The Humble Programmer – Edsger W Dijkstra

I first heard of Edsger W Dijkstra in the context of agile programming.I was having a discussion regarding agile programming with some friends and explaining Test Driven Development and the concept of first creating tests that can prove show the correctness of the code before writing the code, when a friend mentioned that this sounded a lot like some of the arguments put forward by Prof. Dijkstra in his Turing award lecture in 1972. I found that hard to believe, after all, if this was known in 1972 then why is it only becoming popular now ?

So I started looking up Edsger W Dijkstra and realized that this man was one of the pioneering giants of software programming. He is the father of structured programming and one of the guiding heads responsible for much of the way we program computers today. There is a lot written about him all over the place – I shall focus on his Turing award lecture, that was titled “The Humble Programmer“. In this lecture, Prof. Dijkstra puts forth six arguments on the way software programming should be done. On reading these six arguments I cannot help but feel that this lecture was one of the main inspirations used by the authors of the agile programming movement and design patterns community.

The six arguments put forward in the lecture are as follows –

1. “A study of program structure had revealed that programs —even alternative programs for the same task and with the same mathematical content— can differ tremendously in their intellectual manageability. A number of rules have been discovered, violation of which will either seriously impair or totally destroy the intellectual manageability of the program.I now suggest that we confine ourselves to the design and implementation of intellectually manageable programs. The programmer only needs to consider intellectually manageable programs, the alternative alternatives he is choosing from are much, much easier to cope with.”
2. “As soon as we have decided to restrict ourselves to the subject of intellectually manageable programs, we have achieved once and for all a drastic reduction of the solution space to be considered. This argument is distinct from argument 1.”
3. “If one first asks oneself what the structure of a convincing proof would be and having found this, then construct a program satisfying this proofs requirements, the these correctness concerns turn out to be a very effective heuristic guidance. By definition this approach is only applicable if restrict ourselves to intellectually manageable programs.”
4. “The only mental tool by which a very finite piece of reasoning can cover a myriad of cases is called an “abstraction”. There are number of patterns of abstraction that play a vital role in the construction of programs. Knowledge of these patterns of abstraction are essential.”
5. “A programmer is fully aware of the limited size of his own skull; so he approaches the task of programming in full humility and avoids clever tricks.”
6. “The only solutionproblems we can solve in a satisfactory manner are those that finally admit a nicely factored solution.”

When you go through these arguments you see the seeds for the various movements in programming software today –

• Arguments 1 and 2 are the foundation of principles like KISS (Keep it Simple and Stupid) and YAGNI (You Ain’t Gonna Need It)
• Argument 3 forms the basis of efforts like  Test Driven Development and the Design By Contract.
• Argument 4 leads us to Design Patterns.
• Argument 5 and 6 preaches humility in programming, the use of abstraction to write readable well factored programs – beautiful code

I really enjoyed reading his lecture – I have the lecture here (The_Humble_Programmer)  if you want to read it. He must have been an extremely engaging speaker – a lot of his quotes are available here.

Till next time – Happy Programming !

Update: I have made a couple of corrections based of some of the comments here.  When I wrote that argument 3 is the basis for TDD I meant that in the lecture Dijkstra talks about first finding the structure of a proof and then constructing the program satisfying the proofs requirement. This is similar to the TDD approach of first writing a test and then writing code that satisfies the test.

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What is TED ?

TED is simply a gathering of the remarkable minds to talk about and listen to ideas that they think are worth spreading.  At a glance these are the facts about this organization –

1. TED started out in 1984 as conference bringing together people from three worlds : Technology, Entertainment, Design.
2. It was acquired (in 2001) by a Non Profit – The Sapling Foundation. Under the foundation TED has evolved beyond a conference in Long Beach to a have global presence with conferences in US (TEDConference), Europe (TEDGlobal) and India (TEDIndia). The curator of the foundation (and the conference) is Chris Anderson.
3. The scope of the conference has also become broader to include subject matter, to cover almost all aspects of science and culture.
4. The conference is very difficult to attend and is by invitation only – in fact there have been claims that it is elitist and the folks at TED have responded to this claim.

