On Fri, 21 Aug 2009 14:24:00 -0500, Martin Kline <martin.kl...@yrcw.com> wrote:
> >"Native TCP/IP" may be at the wrong level. TN3270 runs over "Native TCP/IP" >and provides the protocol for positioning output data, identifying input data, >standardizing screen sizes in terms of character and line counts, etc. "Native >TCP/IP" would only provide message traffic, but no formatting. Perhaps I should have said a TCPIP socket application which is not dependent on VTAM. In fact, I was thinking more in terms of how X11 seems to work. > >Yet, any TSO replacement that expects to support the many existing ISPF >and other 3270-style data displays would have to still present data in a very >similar manner. Very true and a major "stumbling block". > >Also,I don't believe the issue is so much with the VTAM side of things, either. >VTAM can support full duplex just fine. > >Based on observation, I believe TSO applications are designed so that they >each expect to have full control of the display. Actually, after thinking about >it a bit, the line-mode (pre SPF) applications are entirely half-duplex functions. >Following in that design, ISPF does not allow subtasks to run (AFAIR) when >the application is waiting for input. Thus, having multiple tasks performing >separate functions and updating different parts of the display image is not >supported in TSO. > Perhaps what is needed is something akin to X11's control of the screen. Each application then has a logical screen which maps onto the physical screen. Each application updates it own logical screen, asynchronously. Only one screen receives keyboard / mouse messages. Or, perhaps simplest would be to just allow one TSO user to logon to multiple TSO session concurrently and run ISPF on each session. z/OS 1.10 now allows the sharing of ISPF profiles. But this does not address the original desire of having a field like a counter which is asynchronously updated. But that would be an application design issue if we could get around the implicit "half duplex" screen mentality of TSO. -- John ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@bama.ua.edu with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
