciated.

A couple of weeks ago, I had the pleasure of attending Pi-Con and serving as a panelist. Here’s a quick overview of the experience. On Friday, I was on a panel on the future of robotics with Judah Sher and Drew Van Zandt. One of the more interesting topics of the panel was stompy an 6 legged kickstarter funded robot being built by Artisan’s Asylum.

 James L. Cambias gave a to talk on real airships that was so awesome, that I devoted an entire blog post to summarizing it. Susan de Guardiola taught a very enjoyable introduction to cross-step waltz. I also moderated panels on electronic warfare and steampunk costuming.

Conclusion

Pi-Con was a great experience as always. Sadly it will not be held next year because the convention staff need time to recover but I very much look forward to attending in 2014.

Last weekend at the Pi-Con convention, James L. Cambias gave a fascinating talk on historical airships.  This is a summary based on my notes and my memory. DISCLAIMER: I MAY HAVE GOTTEN STUFF WRONG OR MISSED IMPORTANT POINTS. I’M NOT AN AEROSPACE ENGINEER AND DON’T CLAIM TO UNDERSTAND THE PHYSICS OF FLIGHT.

Airships are a staple of steampunk and speculative fiction. Their aesthetic is immensely appealing but their mechanisms are rarely discussed. Cambias’s talk was a refreshing and fascinating look at real historical airships and touched on the engineering challenges of lighter than air flight. For example, burning fuel changes your weight.

The historical highlights began with Henric Giffard (http://en.wikipedia.org/wiki/Henri_Giffard) who created the world’s first airship in 1852 and ended with Zeppelin and his creations in the twentieth century. Along the way, Cambias discussed other significant figures. Santos-Dumont was particularly interesting. He not only created a number of airship’s between 1898 and 1905 but he actually used them to fly around Paris. (Santos-Dumont eventually turned his attention away from airships to airplanes.)  La France created by French army captains Reynard & Krebs was also mentioned. It was the world’s first fully controllable flying machine and used an electric motor which drove it at 12 mph.

Cambias discussed some 19th century American attempts at airships. Dr. Andrews’s Aereon built in 1863 was documented in newspapers at the time. However, modern scientists say its design would not have worked. The speculation is that it functioned as a balloon rather than an airship and that the Andrews got lucky with the wind giving the illusion that the craft was steerable. Marriott’s Avitor was an airship that sadly never came to be. A prototype was built in California in 1869 and flew on a tether.  But, alas, a full sized version was never made. In the 1890’s, there were reports of a mystery airship in American newspapers. The stories even included reports of cows being stolen. In all likelihood this was an elaborate hoax started by bored telegraphy operators and perpetuated by newspapers that freely stole each others articles and cared little for the truth.

The Giffard dirigible
Source: http://en.wikipedia.org/wiki/File:Giffar…

It’s been hot this weekend and since I don’t have air conditioning in my apartment I need another way to keep cool. It is good weather for ice cream but ice cream is high in saturated fat and sugar so I made a healthier alternative using what I had on hand. A homemade fruit sorbet the perfect healthy ice cream replacement.

Here are the instructions if you want to make own.

Ingredients:

1 frozen banana
1 half fresh avocado
frozen tropical fruit mix
frozen mango
1 tbsp organic blue agave syrup

Equipment: High speed blender such as a vitamix.

First add the avocado, then add the frozen fruit, final finally add the agave syrup. Start blending on low and then increase the speed to 10 then to high. Using the tamper push down the fruit to blend it. Continue blending and pushing with the tamper until the desired consistency is achieved. Scoop out of the blender. The sorbet can be eaten immediately or stored until later.

One thing, I like about this recipe is that it lends itself to experimentation and adaptation. For example, I normally use ice but — perhaps because it was a hot day — the stores I went to had none left in stock. No problem, I simply made sure that I used plenty of frozen fruit.

Feel free to experiment but I recommend using bananas and avocado if possible. These help give the creamy consistency that makes this such a good ice cream replacement.

Disclaimer: I’ve only tested this recipe with a Vitamix. I don’t know how the recipe will work with another blender but if you try it please let me know how it goes. The recipe above is my creation but I’m not the first person to suggest using a blender to create a healthy ice cream replacement. Numerous other people have their own recipes. I’m sharing mine here because I hope it will be useful for those who are also looking for a healthy way to beat the heat.

Pictures from HOPE 9

Earlier this weekend I was able to attend my third Hackers On Planet Earth (HOPE). As always, HOPE was an incredible experience. Here are some pictorial highlights.

