Flash Core Module

RamSan-500 enterprise solid state disk from Texas Memory Systems

On September 17, 2007, Texas Memory Systems (TMS) announced the RamSan-500, the world's first enterprise-class flash-based solid state disk.[2] The Flash Modules were designed from the ground up by Texas Memory Systems using a proprietary form-factor, physical connectivity, ECC algorithm, and flash wear-leveling algorithm. The flash controllers used specialized logic that enabled lower latency than any other commodity controller could achieve.[3][4] This product marked the beginning of development of the RamSan-OS, which was a custom designed flash management and storage infrastructure management suite implemented in both software and hardware.[5] Six more generations of this flash controller were developed (for a total of seven generations), until IBM acquired TMS in 2012.[6]

On January 16, 2014, IBM announced the FlashSystem 840 product, which was the first FlashSystem designed entirely by IBM post-acquisition of TMS. IBM branded the flash controller technology IBM MicroLatency technology, and touted how the technology lowered data access times from milliseconds to microseconds.[7]

On February 19, 2015 IBM announced the FlashSystem 900 and V9000 products and re-branded the flash controller technology as IBM FlashCore technology, and described it as the suite of innovations and capabilities that can enable FlashSystem to help deliver better performance than enterprise disk systems. The flash modules themselves continued to be branded the IBM MicroLatency Modules. This version of the technology supported Micron's MLC flash chip technology.[8]

With the announcement of the FlashSystem 9100 on July 10, 2018, FlashCore technology was re-implemented into a standard 2 1/2 inch NVMe SSD form factor. This marks the first time that the original technology developed by TMS was packaged in such a way that conformed to an industry specification and was interchangeable with industry-standard SSDs.[9]

IBM FlashCore utilizes FPGAs and NAND flash memory chips from off-the-shelf vendors to implement the entire data path is in hardware. Each Flash Module contains a gateway (implemented in an FPGA) and up to 8 flash controllers to efficiently distribute I/Os to the NAND flash chips. Firmware resides on a microprocessor and is only invoked for garbage collection management or when there is some problem than cannot be resolved by the hardware logic.[10] The controller design for IBM FlashCore uses techniques such as health binning, heat segregation, read voltage shifting, and hard decision error correction codes to lower read and write amplification and to provide consistent low latency.[11]

In April 2017, IBM's flash portfolio represented more than 380 patents.[12] The IBM FlashCore technology implements patented Variable-Stripe Raid (VSR) [13] to increase the resiliency of stored user data.