Form U126-0394 CUT-TIME.TXT
Ada Information Clearinghouse, 1-800-AdaIC-11 (232-4211), 703/685-1477
The Bernische Kraftwerke - Leitsystem Energieverkehr is the electricity supplier for the region surrounding the town of Berne, Switzerland. The production and consumption of electricity is monitored at a large number of switching stations. This monitoring information is transferred every 15 minutes to the central database. The information is then available over a Wide Area Network (WAN) for detailed on-line and batch analysis.
The LSE project, although by no means a large software system, contains many features familiar to professional software developers:
The hardware configuration consists of a central cluster of VAX 4000 computers which access the database directly, and a collection of (VAX) workstations that communicate over the WAN with the "server" processes in order to manipulate the data as required. The operating system on all machines is VMS, and all programs are written in Ada (DEC Ada). The source files total about 80,000 lines of code.
The reasons for choosing Ada as the programming language for this particular project can be simply stated. Ada has been in use in Paranor since 1985, and we are happy and comfortable using it. There has been no discussion at all as to what programming language will be used at Panor: It is automatically Ada. In this particular project there was also no resistance from the customer (as is occasionally the case).
The development team consisted of four designer/programmers working reasonably independently. The main interfacing being done physically via the database and technically via common type definitions (Ada packages).
This project saw the introduction of a development environment (directory structure, command scripts) that has since been used and extended in later projects. The DEC-Ada system of chains of program libraries is used in order to allow parts of the application (subsystems) to be developed 'privately' without disturbing the other developers excessively.
We also developed a system of developing VMS sharable images written in Ada, which, although it cuts out some of the checking done by the Ada-System, is still verifiable using 'home-built' support procedures and offers the two large advantages of cutting down link time in development and easing maintenance of the production system.
For those not so familiar with Ada, here are the main plus points:
The original system, replaced by this project, which ran on PDP 11/44, RSX 11-M, FORTRAN, required 9 minutes to process the data each 15 minutes. The new system takes 2.5 seconds!
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