Today, MRAM (magnetic RAM) supplier Everspin announced that it expects to close out FY 2011 with a shipment volume that exceeds that of 2010 by more than a factor of three. MRAM combines the thin-film magnetics initially developed for the hard disk industry with the manufacturability of nanometer CMOS. MRAM can deliver DRAM-like speeds (tens of nsec) and Flash-memory-like long-term data retention (on the order of decades) without a significant wearout mechanism. Consequently, cost-competitive MRAM—if and when it appears—presents a real rival to both DRAM and NAND Flash memory.
Currently, MRAM is not cost competitive with DRAM or NAND Flash memory on a per-bit basis, but the technology is already finding niches where its cost and capabilities fit well. One such application is in the use of journal memory in RAID systems. From the Everspin site:
“MRAM performs the write journal or data log function in RAID disk arrays to capture transaction information in real-time so that data can be recovered should a system failure occur. Data logs also capture system conditions and status for remote diagnostics and repair.
Dell uses MRAM as a Raid-On-Chip journal memory solution for its Dell PowerEdge servers and PowerVault Direct Attached Storage (DAS), as well as Dell EqualLogic Storage Area Network (SAN) arrays. In these applications, MRAM provides enhanced data center fault recovery, reduced system downtime and lower total cost of ownership.
MRAM is the journal memory on LSI Corporation’s RAID controller cards featuring 6Gb/s and 12Gb/s SAS storage connectivity. MRAM chips are also included on LSI reference designs for third party RAID cards and RAID-on-Motherboard (ROMB) solutions.”
According to Everspin’s release, it has more than 300 active customers buying more than 100 part numbers in “three major markets” with more than 100 applications.”
Most design engineers these days cannot remember when magnetic memory was the memory of choice for computing equipment but core memory started its rise to prominence in 1953 when core memory was installed in the MIT Whirlwind computer. Magnetic core memory then reigned for 20 years as the king of memory for mainframes and minicomputers. It was even used in small quantities in computing equipment as small as the Apollo Guidance Computer that incorporated 2K words of core memory and the Hewlett-Packard 9100A desktop calculator that used a much smaller 2208-bit magnetic core memory to store the contents of its X, Y, and Z floating-point accumulator/registers. Even the US Space Shuttle employed core memory until 1990 but by then core memory’s usage had dropped to nothing.
The introduction of the Intel 1103 DRAM in 1970 presented the first real challenge to magnetic-core memory. In fact, the DRAM presented such an effective alternative that magnetic core memory essentially disappeared by 1975 (according to Wikipedia). Now, it might be DRAM’s turn.
Note: For more information on MRAM, see: