This thesis describes a new method of constructing a real-time
interactive software system for a minicomputer to enable the
interactive facilities to be extended and improved in a multitasking
environment which supports structured programming
concepts. A memory management technique called Software Virtual
Memory Management, which is implemented entirely in software, is
used to extend the concept of hardware virtual memory management.
This extension unifies the concepts of memory space allocation
and control and of file system management, resulting in a system
which is simple and safe for the application oriented user. The
memory management structures are also used to provide exceptional
protection facilities. A number of users can work interactively,
using a high-level structured language in a multi-tasking environ=ment, with very secure access to shared data bases. A system is
described which illustrates these concepts. This system is
implemented using an interpreter and significant improvements in
the performance of interpretive systems are shown to be possible
using the structures presented. The system has been implemented
on a Varian minicomputer as well as on a microprogrammable micro=
processor. The virtual memory technique has been shown to work
with a variety of bulk storage devices and should be particularly
suitable for use with recent bulk storage developments such as
bubble memory and charge coupled devices. A detailed comparison
of the performance of the system vis-a-vis that of a FORTRAN based
system executing in-line code with swapping has been performed by
means of a process control Case study. These measurements show that
an interpretive system using this new memory management technique can
have a performance which is comparable to or better than a compiler.
oriented system. / Thesis (Ph.D.)-University of Natal, 1978.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:ukzn/oai:http://researchspace.ukzn.ac.za:10413/6258 |
| Date | January 1978 |
| Creators | Heher, Anthony Douglas. |
| Contributors | Nattrass, H. L. |
| Source Sets | South African National ETD Portal |
| Language | en_ZA |
| Detected Language | English |
| Type | Thesis |
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