A few words on DRBD and user space - kernel interfaces

Why not using protocol buffers ( http://code.google.com/apis/protocolbuffers/docs/overview... ) for all complex extensible APIs between kernel and userspace? .proto files could be shipped together with kernel headers, so userspace programs could uniformly use them for talking to kernel. strace-like programs could dynamically decode proto messages using the corresponding .proto files.

Here is a list of protobuf features.
- protobuf messages are designed to be extensible and backwards-compatible;
- protobuf encoding is architecture-independent;
- protobuf encoding is space-efficient;
- protobuf encoding is quite simple ( http://code.google.com/apis/protocolbuffers/docs/overview... ), so it is easy to write cpu-efficient codecs with small footprint in arbitrary language;
- protobuf messages can contain another protobuf messages;
- .proto files can include another .proto files;
- encoded protobuf messages can be easily stored to files (space-efficient binary logs), which then can be easily decoded into human-readable text by universal decoders using corresponding .proto definitions;
- according to the http://code.google.com/p/protobuf/ , "Google uses Protocol Buffers for almost all of its internal RPC protocols and file formats" ;)