Give and What scheduling problem could arise here? [2 marks] (ii) How could this problem be overcome? [2 marks] (d) The designer also wishes the real-time system to use demand paged virtual memory for efficiency. What problems could arise here, and how could they be overcome? [6 marks] 6 Numerical Analysis I (a) For Single Precision in the IEEE binary floating-point standard (IEEE 754) the precision is defined as 24, and the exponent requires 8 bits of storage. With reference to IEEE Single Precision, explain the terms exponent, significand, precision, sign bit, normalised number, denormal number.

on of a Turing machine that is specified by a quintuplet description. [(c) Define the configuration of a Turing machine at step t, and establish equations that specify the configuration of a k-symbol Turing machine at step (t + 1) in terms of the configuration at the previous step t. [6 marks] (d) Explain how you would use your equations to simulate a specific Turing machine by a register machine whose program encodes the quintuplet description. To what extent does this support Turing's Thesis? [Explicit program for a register machine is not required.] [8 marks] 8 Computer Graphics and Image Processing Describe an algorithm for performing scan conversion of a set of 3D polygons, including details of clipping, projection, and the underlying 2D polygon scan conversion algorithm. You may assume that you are given the colour of each polygon and that no lighting calculations are required. Please state any additional assumptions that you need to make. Ray tracing is not an acceptable answer to this question.

(b) Give two different ways of implementing residual information protection in an operating system and explain the threat addressed by each. [5 marks] (c) Consider the standard POSIX file-system access control mechanism: (i) Under which conditions can files and subdirectories be removed from a parent directory? [2 marks] (ii) Many Unix variants implement an extension known as the "sticky bit". What is its function? [2 marks] (iii) On a POSIX system that lacks support for the "sticky bit", how could you achieve an equivalent effect? [2 marks] (d) VerySafe Ltd offer two vaults with electronic locks. They open only after the correct decimal code has been entered.

(b) Consider the use of a monad for input-output. For the purposes of this question, take the IO monad as including two operations readint and writeint which respectively read integers from stdin and write integers to stdout. Give the types of these operators. . When so applied it should give a value in the IO monad which corresponds to ML code that runs add1 twice and returns the difference between the values read.

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. In each case, would you discard this feature if your employer let you, or insist on retaining it (even covertly) should your employer not value it? Explain your reasons. (a) Dividing a project into short development episodes or sprints. (b) Project progress visualisation tools such as PERT and GANTT charts. (c) Automated regression testing tools. (d) Source code management tools.