I was having a conversation with a (now former) coworker (a while ago) about the future of shared file systems, unstructured organization and management, and access control. What follows are a collection of notes and thoughts on the subject that have stuck with me.

Let's start with some general assumptions, premises, ideas:

  • File system hierarchies are dead or dying. To have a useful file system hierarchy the following qualities are essential:

  • Every piece of data needs to belong in one location and only one location.

  • Every container (e.g. directory or folder) needs to hold at least two objects.

  • Hierarchy depth ought to be minimized. Every system can use two levels. After the second level, each additional level should only be added a very large number of additional objects are added to the system. If you have 3 functional levels and less than 1000 objects, you might be in trouble.

    As you might imagine, this is very difficult to achieve, and the difficulty is compounded by huge amounts of legacy systems, and the fact that "good enough is good enough," particularly given that file organization is secondary to most people's core work.

    While there are right ways to build hierarchical structure for file system data, less structure is better than more structure, and I think that groups will tend toward less over time.

  • Access control is a lost cause. Legacy data and legacy practices will keep complex ACL-based systems for access control in place for a long time, but I think it's pretty clear that for any sort of complex system, access control isn't an effective paradigm. In some ways, access control is the last really good use of file system hierarchies. Which is to say, by now the main use of strong containers (as opposed to tags) is access control.

    I don't think that "enterprise content management"-style tools are there, yet. I suspect that the eventual solution to "how do I control access to content" will either: be based on a an cryptography key system which will control access and file integrity, or there will be a class of application, a la ECMS, with some sort of more advanced abstracted file system interface that's actually use-able.

I'm betting on encryption.

  • Tagging and search are the ways forward. In many cases, the location of files in hierarchy help determine the contents of those files. If there are no hierarchies then you need something more useful and more flexible to provide this level of insight.

  • Great search is a necessity. Luckily it's also easy. Apache Solr/Lucene, Xapian, and hell Google Search Appliances make great search really easy.

  • Some sort of tagging system. In general, only administrators should be able to create tags, and I think single tag-per object (i.e. categories) versus multiple tags per object should be configurable on a collection-by-collection.

    Tag systems would be great for creating virtualized file system interfaces, obviating the need for user-facing links, and leveraging existing usage patterns and interfaces. It's theoretically possible to hang access control off of tag systems but that's significantly more complicated.

    One of the biggest challenges with tag systems is avoiding recapitulating the problems with hierarchical organization.

The most difficult (and most interesting!) problem in this space is probably the access control problems. The organizational practices will vary a lot and there aren't right and wrong answers. This isn't true in the access control space.

Using public key infrastructure to encrypt data may be an effective access control method. It's hard replicate contemporary access control in encryption schemes. Replicating these schemes may not be desirable either. Here are some ideas:

  • By default all files will be encrypted such that only the creator can read it. All data can then be "world readable," as far as the storage medium and underlying file systems are concerned.

  • The creator can choose to re-encrypt objects such that other users and groups of users can access the data. For organizations this might mean a tightly controlled central certificate authority-based system. For the public internet, this will either mean a lot of duplicated encrypted data, or a lot of key chains.

  • We'll need to give up on using public keys as a method of identity testing and verification. Key signing is cool, but at present it's complex, difficult to administer, and presents a significant barrier to entry. Keys need to be revocable, particularly group keys within organizations.

    For the public internet, a some sort of social capital or network analysis based certification system will probably emerge to supplement for strict-web-of-trust based identity testing.

  • If all data is sufficiently encrypted, VPNs become obsolete, at least as methods for securing file repositories. Network security is less of a concern when content is actually secure. Encryption overhead, for processing isn't a serious concern on contemporary hardware.