Consider the function zarg defined below: fun zarg f ([], e) = e | zarg f (x::xs, e) = f(x, zarg f (xs,e)); Show that with the help of this function, it is possible to an expression for the sum of a given list of integers. Then describe what zarg does in general. [5 marks] (c.ii) A polymorphic type of branching trees can be declared as follows. Note 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.i) Write function flat t that converts a given tree t of this type to a list of the labels (without eliminating duplicates). Your function should run in linear time in the size of the tree. [5 marks] Examine this issue from the perspectives of the two information assurance regulation and morals.

(a) Windows carries out static legacy for the entrance control arrangements of NTFS records

furthermore, envelopes.

(I) What does static legacy mean here and how can it contrast from dynamicinheritance? [4 marks]

(ii) Five flag bits (ci,oi,np,io,i) in each NTFS access-control entry (ACE)

manage how it is inherited. Briefly describe the purpose of each bit.

[5 marks]

(iii) User mike gives his folder project the following access-control list:

project

AllowAccess mike: full-access (oi,ci)

AllowAccess alice: read-execute (ci,np)

AllowAccess bob: read-only (oi)

It contains one folder and two text files, none of which have any noninherited access-control entries:

project\doc.txt

project\src

project\src\main.c

For each of these three objects, list all inherited access-control entries,

showing in parentheses the inheritance-control flag bits that are set (using

the same notation as above). [5 marks]

(b) Describe the purpose and four typical functions of a root kit.

Data Structures and Algorithms (a) Describe and justify an algorithm for finding the shortest distance between each pair of vertices in an undirected graph in which each edge has a given positive length. If there is no path between a pair of vertices a very large result should arise. [12 marks] (b) Is it sensible to use your algorithm to discover whether such a graph is connected? Suggest an alternative that would be appropriate for a graph of 1000 vertices and 10,000 edges.

Computer Design (a) What is a pipeline bubble and why might a branch instruction introduce one or more bubbles? [4 marks] (b) Explain, with the aid of an example, how conditional instructions may be used to reduce the number of bubbles in a pipeline. [4 marks] (c) What is the difference between branches, interrupts, software interrupts (initiated by a SWI instruction on the ARM) and exceptions? [8 marks] (d) What is an imprecise exception and why might a processor designer prefer it to a precise exception mechanism?

The FEC has rate R < 1 and given an error rate 0 provides an error rate 1 (which is detected). The ARQ protocol has a window size of W. At what rate can the information be conveyed? The retina is many times viewed as a picture catch gadget; however it has about

100 million info sensors (photoreceptors) yet just 1 million result strands

(optic nerve axons). What are a ramifications of this 100-to-1 proportion of

input channels to yield channels? [4 marks]

(d) Provide some quantitative proof and contentions supporting the suggestion

that: "Availability is the essential computational standard in the cerebrum".

[4 marks]

8 Computer Systems Modeling

(a) What standards would you consider while choosing between a model in light of queueing hypothesis and one in view of reenactment? When could you utilize both

approaches? [5 marks]