Data base optimisation for an I.C. design layout package on the VAX.
The performance of an interactive graphics/computer aided design system, such as the IC layout and rule checking package implemented as part of the schematic drawing application on the Gerber Systems Technology IDS-80, is very closely related to the performance of the system's data base. This is due to the fact that most editing functions on an interactive graphics/CAD system are data base intensive functions and the data base and its management routines form one of the major building blocks of a CAD system. It can therefore be said that the performance of a CAD system is directly dependent on the data base access time and the efficiency of the managing routines. The primary objective of this project was to enhance the performance of the IC layout and rule checking package. This was done by improving the performance of the data base of the system. This was achieved by following two mutually supportive paths. The first was the transportation of the software to a new host machine which had a 32-bit processor and virtual memory capabilities. The second was to try and improve the performance of the transported data base by utilising sophisticated data base structures and memory management·techniques facilitated by the larger available memory of the new host to optimise the data base operations. The effectiveness of the two paths in achieving their respective goals was evaluated using evaluation programs which simulated characteristic data base activities.This thesis documents the above process, as well as expounds on some of the background related theory which was instrumental in the progress of the project and the drawing of the final conclusions.