Universal memory

Universal memory refers to a hypothetical computer data storage device combining the cost benefits of DRAM, the speed of SRAM, the non-volatility of flash memory, and infinite durability. Such a device, if ever it becomes possible to develop, would have a far ranging effect on the computer market.

Computers for most of their recent history have depended on several different data storage technologies simultaneously as part of their operation. Each one operates in a place where another would be unsuitable. For instance, a personal computer might include a few megabytes of fast but volatile and expensive SRAM as a CPU cache, several gigabytes of slower DRAM for program memory, and multiple hundreds of gigabytes of the slow but non-volatile flash memory or a few terabytes of "spinning platters" hard disk drive for long term storage. Researchers seek to replace these three different memory types with one single type to reduce costs and increase performance.

For a memory technology to be considered a universal memory it would need to have characteristics from several different common storage technologies. It would need to be able to operate very quickly, with a practically unlimited number of read/write cycles, while still being affordable enough to serve the ever increasing demands for mass storage.

Many types of memory have been researched in the hopes of creating a practical universal memory type. These include:

• magnetoresistive random-access memory (MRAM)
• Bubble memory
• Racetrack memory
• ferroelectric random-access memory (FRAM)
• phase-change memory (PCM)
• programmable metallization cell (PMC)
• resistive random-access memory (RRAM)
• Nano-RAM
• Memristor-based memory

For various reasons, none have yet achieved all three goals.