Mental Models from my Diary

Just over viewing my Diary since September 2025 to March 2026 - I extracted next crucial mental models. These mental models are sharped during hard battles in local communities.

Kernel <= SysCalls => UserSpace;

Kernel(TCP) <= Socket => UserSpace(TLS)

Kernel(OSI[1..4])<=Socket=> UserSpace(OSL[5..7])

In common all these models tell about one concept Interface-Contract, that is implemented and kept for decades in UNIX TCP/IP stack. Where the socket interface is a contract between Kernel internal implementation and UserSpace internal implementation. As It is possible to observe these models [Internal]<=Interface=>[WorkingGround] are very similar, and could be found in different areas of Networks and Web Development.

(HTTP.1/HTTP.2/QUIC)<==[request/response interface]==>(Ruby/PHP/Perl/Python frameworks)

Starting from OS and keeping exploring up to App implementation it is required to do the same thing - define Interface-Contracts that would be stable for a long time.