Marcus Ljungblad

I believe we have a culture problem in tech and it's hindering startups to reach their full potential. Tonight #cphftw organised 'More Women in Tech' and it was open for everyone—including men. I decided to head over the bridge to listen.

Here are my loosely connected notes. The main question addressed was: How do we get more women to start and join tech companies?

IBM, a sponsor of the event, noted that only 3% of tech companies are founded by women, and 6.5% of venture backed startups have a female CEO. In the 80s, 37% of the computer science graduates were women, today that figure is 12%.

Louise Ferslev, founder of MyMonii, spoke about early stage product mistakes. In particular, trying to raise money without a prototype and spending too much time talking to potential partners rather than potential customers.

One investor told me "This sounded like a great idea until you asked me for DKK 3m." Don't do that without being able to show something.

There are no super-natural powers needed to start a company, all you need to have is some patience. I particularly enjoyed her golfing metaphor: stop focusing on the end-result, that will only result in crap. Instead focus on every step in between, and look up once in a while.

She also spoke wholeheartedly about surrounding yourself with great mentors and asking them for help when you're in doubt. Hoping tonight's event networking could generate some of those connections.

Gulnaz, CEO and founder of EasySize, talked about the reason's why you may not want to become an entrepreneur. She highlighted

Crazy workload

Lack of financial stability

Emotional roller-coaster

Stress (it's not cool to talk about, but it's real)

You might fail, actually, you most likely will fail

You're at this party and almost everyone is an entrepreneur:

Irrespective of who you talk to, everyone's gonna say it's great. Then they go home being paranoid about everyone else doing so great.

Camilla Ley, CEO of Queue-It, challenged founders in the room to involve coworkers today as many of the next-generation of women founders will come from today's startups:

Include your employees! They are not going to stay with your company forever anyway, and that's OK! Better to have a discussion about it.

Camilla also pointed out that she's more conscious about personal time, paying for meaningless tasks like cleaning and laundry. As well as ensuring she divides house work equally with her husband.

The open discussion finished with coming up with concrete ideas about what we can do, here are some:

Think multi-modal: all organisations must tackle the problem

Use ambassadors at schools and universities

Create interest groups on specific topics (FemaleTechies, RubyLadies)

What are others in this room doing? "I need help with this"

Become more vocal

Give each other opportunities

As a final note, I was surprised that there weren't more men in the audience. Despite the explicit open-call in the invitation:

The lack of women entrepreneurs is not just a women’s issue — it’s everyone’s issue. Everyone in the tech community will benefit from having more women starting companies. [...] This is why this meetup is not “girls only” — everyone is welcome, regardless of gender.

Some comments I picked up after the talks included (paraphrasing):

"It was great that everyone was so honest."

"I'm here to see what other women are doing in Copenhagen."

"A guy asked me if any other men would show up."

"I like the environment, it similar to that of Founder's House."

Thanks @ullerup, @lferslev, @gkhusainova, and more for organising and letting me listen.

Around eight months ago I wrote about the lack of diversity amongst speakers at events under the Foo Cafe umbrella. One suggestion to tackle the problem included adopting a code of conduct. Another to increase outreach, actively inviting a diverse set of speakers at the events. So what has happened since?

The good news, Foo Cafe introduced a code of conduct. They have hosted many many more events. And they have expanded their team.

The bad news, diversity numbers hasn't improved.

5 women, 3 unknown, and 58 men speaking at a total of 50 events.

All "Code", "Innovation", and "Cutting Edge" events that FooCafe hosted since August 18, 2014 through February 28, 2015 are included and I counted the number of men and women speaking at each event (determined by speakers' names*, sometimes by googling).

In total I included 50 events during the time period. Those events that were marked cancelled and those that fell in the category "get together to hack" I excluded. One event had speakers of both genders. I also opted to exclude the conference Beauty in Code (which, by the way, had 100% male speakers). In three cases I was unable to determine who the speaker(s) was.

In the last measurement I counted 5 women, 11 unknown, and 41 men in 46 events.

To be concrete: that's no improvement at all.

Critics pointed out that simply introducing a code of conduct isn't going to solve any problems. They are right, and the numbers above confirm that.

Critics also pointed out that Foo Cafe may have other priorities, like finding a sustainable business model. They may also be right.

And finally, a few were quick to point out that speakers may not reflect attendance numbers. I have no insight on that and I'm unsure if Foo Cafe tracks this.

What shall we do?

I'm not sure. I think DemoDag and StartupDojo are two of the better recurring events hosted at Foo Cafe. The co-organisers Björn Söderqvist, Erik Starck, et al manage to, as far as I can tell, encourage a welcoming environment and culture where everyone can speak without being questioned. Perhaps other organisers can learn from them?

Paulina (@pauspling) has a great number of suggestions in her post "How to get great women to tech and startup events" which I strongly recommend reading.

