||Side 1: This side of the cassette contains just one band which forms part of unit 1. The course team chairman, Professor Darrel Ince, discusses the phases involved in the development and production of the RB211 aero engine at Rolls Royce in Derby with Gordon Waddington, who is one of their chief design engineers. Students are invited to identify the different phases of the project in the light of their (limited) experience on M355, and to note both the similarities with and differences from the project stages in Software Engineering. In particular they are asked to look for the way in which the specification was developed, for the uses of mathematical and computer packages, for the manner in which prototype engines are built and tested, and for the arrangements made for both maintenance of the final engine and for any future developments. The first section of the tape contains a brief history of the RB211 engine; this was initially developed to power the Boeing 747 Jumbo Jet in the 1970s. Next follows a discussion of the way the project was controlled. The first stage of development, the "Concept stage", took several years to complete before Rolls Royce went on to the next stage, the construction of the "Business case". Construction of the "Business case" meant both the identification of market requirements and a start on the design of the engine itself. This design process specified some of the technical requirements of the engine. The outcome of the initial design stage was a specification of some technical requirements of the engine. The results of this stage, the "Project study", was then forwarded to the Executive Board for their approval. On acceptance of the Project study the next phase was the "ITP" or Intention To Proceed all the detailed engine design drawings were worked out, together with plans for, and costings of, the final manufacture of all the components (things like nuts and bolts), and of the complete engine on the production line. This stage of the project involved the use of computers and mathematical techniques, both for calculating tolerances and so on, and for simulating the operation of components. Engineers from a wide variety of disciplines were involved including manufacturing engineers. Indeed a lot of component manufacture took place at the same time as design, because the lead times involved are tremendously long. A great deal of redesigning and remanufacturing occurred at this time. Finally some prototype engines were made and tested, first on the ground, then at simulated altitudes, and finally in the air. In addition, before the engine could be sold, it also had to pass a stringent series of acceptance tests laid down by the Civil Aviation Authority. Finally the engine was tested with the aeroplane which it was intended to power and, lastly, approved by the aviation authority for the country of registration. In the last part of this tape section Barrel Ince and Gordon Waddington discuss some of the inherent problems when the original design had to be modified to reflect new developments in technology, market pressures, and different aircraft body designs. Side 2: This side of the cassette contains just one band which forms a part of Unit 4. Professor Darrel Ince discusses how programme development can use the ideas of loop invariants, pre and post conditions. At intervals, students have to stop the tape and do some work, using the tape frames which are in the Unit and which are to be used in conjunction with this band. The first problem to be studied is that of determining the first occurrence of a given integer in an array. Darrel Ince uses this to develop the following seven steps to be followed when developing a program to tackle the problem: (i) Defining pre and post conditions, using predicate calculus. (ii) Identifying any loops. (iii) Identifying the loop invariants for each loop. (iv) Developing the guard of each loop. (v) Developing statements that initialise the loops. (v±) Developing statements for the body of the loops. (vii) Checking that the loops will terminate. Having gone through all the outcomes for the given problem, the band goes on to use these same seven steps in dealing with a more complicated problem, that of counting the number of even integers in a given array. As before students have to answer questions, and thereby develop several of the steps for themselves, by turning the tape off and using the frames in the Unit.