Sunday, March 13, 2016

Software selection - choice or constraint?

In Tribblix, software is preferentially managed using overlays rather than packages.

Overlays comprise a group of packages bundled together to supply a given software need - the question should be "what do you want to do?", and packages (and packaging) are merely an implementation artifact in providing the answer to that question.

Part of the idea was that, not only would the overlays match a user's mental model of what they want to install, but that there would be many fewer overlays than packages, and so it's much easier for the human brain to track that smaller number of items.

Now, it's true that there are fewer overlays than available packages. As of right now, there are 91 overlays and 1237 packages available for Tribblix. So that's better than an order of magnitude reduction in the number of things, and an enormous reduction in the possible combinations of items. However, it's no longer small in the absolute sense.

(Ideally, small for me means that it can be all seen on screen at once. If you have to page the screen to see all the information, your brain is also paging stuff in and out.)

So I've been toying with the idea of defining a more constrained set of overlays. Maybe along the lines of a desktop and server split, with small, large, and developer instances of each.

This would certainly help dramatically in that it would lead to significant simplification. However, after trying this out I'm unconvinced. The key point is that genuine needs are rather more complicated than can be addressed by half a dozen neat pigeonholes. (Past experience with the install metaclusters in Solaris 10 was also that they were essentially of no use to any particular user, they always needed to be customised.)

By removing choice, you're seriously constraining what users can do with the system. Worse, by crippling overlays you force users back into managing packages which is one of the things I was trying to avoid in the first place.

So, I'm abandoning the idea of removing choice, and the number of overlays is going to increase as more applications are added. Which means that I'm going to have to think a lot harder about the UX aspect of overlay management.

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