Foo Cafe, what's next?

Last week Foo Café made two significant announcements: the implementation of a Code of Conduct, and a manifest detailing what Foo Café is and stands for.

In the midst of a growing Swedish, and international, focus on diversity and sexism in tech, Foo Café is setting an excellent example for other organisers (hint: #sthlmtechfest) to follow. Their getting noticed and the speaker list for this autumn is already looking better compared the spring's.

Thomas Frostberg, business journalist and creator of #tackanej, highlighted Foo Café's ability to listen to criticism in his latest column (in English).

Rakt motsatt attityd har Malmöföretagaren Michael Tiberg visat efter att ha fått kritik för att hans arrangemang Foo Café haft kraftig övervikt av män bland presentatörerna. Han arrangerar tillsammans med andra företag och organisationer återkommande träffar för personer i IT- och webbindustrin och kommer nu att arbeta för att nå större mångfald i arrangemangen.

And listening is tough. Often I stubbornly refuse an idea in my head only to later realise that a certain ego is just standing in the way. In many cases, it is because I haven't fully understood the perspective or motivation of the other person's opinion.

"You can learn from anyone as long as you dare to listen. But listening is really really hard sometimes." @michaeltiberg @_FooCafe_

— Marcus Ljungblad (@mljungblad) August 27, 2014

So while the code of conduct provides a foundation for a safe environment, which is crucial for learning, the manifest addresses the more abstract, the culture if you like, of Foo Café. It establishes common values among participants and organisers of the events. It helps us understand why we attend and come back.

A section that I particularly like in the manifesto is "Everybody matters". To me, it captures the essence of Foo Café's existence.

You can learn from everyone, we have all different experience that we can share and teach.

Here's a selection of "stuff" that I've stumbled upon over the last two weeks that I think is worth remembering.

Prototyping Everything

A great talk by @robfitz at The Conference. I read his book The Mom Test earlier this year and in the talk he goes through its major point: asking questions that don't suck.

Watch the talk at The Conference

Flygpoolen.se's customer service failure

Hej @mljungblad, det här är en social medieplattform och vi har tyvärr ingen möjlighet att besvara kundtjänst ärenden kontakta kundtjänst

— flygpoolen (@flygpoolen) August 20, 2014

Failing at Microservices

This article highlights some hidden challenges that should be considered before implementing a microservice software architecture.

Building your own Lisp

Bodil Stokke held a talk at Foo Cafe earlier during the year. In it she explains how to build your own functional programming language.

TNW's disassociation from Pavel Curda

Sexism is never OK and there have been far too many occasions that, when brought to light, haven't been handled appropriately. The Next Web, however, did a good job when it turned out investor and contributor Pavel Curda during several occasions had behaved appallingly against women.

As one of many wanderers on the Internet I stumble upon pieces of work, writings, code, photos, or just random stuff that makes me think. Some of it is crap, some of it I couldn't care less about, but some of it is amazing and totally worth sharing and remembering. Since my attention span is reaching that of a goldfish I wanted to find a more structured way of taking notes of these things. This bi-weekly curated list is an experiment and attempt to solve this problem for me.

I'm still working out the criteria for 'stuff' to get listed here, but this is what I've got so far:

The content speaks to me somehow, whether I agree or disagree with it doesn't matter.

It's something I'd like to remember (to do, to avoid, to share, or simply to think about).

I emphasise, I may not agree with the content, but I think it is important enough to remember.

So here's to the first bi-weekly!

A job ad that doesn't suck

KnowYourCompany posted a job ad looking for a new Rails programmer (and a chance to become CTO if things work out well). It's a personal ad!

Dear programmer who cares about doing meaningful work

So it begins and continues with a brief introduction to the company's purpose, what to expect during the first few months, and the personal traits of the person they're looking for. Here's me hoping they find the right person!

Unexpected job ads

Relatedly, @MandaMeh found a sweet place for a job ad by Soundcloud.

Smartest place I've ever seen a jobs page advertised. #SoundCloud #jobs pic.twitter.com/96lWq9w1Cg

— Mehul Mandania (@MandaMeh) July 29, 2014

Hacker School's subtle -isms rule explained

Allison Kaptur does a great job at explaining the last of four Hacker School's social rules: No subtle -isms. All rules are great and I'd love it if all companies and organisations I work with could have something similar.

Our last social rule, "No subtle -isms," bans subtle racism, sexism, homophobia, transphobia, and other kinds of bias. Like the first three rules, it's targeting subtle, accidental, mildly hurtful behavior.

Read about the environment and social rules in Hacker School's manual.

Getting more women to tech conferences

This is an on-going discussion, but two posts have caught my attention recently.

Putting an End to Conferences Dominated by White Men

How to get great women to tech and startup events

In a recent post, I called out Foo Cafe, a "conference every day" in Malmö on this and they're taking steps to improve the situation there too. Awesome!

