NVRAM chips do not lose information when the main power is turned off. NVRAM is an acronym for non-volatile random access memory (NVRAM). The volatility of a computer memory type is measured by whether the data is refreshed, or requires refreshing, after power is disconnected. In computer systems, early forms of random access memory (RAM) required continuous connection to a power source in order to retain memory. In fact, the original CMOS battery was designed to keep the BIOS settings in the volatile memory of the complementary metal oxide semiconductor (CMOS) integrated circuit (IC) system so that a computer could boot if power was discontinued.
With the advancements in the processes and technologies used in the manufacture of semiconductors, the production of NVRAM chips has proliferated. The most recent advancements have been implemented on the Itanium line of Intel ICs. Itanium computer memory chips are manufactured using the extensible firmware interface (EFI) specification. This standard defines the way the firmware encoded on the NVRAM chips should interface with the operating system. The internal commands in the EFI 1.10 specification, the boot menu, and the boot option maintenance menu are all written to the NVRAM chip so that the firmware layers can be loaded through a pre-boot execution environment prior to execution of the EFI shell and eventually the operating system. Today, ICs that use NVRAM chips are supported by more operating system vendors. In addition, device driver programming for NVRAM systems has extended even into the open source community. NVRAM chips are also commonly used in modems. This enables the specific IP and router table information to be retained, allowing the data to be reacquired if it becomes corrupted or unstable for any reason simply by rebooting the modem.
Suppliers of NVRAM chips have made recent advances in NVRAM types. A relatively new form of NVRAM is ferroelectric random access memory (FRAM). FRAM chips are physically constructed like dynamic RAM (DRAM), but with the addition of a ferroelectric film. This film permits the retention of an electric field that can force a write or rewrite of data, depending on the magnetic polarity at the time the voltage is read.