SOFTWARE EVOLUTION FORMAL METHODS

Software Evolution Formal Methods

Software Evolution Formal Methods

Introduction

In the US, the Denver International aerodrome is often used by the government Aviation Administration (FAA) as a check site for new technologies. Aperennial dread of the air traveler is the luggage handling scheme: lost sacks, delayed sacks, and lowest of all, bags moved to the incorrect airline, and finish up in remote locations. So, the FAA and the Denver enterprises and political leaders decided that the brand new airport would be a magnificent place to showcase new baggage handling technology. The system requirements were duly prepared, the contract awarded, and millions of dollars committed to a network of computer-controlled conveyors that would whisk luggage immediately to its intended destination (DeNeufville le, 1994). But then came the command system. The primary suggestion that something was incorrect appeared when the rest of the aerodrome, and conveyors, were in location, but the programs conceive had scarcely begun. The project became a public burden when it was over 2 years late on consignment (the rest of the airport could not be utilised without it). Finally, the time for primary testing reached: The scheme could not do even the most basic suit cases transport correctly. Patience wore thin. Political and enterprise status were ruined. Finally, the scheme was cancelled and a “semi-automated” (viz., conventional) system was used rather than! From the control engineer's perspective, the most serious consequence of this kind of malfunction is that the public was left with the impression that automation itself was at fault, and not that (as was undoubtedly the case) the task was mis-managed. Dozens of airports round the homeland will now opt for less automated schemes in favor of more automated ones, and command engineers will have less to do.

The Denver aerodrome baggage-handling example shows the public penalties of seen need of automation software dependability. As a whole, only about 30-40% of large software projects that are initiated will run to completion (Brooks, 1995), and this was one that did not. Even though the record in constructing systems—which are highly structured—is likely better than this mean, it still could benefit from considerable enhancement (Place and Kang, 1993—selected references from older literature have also been repeated here). Start-ups of new manufacturing and process plants are often notoriously delayed. And increasingly software development is at the heart of most of the problems. With the rapid decrease in cost, and even more rapid increase in the capabilities of computers over the last decade, the computing hardware components of automation have become less costly, more versatile, and more reliable. So the drive to shift hardware functions into software has accelerated over the last decade. Manufacturing software itself has expanded from isolated, carefully designed PLC logic systems that operate for months without interruption, to PC-based platforms, where even in the absence of an application; the operating systems must be rebooted every few days!

In spite of the expanding grade of dependence of manufacturers on automation software that is expected to be protected ...