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Comment by kyrra | Hacker News Reader

Googler, opinions are my own.

This was my understanding as well. The original Drive was built effectively as a directed graph (with cycles allowed). Any file or folder could be stored in multiple locations. And permissions were at a per-file basis, so 2 people viewing the same folder may see different sets of files.

And permissions were definitely a hard part of it, as if you applied new permissions to a folder and all children, it had to walk the entire graph to update the permissions.

This is the advantage of the Team Drive style structure that the Drive team put out. It follows the classic filesystem design of a tree, which allows for easier permissions modeling, among other things. It's also why all "hard links" are now becoming shortcuts / Soft-links.

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Forgive my ignorance (and there's a lot of it), but navigating a graph and setting permissions doesn't seem like a terribly difficult problem, especially for Google - the king of graphs, in a word. I would think maybe the issue has to do with how permissions of a file/folder apply to different users, but then isn't that just exactly the raison d'etre of permission systems?

This isn't an area I'm qualified to have a technical opinion on but if you'd care to elaborate I'd be interested to learn more.

Googler opinions are my own. I've never worked on Drive.

It's not hard, but expensive.

If you have a file system where it is a proper tree in any given node within that tree only has One parent, and walking up all the parents you always only have one parent up to the root node, you gain some useful properties from that. You can build a permission model where you just have to check the permissions of all of your parents to see if someone has access to a given file deep within the system. This means that if you Grant Reed access on any node within that line of parents, all children implicitly get access.

Now imagine a directed graph, and you set permission on a node and you want to say all connected nodes also should get this permission. You could definitely walk all the nodes and apply that permission, but now you have to write said permission to every node, rather than being able to set it on a parent and let all children inherit it. Even if you know all of your parents, then all of those nodes have multiple parents. And you can have cycles. Checking parents for permissions becomes way more complicated for users to understand, which is why Drive likely didn't do this.

Can you explain why team drives (now called shared drives) have a limit of 400.000 files while there are no limits and unlimited sharing for files in "my drive"?

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