I work at Boeing (150,000 employees), and one thing they’re absolutely crazy about is trees, both in employee structure (management trees are *very* narrow), and programs (they like to put *everything* in big hierarchical databases). It’s insane how tree-crazy they are here. The complexity is incredible; to generalize (slightly), nobody has any taste or sense of simplicity, so everything grows very quickly in complexity beyond the ability of any mere mortals to understand it.

They even have a way to make a Gantt chart into a tree. Yeah, I know.

My previous job was at a university. They barely even used the filesystem hierarchy: almost everything was two levels deep in the folder structure. It was very manageable. If I had to pick one data structure to describe that experience, it would have to be the list (either linked, or array). Dictionaries were a close second, just to store some key,value-style metadata about the lists.

I’m now looking for another list/dict job.

Ahaha so true. When we were at WebObjects training years ago the group developed a phrase that we would slip in at every opportunity - “The NSDictionary is the computer!” - a (bizarre) reference to the Sun jingle of the day.

All this means is that unfortunately the interviewers on your friend’s loop didn’t get together beforehand and make sure their questions were sufficiently diverse.

If you want to accuse anyone of being over-fond of trees, how about the C++ STL authors? IIRC that had tree-based structures exclusively for years - before hash_map was added to the standard. I think that was due to comparison being considered a more basic operation than producing a hash code.

What do I think this means about Microsoft vs. Apple? It could be nothing more than a difference in the respective job positions… or - and I suppose this is possible - it could indicate that Apple fosters an object oriented approach to systems building in contrast to Microsoft, which prefers a low-level approach that is driven more by computer science theory than by software engineering best practices.

If I remember, a lot of MIT people back in the 70s broke the computer world into the Lisp and non-Lisp data typers. The Lisp folk took a casual attitude towards data structures - just shove them in a list, put them on a plist, stash them in a cache. If it gets slow or confusing, add some tags and a hash algorithm. Most non-Lisp folk were appalled at this. They wanted to see the data structure design up front, the data relationship dictionary, complete and comprehensive, even before any coding started.

You get a similar dichotomy today. The Microsoft people want to have a clue as to what is going on before they start working, so they build a tree structured model. They want to know what is important and what is not. The Apple people don’t care about having a clue, as long as they get something useful and usable. They know that what they think is important may not be important to their customers.

This is probably an old Apple corporate thing. The Apple II was basically a platform for running VisiCalc on, the proverbial tail wagging the dog. Excel and MarinerCalc aren’t the big reasons for buying an Apple these days. You’re more likely to want an Apple for Mosaic or SoundJam, or their successors. Apple figures that most of its users are smart, and that they’ll figure out what to do with the box, if the box lets them do it.

Microsoft, in contrast, took over the old IBM operating system monopoly, and the old OS\360 business model. Businesses are hierarchies with the boss at the top. The software has to reflect this. Everyone, and every piece of software and data, has to know its place. You can’t just have people running around making things and selling them. As long as users can get their assigned jobs done, the box and its software are great.

I suppose we should consider this progress though. Microsoft is tree oriented. The old IBM was array oriented. One step at a time.