Buffalo Memory Starts to Ship Samples of MRAM-cache SSD

May 14, 2012
Motoyuki Oishi, Nikkei Electronics
The MRAM-cache SSD
The MRAM-cache SSD
[Click to enlarge image]

Buffalo Memory Co Ltd exhibited an SSD (solid state drive) using MRAM as cache memory at the 15th Embedded Systems Expo in Japan.

This time, Buffalo Memory showcased a 4-Gbyte SSD equipped with an 8-Mbyte MRAM cache. It is targeted at industrial instruments that are used at a temperature of about 85°C and require a high reliability. The company will start to sell samples of the MRAM-cache SSD to corporate customers who will embed the SSD in industrial instruments.

MRAMs are nonvolatile memories that use magnetic materials as elements and feature high-speed random access, high integration and nonvolatility. There are three advantages in using MRAM as cache, compared with normal high-speed SSDs that use volatile DRAM as cache.

First, the new SSD has an excellent resistance to power interruption. In the case of existing SSDs, when the power supplied from a system to an SSD is cut off, it is possible that data being written is lost or the SSD breaks down in the worst case. In many cases, these problems occur when data stored in DRAM is lost.

On the other hand, the MRAM-cache SSD does not lose any data stored in the cache even when the power supply to the SSD is cut off, preventing failures at the time of rebooting.

Second, the MRAM-cache SSD can improve booting speed. Normal high-speed SSDs read management data, which is often read and written, from NAND flash memory and write it in cache.

On the other hand, the MRAM-cache SSD stores management data in the cache (MRAM) even when power is not supplied to it. As a result, it becomes possible to reduce the number of processes that are necessary at the time of booting such as loading data and to reduce booting time of the SSD.

Third, the new SSD has an excellent power-saving capability. When the SSD is not accessed (such as reading and writing) for a certain amount of time, the power supply to the cache memory is cut off to drastically reduce power consumption. This was realized because MRAM can retain data without being powered and quickly restore to a previous state when the power supply is resumed.

Japan Technology Report

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