In my opinion good abstractions layers should also have a way to peel things back like layers of onion.
Taking the authors example of a TCP network stack you often can't do though since OS won't let you have that low level of access by default without using or writing some custom driver since the OS ends up trying to isolate usee-space completely.
Kinda makes me wish more research has been done on things like exo-kernels where the OS is mainly concerned with security and not the abstraction. All the abstraction runs in user space on such a kernel and you can choose what level is suitable for what your doing. https://en.wikipedia.org/wiki/Exokernel
Taking the authors example of a TCP network stack you often can't do though since OS won't let you have that low level of access by default without using or writing some custom driver since the OS ends up trying to isolate usee-space completely.
Kinda makes me wish more research has been done on things like exo-kernels where the OS is mainly concerned with security and not the abstraction. All the abstraction runs in user space on such a kernel and you can choose what level is suitable for what your doing. https://en.wikipedia.org/wiki/Exokernel