From: Aaron Bartell
We need to get a diagram in place as that was a good explanation to
give understanding of what parts are involved and what can be ripped
out and replaced with something else (i.e. the Web Client) portion.
I just see all kinds of possibilities. Niels' Virtual Terminal Interface maps 5250 streams to arrays of data structures that offer simple references to field attributes (row, column, length, & display atttributes). Perhaps the Workstation Extender simply passes that data along to the client in a JSON format.
It has been a while since I looked at the spec, but I don't recall the 5250 data stream having record names, field names, or data types. Perhaps Scott Klement or James Rich or someone who worked on the tn5250 project could shed more light on that.
However if you were interfacing with a Web client that needed additional meta data, you might be able to add that type of plumbing in a custom version of the Workstation Extender; possibly cross-referencing to DDS meta data based on screen title or other attributes found in the 5250 stream.
With a modular architecture like this, various Web Clients and Workstation Extenders could be plugged-in. Maybe one developer writes a Workstation Extender using IceBreak's support for Web Services, while another writes a Workstation Extender using CGIDEV2 and persistent CGI. The design is modular.
I've used the names Workstation Application, Virtual Terminal Interface, Workstation Extender, and Web Client. But perhaps Niel can clarify which of those parts fit into his name (IceCap). IceCap seems like a good name for the Virtual Terminal Interface, but I'm not sure what scope Niels had in mind.
Nathan.
midrange.com
