For decades, the goal has been to create a random access memory (RAM) that is non-volatile like flash storage but with the speed and addressability of a RAM chip. Such a technology would dramatically change the industry providing its cost was in line with flash memory chips.
The NAND flash memory commonly used in solid state drives (SSDs) is non-volatile, but it only reads and writes groups of bytes like a hard disk. RAM is much faster, but it can be read and written one byte at a time (see byte addressable
). However, RAM is volatile and loses its content when the power is off. See storage vs. memory
, flash memory
and chips vs. disks
A Paradigm Shift in the Future?
The interplay between main memory (RAM) and storage is how computers have operated since the 1950s. RAM is fast, byte addressable and volatile. Storage is block addressable and non-volatile.
Software and data are input from storage to RAM, and updated data are saved from RAM to storage. If storage were as addressable as RAM and as fast as RAM, the entire program and all the processing could take place in storage. Computers would always be "instant-on" and not waste AC or battery power when idle.
However, that shift is likely to be decades away. Although non-volatile, byte-addressable RAM memories are increasingly used as caches and as main memories in small devices, NAND flash storage chips are always getting faster, more dense and less expensive. See non-volatile memory