LPA Application Brief #3

CompanyThe Chessington Computer Centre
ProductWIN-PROLOG, Flex

"Ajax was developed partly in response to potential problems, but also as a way to free people to do more useful work"

Chessington Computer Centre is using WIN-PROLOG to simplify its payroll business. The Centre provides payroll services to around 70 large civil service customers. Mike Cook, technical manager, says this means processing around 170,000 salaries every month. Cook says he can support nearly all changes that customers want, with a minimum of amendments to the system.

The program that does all the number crunching is an extensive suite of batch jobs tied together by ICL's System Control Language (SCL) on an ICL S39 L80 VME mainframe. It can be installed at the customer's premises, or Chessington can provide a bureau service. In this instance, all the processing is carried out on the Centre's S39 L80, and the customer links into the mainframe from their own site to send and access their data, as well as collect the payroll.

A major problem with this kind of system, says Cook, is dealing with amendments to input data, or requests for one-off jobs. Because certain jobs have a high interdependence, slotting in a new job has to be done carefully. Traditionally, schedules had to be worked out some time in advance and distributed to those involved with system, including customers, and staff.

Because of the way the system had evolved, setting up the job runs was a delicate task carried out by a small number of people who could write the necessary SCL scripts. The situation had obvious problems, not only was the expertise that kept the system chugging along in the control of only a handful of people, but it had become clumsy. The Automated Job Assembly eXpert (Ajax) was developed partly in response to potential problems, but also as a way to free people to do more useful work.

Ajax is a classic intelligent front-end interface to a complex back-end engine. It has two main functions: to generate intelligent schedules based on the captured knowledge; and to run the jobs in the correct order with the right parameters. The first task is achieved through a rulebase written in LPA's Flex. A calendar of events such as bank holidays, feeds information to the KBS, which can then use its rules to reason about which jobs for which customers should be run in what order.

Frequent changes mean the schedule it generates cannot be written in stone. The operator can amend it by searching through a possible list of jobs and adding them to the existing schedule. And jobs can be re-ordered, or removed from the schedule. Ajax can then submit the job schedule to the mainframe from the local 386 PC. It then monitors the progress and prints out documents needed for administration.

The company's success with Ajax has led it to start work on another application. It is using LPA's Prolog and Flex to schedule office activities and workflow systems.

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