Hope Number 9

Today I was a seller at the MIT Flea market. Here is a report on my experience. Warning: this was my first time at the Flea and my first time being a vendor in general so future MIT Flea’s may be different. The MIT Flea is held on the third Sunday of the month April through October. The event takes place at an outdoor parking lot on Albany street in Cambridge. As a seller, you drive to the lot and are directed to a parking space. There’s enough room to set up a table or two behind your car to display your wares. The Flea lets sellers start setting up at 7:00 AM but doesn’t open the doors to buyers until 9:00 AM. I got there at 8:45 but found that I had plenty of time to set up before the market officially opened. The Flea charges $20 to sellers and $5 to buyers.

My motivation for going to the Flea was to sell off things that I no longer needed in order to declutter my apartment. I hoped that the Flea would be a good way to sell off a large number of things at once. Ebay and Craigslist are great for selling individual items but don’t really benefit from selling multiple items simultaneously. In the language of economics, ebay and craigslist have lower fixed cost but higher marginal cost while selling at the Flea has higher fixed costs — the registration fee, the time and effort of schlepping there, etc — but lower marginal costs — it doesn’t cost anything to have another items on your table.

I ended up bringing a few high value items: a cell phone, an eReader, autographed celebrity photos, and a projector; and a number of low and medium value items such as an unopened video card and a CPU cooler. I sold most of the low and medium value items and pretty much sold everything that I was willing to let go for $1. Of the high value items, I only sold the eReader.

Part of attending an event like this is the learning experience. Here’s the some of the lessons I learned.

• The crowd at the Flea likes to buy things cheaply. The gentleman next to me was selling two classic Macs to the 1980’s. His prices were well within the online price range for collectible Mac computers (~$500). Although, many people stopped to admire them, no one purchased the computers. I couldn’t help but think that the crowd at the Flea are not the type to purchase expensive collectibles. But he was undeterred and plans to return next month to try again.

• Some people haggle aggressively and obnoxiously. I priced the cell phone based on eBay and Craigslist listings. Some people offered a lot less than those values and most of the time that was no big deal. I simply explained that even with eBay and Paypal, I could make more selling online than what they were offering.  However, a few people didn’t want to take no for an answer to kept insisting I sell it for a lower price. One gentleman even throw some cash on the table and practically demanded that I accept his offer even though I had already told him that he was offering $40 less than the going price on eBay.

• Be prepared for the heat and sun. The Flea takes place in an above ground lot with no trees. Even if it’s not a warm day, the constant sun can get intense. I had SPF 15 sunblock which was better than nothing but not enough. If I go again, I’ll wear a hat or have an umbrella set up at my table like some the veteran Flea attendees.

• Bring food and liquids. Vending for an entire day takes a lot of energy so make sure you’re well nourished. Bring a snack or light lunch and plenty of water. There was only one food vendor and their items were limited to chips, grilled food, soda, and bottled water. I had to walk off site just to get some reasonably healthy food to make it through the day. (There are portable bathrooms so didn’t worry about limiting your liquids.)

• Get there early and leave early. The Flea is busiest right after it opens at 9:00. New people come throughout the morning but by 12:00 things are relatively dead. Although the Flea is open until 2:00, I wouldn’t recommend staying much after 12:00. After the morning, I got few visitors and had no sales.

• Carefully decide which weekends you want to attend the Flea. The word that I got was that the most active Flea’s are the first one (in April) and the last one (in October). The September Flea was said to be the third most active. Although the weather was excellent, I was told that the Flea I went to was comparatively poorly attended. It was also Fathers’ day which may have been part of the problem.
• Have plastic bags. A number of people asked for plastic bags to hold their purchases. If you have a bunch of grocery store bags at home bring them along. Your customers will appreciate it and you’ll be able to rid yourself of some of the bags.

I haven’t attempted to explicitly calculated a return on investment from vending at the Flea but I didn’t think that it would seem like an impressive amount given that it took 5+ hours of my time. That said, I sold enough to more than cover the cost of my vendor’s fee and the process was kind of fun. With the exception of the few overly aggressive hagglers mentioned above, the people I encountered as both buyers and sellers were friendly and interesting. My goal had been largely to declutter and although I was not particularly successful selling my high value items, I did manage to sell off a box worth of stuff that had just been taking up space. There’s also something nice about selling something to someone who really appreciates it even if you’re only getting a $1 for it.

This post is about a problem and a solution.

http://www.makeuseof.com/tag/5-ways-send-files-dropbox-dropbox/
http://www.codingbeaver.com/myblog/index.php/2011/12/09/sugarsync-vs-dropbox-vs-spideroak-which-should-i-choose/
http://gizmodo.com/5828035/the-best-way-to-store-stuff-in-the-cloud