A wearable computer

The HoloLens is a wearable computer. That is something that we have to keep in mind all the time when we write software--people will walk around with the device on their head, and we need to take that into account. It is not only wearable, it is also head mounted.

The device works without any cables attached to it, and the six built-in (non-replaceable unfortunately) batteries make sure that you can use it for 3-4 hours. They designed it like this because the device is meant to be worn on the head and be walked around with. I know, I just said that but this is so fundamentally different from what you are used to that I cannot stress this enough. If you have developed applications for mobile platforms, such as mobile phones or tablets, you might argue those are wearable as well. Well, technically they are, but those devices generally do not interact with their environment. They are location-agnostic. They might know where they are, but they do not really care, but the HoloLens does and so your software should care about the location as well.