Vision, risk, and failure

Mission Critical Innovation - Dr. Jeff Norris

What can we learn about innovation from great inventors and explorers who risked everything to change the world? Is it wise to embrace vision and take risks when so much is at stake? Can you afford to be innovative when failure is not an option, or can you afford not to?

Also, his storytelling is impressive!

Connecting The Dots

I've begun writing blog post drafts using Draft which is developed by Nathan Kontny. Then I found out he has written an inspiring piece called Dots.

All conferences and events today provide ways to interact with the audience through social media. That includes the audience physically present at the event and, perhaps most importantly, those who are not able to attend.

Right now the World Scout Youth Forum is taking place in Slovenia and two Twitter accounts, @worldscouting and @slovenia2014, are providing most of the coverage of the event. That's great! However, the their story is lost in river of tweets from the other accounts I follow. The frequency of tweets (tweets which are often hard to grasp unless you're there) is so high that it is annoying and I finally filtered out all tweets from the two accounts.

This is unfortunate and obviously not the intent of the "tweeters".

An alternative method

Instead, I recommend setting up a separate live-feed for high frequency coverage. @frick and I have successfully tried and done this during several events we've covered together. There are at least two ways to do this: through an event-specific account (less preferable), or through a dedicated live-reporting system (most preferable). We've used CoverItLive with success.

Such a system allows your readers to follow a structured narrative of the event. It is persisted and kept in one place. It is not interspersed with tweets and noise from other accounts unrelated to the event.

You are not limited to 140 characters. Short is sweet they say! But the tight limit is, for example, a little restrictive when you want to quote H.M. The King of Sweden at an event on youth leadership (photo below).

And third, and on being inclusive, people not accustomed to the "Way of Twitter" can follow along too. This is one reason several newspapers have started using separate systems for live coverage of news.

The goal is to make it easy for those with even the slightest interest in your event to follow the activities without annoying them. That can be a fine line to walk though.

Today Foo Cafe hosts the last two events of the season before taking a summer break. Since January the umbrella organisation for basically all tech events in Malmö have hosted 46 tech events* with at least 57 speakers. Of those speakers, 41 are men, 5 are women, and 11 are unknown. That’s a stunning 9% of women speakers. NINE percent! We can obviously do much better than this next season. Here are some ideas what Foo Cafe, its partners and you can do to help improve the situation.

For those who don't know about Foo Cafe, they partner with companies, user groups, organisations and individuals to bring the tech community in Malmö together. The events are almost always free for attendees, there is usually drinks and food served, and everything is financed by the companies Foo Cafe partner with.

Foo Cafe is THE place for meetings of all sizes, interests and levels of expertise within the media and technology arena. Planned or spontaneous, it’s up to you.

Clear paths and actions for improving diversity will allow Foo Cafe, its events, and the Malmö tech community to reach new levels of awesomeness!

Why do we need diversity?

Out of all the events I have attended this year, I can count the number of female participants across all those events on two hands. Often it is the same people attending too. Diversity is more complex than just bringing in more women, and we shouldn’t do it just for the sake of having more women attend. The statistics above only call out the ratio between men and women as that is what I could somewhat reliably count.

When you don’t really understand why having more women in technology is important, you don’t extrapolate and realize that having more of every underrepresented minority group is the true goal. — Kat Li, Why are you supporting women in tech

Increasing diversity amongst speakers will, I’m convinced, bring diversity amongst participants. It’ll bring new ideas to our community, and those ideas will be gauged by a broad and diverse set of minds. It will increase the talent pool that companies, many who are sponsors of Foo Cafe, can recruit from. And, I believe, we’ll have a lot more fun and learn way more than today.

Detta gör mitt liv lite tråkigare: Alla techtalks (oftast av män) som alltid _ALLTID_ alltid refererar till utvecklare som män.

— Olgatron (@olgastern) 22 april 2014

What can Foo Cafe do?

Foo Cafe should adopt, and enforce, a code of conduct. All events hosted at Foo Cafe must adhere to it. Adopting a code of conduct is a statement that abusive behaviour is not OK. It lays the foundation to “be excellent towards each other” as Ana succinctly put it, and provides the organisers a clear mandate to address inappropriate behaviour, as well as a way to tell people to get lost if they don’t behave. The goal is to create a safe environment for everybody. Here’s what an organiser of !!Con had to say about PyCon’s code of conduct.

@mljungblad @b0rk @lindsey @lfranchi It’s easy to enforce, covers most of the bases, is simple and clear, and has been used to great effect

— Alex Clemmer (@hausdorff_space) 22 maj 2014

Foo Cafe should actively and continuously invite speakers with diverse backgrounds. Without doubt, Foo Cafe has a tremendous network. It is not enough to just want a diverse group of speakers, you have to actively encourage it. Specifically ask people if they’d like to talk about their latest passion.

