(1) What is the effect of reading up and writing down restrictions imposed by the Bell-LaPadula model? And what is the effect of reading down and writing up restrictions imposed by the Biba model?  (2) Choose one of your favourite operating systems (e

(1) What is the effect of reading up and writing down restrictions imposed by the Bell-LaPadula model? And what is the effect of reading down and writing up restrictions imposed by the Biba model? 

(2) Choose one of your favourite operating systems (e.g. Windows, Mac OS, or UNIX) and compare its security policy with the ClarkWilson model. Does its security mechanism satisfy Clark-Wilson axioms? You may take a look at https://www.giac.org/paper/gsec/835/ clark-wilson-security-model/101747 , though I am sure you will have your own opinion.