Exhibit 21.1

MDI, Inc. – Subsidiaries as of December 31, 2006

Name of Company	Jurisdiction	Status
United States
ABM Data Systems, Inc.	Texas	Active
Monitor Dynamics, Inc.	California	Inactive
American Building Control GP, Inc.	Delaware	Active
American Building Control LP, Inc.	Delaware	Active
MDI Operating, L.P.	Texas	Active
Global Systems Solutions, Inc.	Delaware	Active
Foreign
MDI S.A.	Switzerland	Inactive
MDI France, S.A.	France	Inactive
MDI, Inc. – Subsidiaries as of March 9, 2007
United States
ABM Data Systems, Inc.	Texas	Active
Monitor Dynamics, Inc.	California	Inactive
Global Systems Solutions, Inc.	Delaware	Active
Foreign
MDI S.A.	Switzerland	Inactive
MDI France, S.A.	France	Inactive