Without a valid GAMS license the system will operate as a free demo system with these limitations:
The GAMS log will indicate that your system runs in demo mode:
GAMS Rev 227 Copyright (C) 1987-2008 GAMS Development. All rights reserved Licensee: GAMS Development Corporation, Washington, DC G871201/0000CA-ANY Free Demo, 202-342-0180, firstname.lastname@example.org, www.gams.com DC0000 --- Starting compilation ...
GAMS will terminate with a licensing error if you hit one of the limits above.