What Is NVRAM?
NVRAM is a non-volatile memory that retains its stored contents even when the power is turned off, and is a semiconductor memory that can be freely read and written.
It stands for non-volatile random access memory and is read as NVRAM. However, NVRAM is not a memory chip that will never lose data; it is a consumable product that can continue to retain data with its built-in battery. Therefore, when the battery runs out, it will no longer be usable. The built-in battery is usually contained in the plastic package of the device and is difficult to replace.
Uses of NVRAM
NVRAM is non-volatile memory, a general term for flash memory and other devices that can be read and written in the same way as RAMs. It is used in a variety of places, such as computer monitors, printers, and devices that need to store settings, such as automobiles and smart cards.
For example, RTCs on computer motherboards are battery-backed NVRAMs that use CMOS batteries to store the date and time.
Principles of NVRAMs
NVRAMs are non-volatile RAMs, which are SRAMs with battery-powered backup to enable data retention when the power is turned off. Since it is essentially an SRAM, data can be written to it faster than to an EERPOM or flash memory.
However, it requires a battery, and the battery must eventually be replaced. Therefore, if the battery runs out, all data will be lost.
Macintosh used to use PRAMs, but since the introduction of Intel CPUs, NVRAMs are used to store Macintosh configuration information, such as the startup disk, display resolution, speaker volume, and user-set date and time information. The configuration information is stored in NVRAM.
The MAC address of the SPARCstation’s Ethernet is also stored in NVRAMs, not ROM. There is a problem with the Mac address changing when the battery runs out.