All this is public record – but, IMHO what makes TED different is – the quality of the speeches and that they are publicly available on the internet.

The speakers at TED range from business tycoons like Bill Gates, Jeff Bezos, and Richard Branson to political figures like Bill Clinton, Al Gore and Gordon Brown to artists like Bono , Ze Frank and Frank Gehry (there are a lot more including Stephen Hawking, Jane Goodall, Nandan Nilekani, ….- you get the idea).  What moves them ? What excites them ? What do they feel is going to change the world ? These are the topics that they are invited to speak on for 18 minutes. There is a TED Prize – 3 winners are chosen every year from the conference and they get support from the TED organization for “One wish to change the world”. I guess there is something about the experience that seems to bring out the best from the audience, and the speakers, because the presentations made here are simply awesome !

The other aspect of TED and indeed the one that made me aware of them their potential is their endeavor to record and publish all the speeches on their website. The website was started in 2006 is constantly evolving with the latest social networking (Chris Anderson is on twitter) and awesome high quality video. This was what really made me go – whoa… and grasp the power of the conference. I suspect this is also what brought TED to the mainstream and captured the imagination of people like me, who would never have even heard of such a conference otherwise.

Some videos worth watching are –

1. Hans Rosling – Best stats you have ever seen
2. Pranav Mistry – Sixth Sense Technology
3. Karen Armstrong – Charter for compassion
4. George Whiteside – Postage Stamp Lab

There is some really inspiring stuff  here – I sincerely recommend that you bookmark this website and add it to your reminder list to visit on a regular basis – get motivated and inspired !!

Article, Video, TED

Quietube – Readability for videos

I was thinking a few weeks back, while wading though yet another banner ad heavy website to get to a video, about asking the folks behind Readability for something similar for videos. I filed away the thought for later and soon forgot about it (I think this is why I am not a millionaire ;-)).  Anyway, while going through other blog posts on Readability the other day I came across this one from a fellow Readability enthusiast from Brazil – right at the bottom was the link to this gem.  Et´ Voila ! Solution found – this is why I love the internet :-)

Quietube is exactly what I was thinking about – its Readability for internet videos !
Even the installation is similar –

1. Go to the Quietube installation page.
2. Drag the bookmarklet on to your bookmarks toolbar or add it to your bookmarks.
3. When you are in a one of the big internet video websites (YouTube, BBC iPlayer, Viddler, and Vimeo are supported) – click on the bookmarklet and you can see the video without any of the comments and distracting fluff.
4. A link is also available at the bottom of the page enabling you to send this view of the video to a friend or save it for further viewing.

The tool is built by BookTwo and from the blog post it seems its a side project inspired by Readability. The tool is currently limited, in that it does not detect embedded videos in other websites (and the error message seems a bit cheeky ;-)) but they are working on improving this. Another problem is that there seems to be no mechanism to report issues to the group like Readability. On the whole this seem to be a useful tool for those who want to quietly watch a video without all the bells and whistles :-)

web 2.0, software, tool, bookmarklet,

Readability – Transform the way you read on the web !

I love reading – I read books, articles, magazines, circulars, just about anything I can lay my eyes on… Naturally, I am a voracious reader in the Internet as well – I have subscribed to a huge number of RSS feeds, and  have a constant stream of Twitter tweets on articles to read.

The problem, I face when reading on the internet is, eye fatigue – I have astigmatism and the varying fonts faces, sizes and colors is a strain – even to normal people with perfect sight ! Couple this with the increasing number of advertising on the top and on the side of articles and you have a situation where the actual content is increasingly obscured. Font sizes are getting smaller and smaller and content is getting squeezed more and more by advertising and marketing clutter.

