EHLLAPI - The Olde Way to Interact with Screen-Based Applications

EHLLAPI, or the Extended High Level Language Application Programming Interface, was introduced soon after the introduction of the IBM 3270PC

The IBM 3270PC was a special personal computer that integrated a 3270 COAX adapter and a specialized keyboard. The 3270PC eased the transition between a traditional terminal and a Personal Computer for those users looking to merge the functionality of the two.

A Little History of EHLLAPI

HLLAPI followed the use of 8086 Assembler as a means to integrate to the screen sessions active in the 3270 emulation portion of the device and featured accessibility from Compiled BASIC (which at the time was "it" for "High Level Languages" on the PC).

EHLLAPI adds the "Extended" to the HLLAPI API with a few additional synchronization and convenience functions. So, with just a few additions to the API a whole new acronym was introduced and today we treat both HLLAPI and EHLLAPI as one and the same, obsolete relics!

"Screenscraping" Has a Bad Name...Why?

EHLLAPI is, unfortunately, not that "high level" in that each and every operation needs to be performed using low-level parameters that have little resemblance to high-level data types. In fact, the parameters used in EHLLAPI are closer to machine registers for a specialized emulation integration hardware than they are to anything like a true API. Compared to the high-level workflow capture tools, screen field modeling, web service encapsulation of work processes and advanced testing tools provided by Flynet Viewer, EHLLAPI is stone-aged in comparison!

The use of EHLLAPI as a means of integration between the programs in the PC and the emulation sessions continued as the PC evolved, and multiple hardware/software developers introduced their own emulation solutions to the market. This was unfortunate for those needing to use the API, as the strict and limited parameter approach meant long and arduous coding, test and debugging cycles. In addition to the long development cycle, the obtuse nature of the API makes modifications very difficult. Due to the typical high change rate of screen-based applications this high maintenance cost added to developer frustration over the use of EHLLAPI in implementing screen integration projects.

Luckily for developers today, the use of EHLLAPI is no longer required, as vendors such as Inventu and Flynet have introduced very high level integration approaches (as well as supporting tools and runtime administration components). With these new, more productive and easily managed solutions, EHLLAPI can join the 3270PC in the PC Museum as a relic of the past.