The grandfather of all text-based adventure games is Colossal Cave Adventure, which also went by the names Adventure and ADVENT (on early systems with file name limits). Adventure was created by Will Crowther and Don Woods in 1975-1977 and originally written in FORTRAN (a third-generation computer language) for PDP minicomputers. It has been ported to many other systems and rewritten in several other computer languages. (b) What statistical properties of memory access do caches exploit to deliver

improved performance? [4 marks]

(c) What impact will an operating-system-managed context switch have on cache

hit rate? Justify your answer. [4 marks]

(d) Modern desktop and server processors support simultaneous multithreading

(also called hyperthreading). When will there be a performance benefit in

scheduling two non-interactive applications on the same hyperthreaded processor

core so that they run in parallel rather than running sequentially, one job one

after the other? [4 marks] (ii) A colleague suggests replacing the system above with one that provides 80 GB/s memory read bandwidth and main memory access latency of 30 ns. Explain whether you should accept the replacement or not, and why. [4 marks] (c) A creative engineer suggests structuring the TLB so that not all the bits of the presented address need match to result in a hit. Suggest how this might be achieved, and what might be the costs and benefits of doing so. [6 marks] (a) (i) In a Hopfield neural network configured as an associative memory, with

all of its weights trained and fixed, what three possible behaviours may

occur over time in configuration space as the net continues to iterate in

response to a given input? [3 marks]

(ii) How many stable content-addressable memories would you expect a fully

connected Hopfield network consisting of 100 neurons to be capable of

storing? [1 mark]

(iii) What property of those memory patterns would make it most probable

that you could successfully train the network to store the maximum

number, and why? [3 marks]

When they meet after the Examination, the Examiners are astonished to discover

that, using a threshold of 20 marks, considerably fewer than one-third of the

candidates gain Firsts.

(a) Assuming that dice throws are independent, what is the probability that a

candidate obtains 20 or more marks overall? [12 marks] In a proposed, next-generation banking system a number of transactions are to be scheduled to run concurrently: Debit (D) transactions to make payments from customer accounts to a credit card company. Interest (I) transactions to add daily interest to customer account balances. (iii) Explain how a formal schema can assist both the application database designer and a database application programmer. What if any are the disadvantages of adopting a mathematical description of database structure? [5 marks] (b) In 1976 Peter Chen introduced the Entity Relationship (E-R) Model to support a more natural description of real world data. (i) Describe the basic elements of the Model, and explain some of the choices available to the database designer. [4 marks]