When decision tables are introduced as a method of expressing logic, many people find the term intimidating and take a mental step back. In reality, we use calendars and time tables frequently with no trouble and spread sheets can now be found in every office and in many other walks of life.
Decision tables are an efficient way of expressing logic and, because of their structure, can be checked easily to ensure that all possible combinations of outcomes have been identified. This helps the programmer cater for the unexpected.
Flowcharting deals well enough with expected values but not so well when defining the procedures to be followed when error values do not match results explicitly catered for.
The earliest use of decision tables in computing was in the late sixties when "to make life easy", a report writer was created that accepted parameters to produce variants of a single, simple report.
This led to a product called TABN that produced reports for ICL 1900 series computers (TABulator for the Nineteen hundreds!). The other common commercial computer in the seventies was the IBM 360 series and hence TAB360 was born. These were in turn followed by HTAB and UNITAB for other computers.
By the mid-seventies, the generic term FILETAB was being used to cover all these versions and their common concepts. The ideas of decision table programming were also growing in strength and the concepts were taken through to a new version of FILETAB called FTL6 via an intermediate version called DTPL. FTL6 became a commercial programming language in its own right, being able to do much more than the simple reports of the early days.
There were also moves to make the simple reporting more available to the end user by creating a tool, USERTAB. It took words that the end user would recognise as English and generated both the FILETAB code and report program automatically.
By the eighties, DEC (Digital Equipment Corporation) was providing PDP computers in large numbers for commercial use and RPL and RQL were available as the FILETAB and USERTAB versions for the PDP hardware. Subsequently DEC released the VAX and Alpha ranges of computers and the programming tools evolved into expertGenius and the Genius solution while the end user reporting tools became easyGenius and Genius User.
Since those early days, substantial development effort has been invested in creating the effective commercial programming tool set we have today - the Genius Application Suite.
This development effort has progressed on three fronts:
The core programming language has been extended to provide a comprehensive tool, giving the commercial programmer everything needed to write cost-effective programs for the twenty-first century. This has been achieved by evolution rather than revolution so that legacy programs still work, albeit without access to the full functionality now available.
The application suite has been enhanced to provide both programmer and end user with tools that make data access easier and achieve results more quickly and efficiently. Specific components in the Genius Application Suite are designed to tackle specific tasks that major enterprises have to address.
Significant effort has applied to portability, both in terms of data structure independence as well as the facility to use the same (or only slightly modified) code on different platforms.
Organisations need to maximise return on investment by making effective use of legacy systems that are still functioning reliably. They must be able to extract and route data to a variety of applications on a range of platforms, thereby extending the life of their software and hardware investment.
Eventually, when a legacy system must be retired, most organisations need to ease the process of porting data to a new platform and ideally reuse existing code within the new application.
In all these areas, the Genius Application Suite can help. Why not contact us for further information?