Of late, I have been using a tool that I found on the web (I saw it on Twitter but I have unfortunately been unable to track who sent it to me :-( ) that has literally transformed my reading experience. It was created by a company called Arc90 and is a Bookmarklet which can dragged onto your browser bookmarks. When you click on it – it  reloads the current page loaded in your browser stripped all extraneous fluff.  Simply the content of the page is shown.

As a web-developer and general internet addict ;-), I have seen a lot of tools and gadgets and I like to think I have a good idea of what works – as soon as I saw this tool I knew this would be awesome. The concept is simple, powerful – elegant.  It is one of those things
that seem so obvious  – when you feel that way – you know you are seeing a work of genius.

What you need to do to get this gadget is  –

1. Go to the Readability installation page
2. Choose from the simple options given there how you want your content to be displayed – the options are simple and straightforward giving you a choice of reading style, font size and margin width (I chose eBook style, large size and narrow margin). A sample text is shown with the formatting you choose so you can play with the options.
3. Once you are satisfied, simply drag the big button marked “Readability” onto your bookmark toolbar (or you can right click the link and choose the bookmark option) and your done !
4. Next time you are on a web-page with a compelling article being obscured by garish ads and decorations, simply click on the Bookmarklet and the page reloads with the content formatted exactly as you want it.

When I first installed it they had fewer options and every once in awhile it would not work – but they have been going from strength to strength with new options and it’s rare to see it not work.

This tool has certainly transformed how I read on the web – I can’t recommend this tool enough!!  So what are you waiting for – go get it !! :-)

PS: It won the NY Times Pogy award for best idea of 2009

web 2.0, software, tool, bookmarklet, font

A podcast review – Software Engineering Radio

I am a fan of podcasting.. video blogging and screen casts are fine, but in terms of convenience and bang for the megabyte – nothing beats a podcast :-). I have been listening to podcasts for a few years now. I am usually listening when walking home from work or doing some chores. In fact I wrote an earlier postabout them along with some of my favorites (at the time).Of late I have listened a lot to a podcast called Software Engineering Radio. Actually, I have been listening to this one for a long time now and it has grown from strength to strength. It was started by a German software consultant – Markus Voelter and is based in Europe (the details are here). There is now a team of people both creating episodes as well as supporting the website. A new episode is published every 10 days and the feed for it is available at the website.

The podcast is about the software engineering and is for professional developers (it says so in the title :-)).  IMHO it is the best podcast for professional developers I have come across.  Markus and his team of volunteers do a great job – the interviews are professionally done and the audio quality is great. The post production is also very well done – in fact they have put up videos about their recording and post-production process. All the recording are released as part of Creative Commons 2.5 license and I think the majority of the episodes are gems worth downloading and keeping.

The coolest thing about Software Engineering Radio and what ultimately makes it such a great resource are the subjects and the people they interview.

The subjects are for the most part about software engineering practice – but they are things that are really useful to ones growth as a software professional. Episodes range from discussions about software development methodology to software languages and tools to computer science research.  In fact there was recently a very interesting episode on the – Difference between Software Engineering and Computer Science.

The people interviewed range from professional software developers and consultants to researchers and academics. Some are giants in their field and others I haven’t heard of (admittedly thats a large percentage of them – maybe because I hadn’t heard of their field in the first place ;-)).

Another thing I would like to mention is the format of the episodes. They are interviews and the team at SE Radio
go to great lengths to prepare and ask just the right questions to
illuminate the topic at completely and extract pearls of wisdom from
the people they interview. I think this format is better than a speech or a presentation because of the interaction between the interviewer and the interviewed.

There is sometimes a problem with the English accent – most of the team are from mainland Europe and have European accents, but it is never so bad that one cannot understand what is being said. In fact one of the things I like about the show are the various accents of people from different parts of Europe, UK and America. It makes the show more interesting to me as I try to guess at the nationalities of the interviewer and interviewed from their accents ;-)

Software Engineering, podcast, review