Xerox 721 Message Manual page 223

SYSTEM VERIFICATION ERROR MESSAGES
No graphics memory.
All banks of graphics memory appear to be missing or have failed
testing.
Operating in degraded mode.
A problem was detected during system verification. (Message
appears for any system verification error that occurs; other
messages follow, describing the specific error.)
System not operational.
Either devices appear to be missing, main memory below 128K is
missing, or there is no font memory available. (Other messages
appearing on display will define the specific problem that exists.)
If this message is displayed, the system will be unable to function
even in a degraded mode.
Updates Non-Volatile Memory locations:
The parameters you have specified have updated existing non-
volatile memory (NVM) data.
Action None.
XEROX 4635 LASER PRINTING SYSTEM MESSAGE GUIDE 13-3