Slide's architecture is a matrix of modules, from high-level services to low-level services and clearly separates functionality around different aspects (structure, security, locking and versioning).
The high-level interfaces are meant to provide a simple, standardized way of manipulating a namespace. Underneath these clean interfaces lie "pluggable" service implementations, which are the low-level services.
There exist tight dependencies between the high-level services because of the need to enforce security, locking and other contraints throughout the offered client API.
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