OH: @zmagg: oh my gosh. outreach works.

— Julia Evans (@b0rk) 16 april 2014

Foo Cafe can seek help from the community and experts. Foo Cafe, as we know it, only exists in Malmö. They’ve done wonders for the tech scene here and rumour has it that Stockholm is dying to have a Foo Cafe too. There’s nothing wrong with asking for help.

What can sponsors of Foo Cafe do?

Sponsor only events which have a code of conduct in place. Consider to pull your company’s sponsorship of Foo Cafe if they don’t establish a code of conduct. This implies that your organisation understands why a code of conduct is needed. If not, perhaps an internal review is in place too? I first saw this suggestion in a post called What Can Men Do by Shanley.

Get your company to only sponsor events with a code of conduct. These policies help to build events where women and other underrepresented groups are safe and welcome.

Educate your employees about diversity. There are several consultants and resources for companies that want to improve. A quick search gave me these: GenderPerformance, Eductus, AllCompetence, and Rättviseförmedlingen. There are surely more!

Encourage women to speak at events. Even if it is at other events than Foo Cafe! Another way is to suggest that women add their names to one of Rättviseförmedlingen’s many lists, like Apputvecklare, Civil engineers, Programmers, or Web Developers.

What can you do?

Help Foo Cafe by recommending speakers. Despite their magnificent network, they do not know everyone and obviously the current set of attendees consists a pretty homogenic group. Widen their net by reaching out in your own networks. See a colleague at work doing something awesome? Ask if she would like to present it in a user group or other event at Foo Cafe.

Give Foo Cafe feedback after EVERY event. Improvement comes through continuous constructive feedback, and it is our responsibility as participants to provide this feedback. If you don’t like beer and pizza at every event, tell them! If you think the times suck, tell them! If there are too few female speakers, tell them!

Summing up

Changing the situation described above requires some effort from all of us. Even though I’ve been aware of the problem for some time I haven’t had a clear idea of what to do about it. We (men) need to start talking about the problem and the actions we can take to improve the situation.

Lets help Foo Cafe and ourselves for next season of tech events! I’ll promise to start doing more of the above and I’ll do a follow-up post later this year to see how we have improved. Foo Cafe appears willing to improve too.

@mljungblad great question. We are trying to get more female attendees at our tech events. Ideas are more than welcomed.

— Foo Café (@_FooCafe_) May 27, 2014

Give them your best ideas!

Thanks to Olga, Joakim, Per, Erisa, and Maria for reviewing early drafts of this post.

* I selected all the events tagged “Code” and “Cutting Edge” as these are, primarily, the type of events I attend. It would be interesting to check the other types of events too. Also, speakers are counted for each appearance they made. That, unfortunately, makes it a total of four women presenting at one or more of the 46 events.

There is something like HackerSchool's Thursday presentations in Malmö and I only just found out about it! @bjorn_js started* something close to it called DemoDag and tonight was the third time it ran featuring several great hacks from people in and around Malmö!

Enrique presented iColorama, an impressive photo editing app for iPad with hundreds of brushes. He built the entire app himself and has more than 20 super-active beta testers that he trusts as "product owners". They tell him what to do and he'll do it.

Vesta built a cobra using only steel wire! I still don't understand how her fingers survived that. Less (no?) programming involved, but it's always great to find inspiration from vastly different areas. She also announced her own portfolio website.

Marco demonstrated a build tool for web projects that he's been building called PoliteJS workspace. It looks impressive and his goal is to make web development even faster and easier.

Jeremy showed a visualisation of where music artists play the most around the world called Music Globe.

Babak got tired of searching job posting on various aggregate sites and often finding duplicates. With his background in machine learning he hacked a career-matching application called Careerwi.se.

Dharam wanted to explore the new APIs in HTML5, especially the web audio API, and built Clicksonified, an app that plays popular content on the Internet. Fun way to generate music (quality will depend on popularity)!

What I enjoyed about DemoDag is that you could demo anything, as long as you built it. It's a place to show stuff that works and things that you've learned.

Next time I feel that we (as a community) can be more open to incomplete hacks and leave things like "have you considered making it a product" to other great events such as StartupDojo. The value is in sharing, learning, and celebrating the joy of building things. Also, I should have prepared a demo of something!

* Björn will point out that it started in Copenhagen and he merely forked the concept and brought it across the bridge.

That's a bold claim! As a backend developer I frowned upon it thinking "Uh, come on, of course faster database queries matters more!" The quote comes from Steve Souders rules and best practices for making websites faster and is reiterated in his book Even Faster Websites which I spent a fair amount of time diving into over Easter. Here's some of what I've discovered in the world web performance so far.

Even faster requires more work

Souders' second book on web performance builds on the rules he found during his time at Yahoo. He lists 14 rules that will make your website faster and most of them are so simple to implement its almost silly that not everyone is doing it. They range from the more obvious "Minimise HTTP requests" to more obscure "Configure ETags". Yahoo maintains an up to date list and good explanations of all the best practices and rules.

