[Rusky]

The authors went on to implement a couple systems that handle that problem rather nicely. Applications (really, the libraries they use) do know about disk sectors, but the kernel's disk driver sorts their requests to optimizes seeks and exposes which sectors are loaded, to allow a kind of cooperative disk cache.

Even more interesting, they let applications share file systems by taking a bytecode-based representation of FS metadata from userspace, and using that to enforce correct usage of the actual disk blocks. This lets applications control where on the disk to allocate, when to read which blocks, etc. without losing any of the security and cooperation of a typical file system.