Give two different ways of implementing residual information protection in an operating system

h. [5 marks] (c) Consider the standGive two different ways of implementing residual information protection in an operating system and explain the threat addressed by each POSIX file-system access control mechanism: (i) [4 marks] (d) State what happens when attempting to compile and execute the following Java fragment (explaining the origin of any error messages or exceptions which might arise). Object n = new Integer(42), o = new String(“Whoops”); Object [] v; Integer [] w = new Integer[10]; v = w; v[4] = n; v[5] = o; [4 marks] (e) Consider the Java code: Object n = new Integer(42); ArrayList v1; ArrayList v2; ArrayList w = new ArrayList<>(10); Explain any differences in behaviour between assignments v1 = w and v2 = w and also between method calls v1.set(4,n) and v2.set(4,n). ote that the children of a branch node are given as a list of trees, and that only the leaf nodes carry labels. datatype ‘a vtree = Lf of ‘a | Br of (‘a vtree) list; (i) Write function flat t that converts a given tree t of this type to a list of the labels (without eliminating duplicates).he retina is often regarded as an image capture device; but it has about 100 million input sensors (photoreceptors) yet only 1 million output fibres (optic nerve axons). What are some implications of this 100-to-1 ratio of input channels to output channels? [4 marks] (d) Provide some quantitative evidence and arguments supporting the proposition that: “Connectivity is the basic computational principle in the brain”. [4 marks] 8 Computer Systems Modelling (a) What criteria would you consider when selecting between a model based on queueing theory and one based on simulation? When might you use both approaches? [5 marks] (b) Describe the structure of a discrete event simulator. What is the principal data structure involved? [5 marks] (a) Give one potential advantage and one potential disadvantage of using notify() instead of notifyAll(). [2 marks] (b) Would it have been beneficial to use notify() instead of notifyAll() in your implementation? Justify your answer. What is Last Call Optimisation and why is it beneficial? [3 marks] (f ) Rewrite pos to enable Last Call Optimisation. [2 marks] pos([],[]). pos([H|T],[H|R]) :- H >= 0, pos(T,R). pos([H|T],R) :- H < 0, pos(T,R). 8 CST.2016.3.9 8 Software Engineering Discuss the contribution and the relative value of the following aspects of the modern development environment. Illustrate with examples from your group project, or from experience you gained working for a commercial software developer, or both. Under which conditions can files and subdirectories be removed from a parent directory?