Yes sure, the "successor" system that was eventually implemented to redundantly host BLOBs of all kinds used a very similar scheme - it's a well-known and effec

Yes sure, the "successor" system that was eventually implemented to redundantly host BLOBs of all kinds used a very similar scheme - it's a well-known and effective technique for, e.g., on-disk caching in popular HTTP server implementations. The problem that kept us from doing something like this with out pile of 1.2M images was that there were several different codebases (and even a hand full of remote sites which had code that we knew relied on this assumption, and that we could not directly affect or change) that tied into this flat directory full of image junk in various ways (via the local filesystem, NFS, over HTTP, and I think even FTP was in use for a while after I had originally joined), which made it very hard to push through any breaking changes, no matter how architecturally sound they would have been.