I love the fact that most, if not all, of the initial tips are easy to implement. In his second book, however, it does become more complicated. Solutions includes rewriting Javascript to, for example, load scripts asynchronously, making the code itself more efficient, or flushing the document early. It's tactical to include Douglas Cockroft's chapter on Understanding Ajax Performance first so as to not waste time implementing some of the more advanced optimisation techniques. His chapter essentially promotes a big-O analysis of your website to find what makes sense optimising.

Either way, installing the YSlow plugin is straightforward and is a super easy method for determining what you should start focusing on.

The Prince of Performance: Caching

All modern web browsers cache content heavily. The difference between loading a website the first time and second time can be enormous if done right. Aftonbladet.se, for example, is a notoriously bloated site that on the first page load downloads close to 2 Mb of data.

Aftonbladet relies heavily on front-end caches (Varnish) and CDNs. Inspecting the HTTP requests on the second page load, i.e., with the cache primed, most, if not all, images are loaded from my browser's own cache. There are in other words several layers of caching at play here. A quick look at the HTTP headers reveals the Cache-Control header which in this case tells the browser to cache the page (the private directive). It also says that proxies and intermediary caches must not cache the page.

HTTP/1.1 200 OK Server: Apache-Coyote/1.1 X-UA-Compatible: IE=edge,chrome=1 Content-Type: text/html;charset=utf-8 Vary: Accept-Encoding,X-AB-Device-Type X-Varnish: 1951083729 Via: 1.1 varnish Cache-Control: private,s-maxage=0 Date: Tue, 15 Apr 2014 10:28:40 GMT X-Varnish: 375084195 375015226 Age: 85 Via: 1.1 varnish Connection: keep-alive Set-Cookie: X-AB-Device-Type=desktop; Expires=Wed, 01-Jan-2020 00:00:01 GMT; Path=/; Domain=.aftonbladet.se

Interestingly, this is different for image content which are static and, hence, are more easily cached. The initial response headers from an image has the following header Cache-Control: public, max-age=3456000. This means that both the browser and intermediate caches should cache the content. Subsequent requests to load the page (and images) include the If-Modified-Since request header.

GET /image/16729981/76/normal/0156a2cea5d11/johan_hakelius_white.jpg HTTP/1.1 Host: gfx.aftonbladet-cdn.se Connection: keep-alive Cache-Control: max-age=0 Accept: image/webp,*/*;q=0.8 If-Modified-Since: Tue, 28 Jan 2014 13:06:13 GMT User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_9_2) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/34.0.1847.116 Safari/537.36 Referer: http://www.aftonbladet.se/ Accept-Encoding: gzip,deflate,sdch Accept-Language: en-US,en;q=0.8,sv;q=0.6

Initially I spent a lot of time reading the RFC2616 for HTTP to understand the Cache-Control header, but I find Mobify's resource much more accessible.

Content is king

In the end I cannot help but think that these tricks are all irrelevant if we don't deliver the right content. Souders' tips are all great given that we know that the content we send in the tubes are right. Even though I'm impressed with Aftonbladet's development team, I don't visit their site (other than for technical personal development reasons). And here's why

They may be the sixth most visited website in Sweden and that entitles, no, forces them to use many web performance tricks, but they are certainly not my top choice given the bloat.

In summary, here is my naive priority list for future high-performance web development:

Deliver the right content

Employ best practices

Cache it

Photo by Sebastian Höglund

This weekend I participated in my first hackathon ever: Hackaway organised by Ted Valentin, Martina Elm and Jonny Strömberg and sponsored by Schibsted. For those of you, who like me a few days ago, don't know about Schibsted it is the company that owns Aftonbladet, Svenska Dagbladet, Omni, Blocket, Hitta, to name a few. Naturally, the theme of the event was Hack the News. If you're curious about the hacks, Anders Berg, CTO at Aftonbladet, has a list of all of them on their development blog.

So what was it like?

Tobias Ahlin captured part of it in a tweet.

Participating in a hackathon at a secret location. Came here by boat on Friday. Judges just arrived by helicopter. No idea what's happening.

— Tobias Ahlin (@tobiasahlin) April 13, 2014

If this is what all hackathons are like why haven't I attended one before?

What made Hackaway great?

Hackaway took place on an island in the Stockholm archipelago called Ekskäret. The organisers made an effort to have a relaxed and open spirit by encouraging participants to take breaks, enjoy the scenery, and by choosing a location which shared a similar mindset. There was a gender balance and participants had widely varying backgrounds. Developers and designers from the sponsoring companies and the organisers also participated in building hacks. On top of that, we got great and healthy food served by Matskolan.

