Terminal MODEL 6 support

Version 7.5 of Model 204 (and the Sirius Mods before that), adds support for terminal models beyond the standard MODEL 2 (24 X 80), MODEL 3 (32 X 80), MODEL 4 (43 X 80), and MODEL 5 (27 X 132). The new terminal models are supported by setting the terminal model to 6:

RESET MODEL 6

There is really no such thing as a Model 6 terminal, but setting the terminal model to 6 tells Model 204 to issue a Write Structured Field Query to the terminal to have the terminal indicate its geometry (number of rows and columns) to Model 204. In this way, Model 204 can dynamically set a terminal's geometry, whether it's one of the standard geometries (Mod 2, 3, 4, or 5) or not. Many terminal emulators allow alternate 3270 sizes to be set. This makes it possible to set the terminal geometry to match the optimal combination of font size and physical screen size for a particular workstation, rather than trying to set the emulator font size to work well with one of a limited number of screen geometries.

Unfortunately, the standard User Language screen definitions don't allow the defining of fields that extend beyond column 79. However, $ScrHide, $ScrSize, and $ScrWide make it possible for User Language screens to take advantage of columns beyond column 79. In addition, these functions make it possible to dynamically modify screen definitions to allow a single screen definition to work with an arbitrary variety of screen sizes. While these functions are a bit awkward to use and somewhat limited, they are not unreasonable for building dynamic scrolling screens — scrolling screens being particularly suited for larger screen geometries.

To facilitate SOUL applications for varying screen sizes, the VIEW command for the MODEL parameter has been enhanced to show the screen geometry in addition to the model number for Model 6 terminals:

> V MODEL MODEL 6 34*142 TERMINAL MODEL

Issuing $View for the above terminal returns a 6 34*142, from which a SOUL application can readily determine that the screen has 34 rows and 142 columns.

To enable Model 6 support, the SIRTERM system parameter must be set in the CCAIN stream.

If a terminal is using a non-standard screen geometry via Model 6 support, the Model 204 editor and command line will correctly use the available screen space. Many RKTools subsystems, such as those for SirScan, SirMon, and SirPro, and the SirFact product will also take advantage of the additional available screen space.

If the screen geometry of a Model 6 terminal requires more than 6142 bytes, screen backpaging will be disabled.