Re: Small screen problem

->From: neil@salmon.demon.co.uk ("Neil S. Briscoe") ->Subject: Small screen problem ->Date: Tue, 8 Jun 1993 17:04:17 +0000 ->Reply-To: neil@salmon.demon.co.uk ("Neil S. Briscoe") ->Organization: Bartec Medical Systems Ltd -> ->I'm having a small problem with what I believe are terminal modes ->getting set/unset by Informix. -> ->I have one routine that runs a report and pipes that to a pipeline ->that runs some C software to print bar codes and then pipes that to lpr. -> ->The labels come out fine, but after the routine finishes, the screen ->flashes off and on (that is, it is cleared and then redisplayed). ---------- Some but not all ports in some but not all versions [hoo, boy! how's that for definite?] of Informix include code to clear the screen before RUNning any command. The repaint then restores the screen after the RUN is complete. I encountered this problem, too. Screen flashed on Sun workstation running 4GL program built with Sun Unix I-4GL version 2.10. Screen did NOT flash on DOS workstation running SAME PROGRAM built with DOS I-4GL RDS version 2.10. ----------- -> ->On a Sun monitor, the output afterwards still looks OK. On vt100 type ->terminals (we've tried two different makes) the first line of a ->display array block is displayed one character to the left for the ->first two fields, the rest of the line (and the rest of the block) is ->displayed fine. ----------- This *might* be a termcap problem. Maybe the vt100 termcap does not have reset codes to correspond to the screen clear command being issued by Informix. I'm somewhat out of my depth here, so take this comment with a LARGE grain of salt. <:-( ----------- -> ->When the routine later clears the screen in accordance with the ->instructions in the software, the first letter of that mis-displayed ->line is left on the screen. ----------- This is because Informix is very "smart" about screen management. It only repaints what has changed, to reduce total I/O to the screen. This applies to screen clear also; Informix won't bother to blank areas that are already blank. Unfortunately, Informix doesn't know that the first characters are incorrectly positioned, so it does not blank them. If the user presses ^R, this tells Informix to refreash the entire screen, and it will clear up the garbage. It should also work for the mispositioned display array block. ----------- -> ->This does not happen with the VT100 terminals if hosted by an ancient ->Sun 3 machine and equally ancient Informix. It is notable that the ->screen does not flash either. ----------- See comments above about "some ports of some versions" ... ----------- -> ->Particulars: ->Sun 4/330 ->SunOS 4.1.2 ->Informix 4.10.UC1 -> ->Oh, the escape codes used to print the barcodes are definitely off ->and, in any case, the printer is not attached to the terminal but is ->on a separate line. -> ->Regards ->Neil ->-- ->Neil S. Briscoe Telephone: +44 252 376737 ->System Administrator Fax: +44 252 376644 -> Email: neil@salmon.demon.co.uk -> nbriscoe@cix.compulink.co.uk -> Regards, Alan ___________________________ ______________________| R. Alan Popiel |__________________________ \\ Internet: | Martin Marietta, Tech Ops | / \\ alan@den.mmc.com | P.O. Box 179, M/S 5422 | Std disclaimers apply. / )Voice: | Denver, CO 80201-0179 USA | ( / 303-977-9998 |___________________________| (But you knew that!) \\ /________________________) (____________________________\\