My skepticism towards hackathons have often been the unhealthy focus on competing, rather than developing something innovative and useful 1. This comes as no surprise to people who know me, I'm not a competitive person and don't enjoy competitions. That said, I believe Hackaway managed to find a balance for those that enjoy competitions and for those who don't.

Future hackathon organisers

Sponsors are important but they are nothing without the participants. Hackaway made no (to me visible) distinction between anyone. Except maybe the judges.

On that note, while flying the judges in by helicopter is pretty "out there", this matters little to the quality of the hacks.

Don't bother about cash prizes. Fame and glory is worth so much more. My team didn't win the cash, but more importantly we (everyone) won a lot of knowledge and many new friends.

Location matters. A company's shiny fancy office with Fussball and a ping-pong table might be cool, but you'll never beat this:

OmniLingo is an app to help users discover related news in other languages and was conceived at the hackathon Hackaway together with Ana and Pernilla.

The applications are manifold but some of our goals was to

get users closer to the source,

find new ways to discover content,

target multi-lingual news consumers.

We built the app using Django/Python and deployed a prototype on Heroku. It uses articles from Omni.se (caveat: articles on the deployed prototype are static), translates tags using the Yandex translate API, and finds related stories using the Feedly API.

As it turns out, translations are difficult. Finding related content is also difficult, and combining the two yields some very interesting results. For example, related articles to the French president Francois Hollande more often than not yields results about the Netherlands. Irrespective of which language you choose to search in.

In preparation for a new gig I'm reading up on the terms Domain-Driven Design, Command-Query Responsibility Segregation, and Event Sourcing. Here are a list of useful texts and talks that I've discovered so far. If anything is missing please leave a comment.

DDD

Eric Evans: What is a model? - "A model is not a UML diagram nor a certain layer of the software. [...]. It is a system of abstractions, it describes selected aspects of a domain, and can be used to solve problems related to that domain."

Eric Evans: What I've learned since the book - slightly longer talk on Eric's findings since he co-authored the book on DDD.

Eric Evans: Domain-Driven Design - As far as I can tell, the book on DDD. Haven't read it though.

Aggregates in DDD - is a pattern which clusters multiple domain objects into a single thing. There are a bunch of rules for the pattern which I've yet to figure out, but these articles gives a start (thanks to @morganhallgren for the tip).

CQRS

Command-Query Separation - although first defined in a book by Bertrand Meyer, Fowler makes a great job explaining CQS, the predecessor (sort of) to CQRS.

Command-Query Responsibility Segregation - the term is coined by Greg Young (more links below), but again described well by Fowler. Builds on CQS. "At its heart is a simple notion that you can use a different model to update information than the model you use to read information." Moreover, "CQRS allows you to separate the load from reads and writes allowing you to scale each independently" is something I have studied previously, but don't remember using this term for it before. Neat! 1

Udi Dahan: Clarified CQRS - Command-Query Responsibility Segregation "explained". Two significant components Dahan addresses that others have left out are collaboration and staleness. 2

Greg Young's summary on CQRS - The "invetor's" own summary of the CQRS pattern. Perhaps the most straightforward explanation I've seen so far, but flies over some important aspects of what the pattern means for the data model in my opinion.

CQRS pattern explained by MSDN - Good and detailed description of the pattern. Also includes a helpful section on when not to use it (and it has pictures).

Event Sourcing

Fowler on Event Sourcing - The gist in one line: "Capture all changes to an application state as a sequence of events." Two notions I find particularly interesting are Temporal Query and Event replay. The post also includes a good list on some challenges with Event Sourcing.

Event Sourcing explained by MSDN - The section on Performance, scalability and consistency is useful.

EventStore - the basics of storing events rather than objects. "[...] data is not persisted in a structure but as a series of transactions."

A deep look into the Event Store - talk by Greg Young from the Oredev conference, Nov 8, 2012.

Why use Event Sourcing - one of Young's better posts and not at an introduction level. He discusses some subtle, but important, aspects of using an Event Store (as opposed to two stores) as data storage (thanks @larskrantz).

Additional notes

"Focus relentlessly on the core domain" - Evans

"CQRS is not a top-level architecture. CQRS is something that happens at a much lower level, where your top level architecture is probably going to look more like SOA and EDA." - Young

Aggregates are composed of smaller events. E.g., a purchase order contains line items

I'd read Werner Vogel's eventually consistent post before, but stumbled upon it again and reread it. It's good.

Examples in C# on CQRS and Event sourcing

Akka and event sourcing - stumbled across a tweet from scalarconf and I spotted this presentation by Konrad Malawski.

Description of EventStore's architecture

"If you sat down with them [a customer], explaining the long-term value of having an archive of all actions in the system, and they said OK, build this into the system from the beginning, that would be fine." - Dahan

Having read above, I have a feeling that there is a strong overlap with the "Reactive movement". Perhaps not surprising for the initiated, but I had not considered its history beyond that of functional programming before. So here's some food for future thoughts: Reactive Design Patterns, Reactive Manifesto, SEDA, and Retrospective on SEDA.

