Monday, April 13, 2015

Gone Hacking

This week we have Hack Week at SUSE. The whole engineering team works on projects of their choice during this week. Everybody is free to innovate, to learn, and to collaborate with others.

We are doing it for the twelfth time. Sometimes magic happens, sometimes people learn a new skill, sometimes we become smarter because we know one more way how not to do things. We always have lots of interesting projects. Hack Week is an amazing experience. You actually can join.

I'm part of the organization team again, providing the environment where our engineers can be creative, productive, have fun, and learn. If I find some time to work on my own project I will tackle the one I worked on last Hack Week already, Project MySelf.

I'm gone hacking now. See you next week.

Friday, April 10, 2015

55.555 downloads of ownCloud in a box

Recently I passed a magic number with my ownCloud in a box appliance. It hit the five fives, 55.555 total downloads, on SUSE Studio. It is the most popular download there. I would never have imagined that so many people would be interested in it and use it when I started with this. Amazing.

When Frank started to discuss the idea of ownCloud and announced it at Camp KDE five years ago (another five, hooray) I was immediately intrigued. The idea of giving people control about their data in the cloud was powerful. Over the years it actually has gained even more power and relevance, as not only the cloud has become ubiquitous but also the threats to abuse it.

With SUSE Studio it became so easy to build easily deployable images for a broad variety of targets, such as a live CD, a VMware image, or an installation disk for a physical machine, that I just had to do it. It follows along the philosophy of ownCloud to make it as easy as possible to run it, so many people can do it on their own. ownCloud in a box is an easy way to try it and get started.

I'm looking forward to the next fives, whatever they will be. ownCloud has great success, and its development is coming along nicely, but I would still like to see some more things.

From a technical point of view, client-side encryption would allow to use a hosted ownCloud without having to trust who is hosting the server. That would extend the benefit of controlling your data in the cloud to a whole new group of people, who can't or don't want to run their own server. There is some work going on in this area. Let's see where this goes.

From a community point of view it would be great, if the contributor agreement would be a bit more fair towards contributors. It's quite asymmetric. You broadly give all rights on contributions to ownCloud Inc. but only get back what you would get anyway by publishing your code under the AGPL. I understand that this enables the ownCloud Inc. business model, and that a successful company is good for the community. I also have no doubt that the company is operating with the best intentions for the community. But if there needs to be a formal agreement, it would be nice if it would better take into account the interests of both sides. I'm sure there would be ways how to do that without jeopardizing the business model.

In general I'm very impressed with how far ownCloud has come, and I'm happy that I could contribute my little part in it.

Saturday, April 4, 2015

The Space-Time Continuum of KDE's Activities

This is not about KDE e.V.'s new time travel program. This is about Plasma and its concept of Activities. They have been a topic of hot debates. Some people love them, some don't care. Björn called for finding a new metaphor which better fits the mental model of the user, so that Plasma's activities can appeal to a larger group of people. Here are my thoughts.

Orthogonal or hierarchical?

The premise of Björn's quest for a new metaphor is that the current one doesn't fit the mental model of the people using activities, especially how activities are related to virtual desktops. He sees activities not as an orthogonal concept to virtual desktops, but as an hierarchical one.

Matching the mental model of the user is crucial, because this defines how natural and easy it is to use them. You can learn abstract concepts and be trained in creating new mental models or in using rules to work with concepts without having a good deeper understanding. But this needs time and effort, which especially casual users are rightfully not willing to spend. And it's not fun.

Orthogonal concepts are independent of each other, they live in different dimensions, you can use one without affecting the other. Hierarchical concepts use the same dimension, but there is an order, one concept is above the other, such as one providing a grouping for another.

You could see activities as independent of virtual desktops, and that's how they are implemented. But there is one issue with that. The presentation we use addresses the same mental model, that of areas arranged in space.

That makes it hard for the user to know where things are. Does the screen present an activity or a desktop? Do I have to change the activity to go to my email client or do I have to switch desktops? When I go to the left or right, do I change activities or desktops? You can learn the concept of activities to be able to answer these questions, but if you use the same mental model for activities and desktops it can appear confusing and inconsistent.

I think there are two ways to address this issue. One is to clearly express that the concepts are orthogonal in the user interface and the naming. The other is to make activities and virtual desktops fit into the same mental model by clearly separating their responsibilities, and eliminate the metaphors which use the same mental model for different parts of functionality.


One powerful way of expressing the orthogonality of activities and virtual desktops would be to represent virtual desktops in space and activities in time. These are two different dimensions, and it actually would go quite naturally with what the two concepts represent.

Virtual desktops are different segments of the space of your desktop. They are usually arranged in a plane and there is a relation of left/right and above/below. Desktop effects support this model by providing spacial transitions when switching desktops.

Activities are less about where you do something but about when you do it. They represent projects or different times of your usage of a computer. You program as part of your job in your IDE in the morning, browse the web and watch YouTube movies in the evening, and once everybody else is sleeping you play a game. You use different applications at different times, need different configurations of your desktop, and there is a relation of before/after between these.

To express this in the UI the activity switcher and configuration should not use concepts of space which overlap with how virtual desktops are presented. The closest idea I have seen is the activity switcher in Plasma Active. This uses a different and specific mechanism to switch activities. It even vaguely resembles a clock with its circular movement of activities when browsing through available activities, expressing the concept of time.

Screenshot from contourproject
When going with this mental model and the corresponding metaphors, suitable names for activities and virtual desktops could be "times" and "spaces".


Following the idea of a hierarchical relationship of activities and virtual desktops we could represent them using the same dimension, but express activities in groups of virtual desktops.

Here is a mockup illustrating this idea:

Activities would control how groups of virtual desktops would behave. They would be used to define what wallpaper and which desktop widgets to show, what applications to start or stop, what settings for notifications or power saving to use, etc. All this would be tied to on what virtual desktop the user is. But there wouldn't be two different ways how to switch between desktops and activities, but there would only be one. Activities would implicitly be switched by switching between virtual desktops.

So when you are at work you would be on the left side of your desktop with your corporate wallpaper, running IDE, web browser, what you need for work. The right side of your desktop with the games would be shut off. For a presentation you would go to the desktop which switches off notifications and power saving. Email would be there as a shared resource all the time. In your free time you would be on the right of your desktop, with nude pictures of your cat as background, running inappropriate videos in your web browser, and switching off everything else than your games for maximum frame rates. Or something like that...

In some way activities would be a subset of virtual desktops and in some other way they would be a configuration for a virtual desktop. This follows along the lines of the "Different widgets for each desktop" configuration option, where each virtual desktop more or less gets its own activity.

The hierarchy would not strictly be activities above and desktops below, but there would be two concepts, the group above the desktop, and the configuration below the desktop.

This would need a few changes in representation of activities and virtual desktops, but it could better match the mental models of users, because concepts are clearly separated and existing understanding of controls can be used.

When going with this mental model and the corresponding metaphors, suitable names for activities could be "desktop groups" and "desktop configuration", and virtual desktops would just remain "desktops".


Naming is important, but even more important is expressing concepts clearly and unambiguously. In the user interface behavior and visual representation trumps names. That said, for talking about the concepts, especially in code and documentation, good names are essential.

To me seeing activities as configuration of groups of desktops is most natural. That matches my mental model.

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