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

HLLAPI, or the High Level Language Application Programming Interface, was first introduced soon after the introduction of the IBM 3270PC, which 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.

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).

HLLAPI 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 HLLAPI 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 Inventu Viewer+, EHLLAPI is stone-aged in comparison!

The use of HLLAPI 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 HLLAPI in implementing screen integration projects.

Luckily for developers today, the use of HLLAPI 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, HLLAPI can join the 3270PC in the PC Museum as a relic of the past.

A Future for Your HLLAPI/WinHLLAPI Applications and Macros?

With the Inventu Viewer+ server-side support for the HLLAPI interface, you can move to a better architecture (Inventu Viewer+ Pure HTML terminal emulation) while retaining your existing HLLAPI applications.

Inventu are experts across all screen integration API's and can help you convert existing Windows applications or Desktop Emulator Macros to server-side applications or Server Macros.

Ask us about our VBA Macro converter that includes support for Dialog Boxes and Excel Integration!

Inventu Viewer+

Inventu Viewer+ delivers un-matched host access options including the best solution available today for web-based terminal emulation. At its core, Inventu Viewer+ utilizes and delivers on the latest, non-proprietary Web deployment technologies. Inventu Viewer+ is a modern, server based solution for businesses looking t​​​o connect to host systems such as UNIX, VMS, IBM Mainframe and iSeries. It can be used for terminal emulation, as well as host integration, modernization and migration​.

For more information click here: Inventu Viewer+ Product Information

Inventu Corporation

Inventu provides our Customers with software and services to implement new applications that support business initiatives. Inventu concentrates on using, replacing and renewing existing (legacy) applications using our original product, Screensurfer and our latest and greatest creation, Inventu Viewer+.

For more information click here: Inventu Home Page