[1] This may also mean that industry have come up with a marketable name for something researchers have been thinking about for a long time already.

A few days ago I spent time improving the configurability of Elis, a software platform that is built in Java and uses the OSGI framework. OSGI has many quirks and is not always the most straightforward when it comes to working with it (I can in particular rant about the tool support for managing dependencies). Anyway, a part of the configuration framework returned a particular type of Java that I hadn't worked with, even less understood, before: the wildcard type.

Lets start with an example. To retrieve a configuration you do the following:

Configuration config = configAdmin.getConfiguration(SERVICE_PID); Directory<String, ?> properties = config.getProperties();

What's the ? doing there and what does it mean? Turns out it's more generic than using Object and the Java documentation says it represents and "unknown type". You may use it to, for example, write more flexible methods that can operate on a range of types.

using a wildcard as a return type should be avoided because it forces programmers using the code to deal with wildcards

Now, besides this remark from the Java docs, how does it actually work? Here are four ways to iterate over a list of objects or unknown types.

The first two methods are self-explanatory. Without casting explicitly to an Item in process1(...) we cannot use any methods from the Item interface, but our items list may contain any type as long as it inherits from Object. In process2 we are more restrictive and only allow items to contain objects of type Item which means we can use it directly as such.

The third case wasn't immediately clear to me. It turns out you can iterate over items as Objects too and the list can contain any object too (as long as they are the same?) Why is that useful and what's the difference? The bytecode of the two functions (I pasted one of them below) are identical:

(javap comes with the JDK and enables you too look at compiled classes' bytecode.)

You cannot, however, instantiate a list with the generic type <?> and this is because the compiler cannot know which type the objects in the list will be. Another way of looking at it is that the method can accept anything, but the caller must always know (at least something) about the type. Hence, these three are legal new ArrayList<Object>(), new ArrayList<Item>(), and new ArrayList<SpecificItem>().

The <?> type on its own may not make a lot of sense in practice (unless you have some way of safely processing any type of object inheriting from Object). Therefore it is possible to limit the possibilities of the wildcard type. Java calls this bounds. In process4(List<? extends Item>) the list may contain any type which is a subtype of Item and it is called "upper bounded". This means that if you are trying to pass new ArrayList<Object>() the compiler will yell at you. Conversely, if the method argument was process5(List<? super Item>), then new ArrayList<SpecificItem>() is illegal. This is called, not surprisingly, "lower bounded" wildcards.

Since I got back from HackerSchool (which was absolutely amazing by the way) I've begun taking up jobs as a freelance developer. While it's tempting to apply for "real" jobs, and I did interview with some that resulted from contacts from HackerSchool, I'm not entirely sure where I want to be and there seems to be some adventure in going on your own. I like adventures.

Running on your own

Getting up to speed as an independent contractor so far have been both a fun and scary experience. It's certainly a mind-shift and explaining what you do suddenly feels a lot more complicated. It's scary in the sense that I have no idea what project I'll be working on next. But that is also the best part about it.

Initially there was a bunch of paper work that needs to be sorted out. Luckily in Sweden you can do almost everything online and I already had the necessary bank and payment accounts in place. The most annoying aspect is figuring out all the terminology. First time going through the documentation took me quite some time.

Things I've noticed so far

I keep track of time much more closely than before. Lyndsey, a fellow HackerSchooler, recommend HarvestApp and I really like it. Especially for it's interface and uncomplicated features. I have it set up to record four different types of time: Meetings, Programming, Architecture/Documentation, and Pro-bono work. Each slot of time that I record I annotate with a short note on what work was done. The detailed report is attached as an appendix with the invoice sent later. The level of detail may not be interesting for those paying, but it comes from my father complaining about the consultants he hires and their lack of transparency.

Since I bill by the hour I'm also much more aware on how I spend my time. Some people have warned me that this may wear off over time and that you do not feel as conscious about it later. We'll see how it goes.

As far as I can tell there's a level of freedom too. This is likely more in my head than actually so. The responsibility compared to being employed might even be higher. But it feels kind of nice in a way to know that it's ok to take only a 60% gig and have time left for your own projects.

A note on interviewing

During the last few weeks Hacker School alum Lucas has been making rounds on the Internet as Venmo's front figure. He's currently featured on a number of New York City subway ads and an internet version came along shortly afterwards. Venmo want to make payments between friends easier. In Valley terms, they're social payments. Since I'm not eligible to register for Venmo I cannot say how well it works, but if taking my friends' words for it counts, then this says a lot:

You can just Venmo me the money later.

That's a pretty strong statement! People seem to love it.

Now, let's jump across the pond again and back to east Africa, to Kenya actually. M-pesa, or mobile money in plain English, dates back to 2002 but its current form took shape around 2007. There are equivalents in most east african countries and the total transactions of Uganda alone reaches billions of shillings (millions of dollars) monthly.

