Computer term: "Extended System Configuration Data", a format for storing configuration information about plug and play (PnP) devices, present on a computer system, in the CMOS memory. The ESCD is read at boot-up, first by the BIOS and later by the operating system. The data is updated each time PnP-hardware is added or removed from the system, and it can also be manually overridden through the OS if desired.

The ESCD saves time and work for the BIOS since most of the time the hardware will not have changed each and every time the computer is started up, and the information in the ESCD can be used without any need for further configuration.