Re: 5250 to Web Interface / Application Modernization

Nathan please see below.


Jon Paris

www.partner400.com
www.SystemiDeveloper.com

1. Server-based display files contain I/O elements, positioning,
attributes, subfiles, etc.

Display files are indeed used as a convenience. A subfile is simply a list so you're going to need on one way or the other and a subfile is easy to use and familiar in concept for the audience. But positioning is not used and neither are attributes by default - although commercial OA handles will interrogate the display file and use them.

2. Workstation data management.

No used - period. And there was you trying to convince me you knew OA <grin.

3. Proprietary data streams.

Nope. The handler determines what the data stream looks like. OA either presents you with a buffer or presents a field at a time. Handler chooses which thy want.

4. Browser-based emulator that transforms proprietary data streams into
browser DOM objects.

Not an emulator - and the "proprietary" stream the days is usually JSON - but it can be anything so hard to think of it as proprietary. Certainly OA place ZERO requirements on the stream - that's the whole point.

5. Traditional op-codes EXFMT, WRITE, READ, ETC.

Yup. That is the point. BUT _because_ data management is not involved they do not have the same limitations as in a 5250 app. Just for one example, a READ can only read a format that has already been written to the display - an OA program has no such restriction - it can read the file and process any format sent. There is also, as Joe pointed out I think, no requirement that the same program that "owns" the screen provide all the responses. The browser can request data from any source. Another program a stored procedure, a web service, etc.

In your earlier writing you liked to distinguish between "server-client"
which was your label applied to IBM's workstation data management vs.
"client-server" which was applied to "newer architecture".

Given my observations about OA architecture and implementations (1-5, etc.)
How is that incrementally moving toward a newer architecture?

Maybe given my observations of your view of the OA architecture you might want to restate this.