The Central Mainframe Access feature was introduced on May 5, 2010. In order to gain access to the mainframe, you need a secret code that can be obtained by doing jobs in any of the four permanent cities. The code is a 10-digit hexadecimal number that allows you to access the mainframe once every 24 hours. According to the code popup, the number will not change. When this feature was introduced there was not a way of retrieving your code, short of e-mailing Zynga support. File:SecretCodeMW.png