marketrelations@nyiso.com writes to the NYISO_TECH_EXCHANGE Discussion List:

Dear Market Participants:

The NYISO back-up dispatch system is scheduled to be tested on Tuesday,
December 5.    The test will begin at about 10:30 a.m. and last for
approximately one hour.

Security Constrained Dispatch (SCD) will be stopped, but the mainframe 
computer
will
continue to operate, allowing the NYISO to monitor security.  If a situation
occurs, the
Shift Supervisor will be able to re-start SCD and take appropriate action.  
The
Market
Information System (MIS) and Balancing Market Evaluation (BME) will remain
available
during the test.

If you have any questions, please call Customer Relations  at 518-356-6060.