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Error: NDP error - invalid number integer overflow

Solution or Workaround

Description

ARCPLOT PLOTZOOM and ARC DRAW sometimes stop drawing or draw with a purple spike. Other times they produce the following messages:

"NDP error - invalid number integer overflow or 0/0
see section b.2 F77L manual
called by Draw
called by move
called by fdwplt
called by fdwplp
called by fdwplz
called by exe811
called by execut
called by arcplt"

The latter requires a reboot.

Cause

The default display driver IBMVGA.SYS.

Solution
Change the display driver to HRVGA.SYS -STANDARD 640x480 VGA.