Typeahead Enhancements

As of HP-UX 10.0, VT3K/9000 supports the single-echo typeahead capability needed by MPE/iX applications that use FDEVICECONTROL 192 with control directives 51 (enable/disable typeahead) and 63 (enable/ disable single/double echo) set in parm1.

Only directives 51 and 63 related to the typeahead and echo setting are supported. For example, directives 60 and 61 are not supported. When using directive 63, only requests for setting single-echo mode will be supported. A request to set double-echo mode returns an error.

Prior to HP-UX 10.0, the vt3k -t option allowed you to type in commands before the actual read was posted from MPE/iX. The -t option now allows you to turn on the MPE/iX style single-echo typeahead as if you either programmatically turned it on from an MPE/iX application using FDEVICECONTROL or used the command SETVAR HPTYPEAHEAD TRUE.

Since the -t option turns on single-echo typeahead on the HP-UX side, if you were to use the command SHOWVAR HPTYPEAHEADon MPE/iX to check the status of the HPTYPEAHEAD variable, it would still be set to FALSE though VT3K/9000 would operate in single-echo typeahead mode. To avoid confusion, use the SETVAR HPTYPEAHEAD TRUE rather than the -t option.

	CAUTION: If you intend to run block-mode applications, you should not open a VT3K/9000 session with the -t option.