As a visitor I can buy a local mobile number for 2000 UGX (less than a dollar) and with a sim in hand, I can use any phone including my old black and white Nokia backup phone to sign up for a mobile money account. Transferring money to the account is as easy as visiting any local mobile money dealer. In a little under an hour I have my own bank account. You cannot do this with Venmo yet.

What for you ask? Here are some things you can pay for with mobile money:

a safari tour to Murchison Falls

the water bill

prepaid electricity

(il)legally downloaded movies

vegetables from the market

transfer money to your friend who paid your half of dinner

or, simply withdraw cash

That's a lot more than social. In rural parts of Uganda owning a phone is more common than having running water. Hence, the mobile phone is already an established piece of technology in most people's lives.

What lies ahead? As a developer, I've found few tools and documentation for building applications that integrate mobile money. Mobile operators are certainly in a power position, controlling who and what gets access to APIs (none which are open to my knowledge).

But imagining that this changes, and the Stripe of mobile money comes around, future businesses of the east african markets (and many more) have lots to capitalise on. There are already millions of registered users in the region and they are well aware of how mobile money works. A future where mobile money trumps the plastic cards we carry around in our pockets is not all that far-fetched.

As smart phones also slowly make their way into the market it'll be interesting to see how the old-fashioned interface of USSD and SMS changes. It may be intuitive on older devices, but don't feel natural at all on a smart phone.

Thoughtworks wrote this about USSD and SMS on their Technology Radar recently:

58% of all phones sold last year globally were feature phones. In many developing countries, this is an even larger majority. If your market requires you to develop for these areas, you need to develop with this constraint in mind. These phones use SMS and USSD as a user interface. SMS is a long standing technique for sending messages, and USSD allows you to send SMS like messages in a secure session. You should look at USSD and SMS as another UI and UX platform and treat them as first-class citizens.

The user experience may be the only area where Venmo still is ahead of the curve.

I'd seen them at gas stations, outside bigger malls, at the biggest traffic junction, and a few lonely ones here and there. Men (because it's usually men for some reason) carrying large packs of bootleg DVDs trying to convince you during a brief 30-second stop that Adore is the best love movie out now or that you look like you need some action.

While they might be cheap, 1000 UGX per movie (0.4 USD), quality is far from guaranteed. If you're lucky the CD works. If it does, you hope it is not a telesync copy. If it's a really good day you might even see the end titles.

But with a little entrepreneurship, a good location (inside Kisementi mall), and a broadband connection you can change the game. The picture above is from the favourite video shop in Kampala. If they don't have what you're looking for in store (i.e., sitting on a hard drive somewhere), make a request and come back a few days later. We had requested season three of an an older TV-series that we came to pick up. The price tag? 4000 UGX for the entire season.

What struck me was their professionalism. Compared to the men at the traffic junction, which admittedly more closely represents my bootleg stereotype, this store had taken piracy to a new level. You pay twice the price, but you get better service, and way better quality.

The F'13 batch of Hacker School ended. I left New York and headed to Kampala. Kampala and New York are two strikingly different cities. Over the next few posts I hope to hilight a few of those differences - starting with electricity.

Like buying credit to top-up your phone to make calls you buy electricity credit to run your apartment. Prepaid electricity! On the wall just inside the entrance door is a small digital panel with a keypad. The panel shows how many KWhs you have left. When it reaches 0, you are out of electricity.

The normal flow to ensure you have juice in your sockets goes like this:

The panel on the wall starts beeping, annoyingly telling you that you're soon out of KWhs.

You head to the closest supermarket where there's a hole in the wall (photo above).

"I want electricity for 50000 Ugandan shilling" No idea what this translates to in KWhs.

In return you get a code with electricity credit (exactly like a phone top-up).

Back home, enter the code on the panel, annoying beeps stops and you can hack away again.

This is brilliant for, at least, two reasons. First, Ugandans are used to the top-up/prepaid kind of thinking. Surely there are other methods for paying for things and services, but buying airtime (more on that in another post) and X thousand of something appears extremely common. You do it for your phone or when you go to the market: "3000 tomatoes, please."

Secondly, and perhaps more importantly, you become shockingly aware of how much electricity you consume. I'm notoriously bad at switching off sockets and appliances on stand-by. Here, maybe I might learn a lesson or two. Electricity is more expensive (and less reliable) compared to Sweden. Sweden happens to have some of the cheapest electricity in the world partly thanks the hydropower generated by the many rivers in the north. But by seeing that number crawl to zero you know that everyday you consume. The water heater eating up most of it (when it's on), fridge and freezer contributing to a steady decline, and then a number of appliances such as lights, computers and phones that need frequent charging. It doesn't give you a nice things-by-thing breakdown, but hey, awareness is the first step!