– The development of SSD system semiconductors applied with flash-dedicated on-chip network technology is expected to provide an upper hand advantage in the next-generation high-performance SSD market.
– Reduction in response time by up to 31 times compared to existing systems, and lifespan increase by 23%.
– Expected to contribute to the improvement of various algorithm performances that utilize AI research and big data analysis technology.
The importance of data continues to increase as more data is needed for AI training along with the demand for high-performance SSD (Solid State Drive, a storage device using semiconductor memory) products, which are major storage devices for data centers and cloud services.
However, high-performance SSD products have faced the limit of tightly-coupled structures making it difficult to maximize SSD performance.
To address this problem, Professor Kim Dongjun (John Kim)’s research team developed the world’s first SSD system semiconductor structure that not only drastically increases the read/write performance of next-generation SSDs through the development of high-performance modular SSD systems, but also extends the lifespan of SSDs.
Professor Kim Dongjun’s team identified the limitations of the tightly-coupled structure inherent in traditional SSD designs, and proposed a de-coupled structure that maximizes performance by building a flash memory dedicated on-chip network inside the SSD based on on-chip network technology, which is mainly used in non-memory system semiconductor designs like CPUs and GPUs.
This technology, dubbed ‘modular SSD,’ allows packet-based data to be freely transmitted within the chip, which reduces the interdependence of SSD’s front-end and back-end designs and allows for independent design and assembly.
*On-chip network refers to the packet-based connection structure for elements inside a chip used in system semiconductor design such as CPUs and GPUs. It is one of the essential design elements for high-performance system semiconductors and becomes increasingly important as the size of the semiconductor chip increases.
The modular SSD system structure developed by Professor Kim Dongjun’s team refers to components near the SSD as front-end and those closer to the flash memory as the back-end, based on the internal components of the SSD controller and the flash memory interface. They proposed a de-coupled structure that minimizes performance degradation by newly constructing a flash memory dedicated on-chip network that allows data movement between flash controllers in the back-end.
By accelerating some functions of the flash translation layer, which is the core element driving the SSD,they created an opportunity to actively overcome the limitations of flash memory through hardware.
The ‘modular’ SSD structure has an advantage in that the de-coupled structure does not limit the flash translation layer to the characteristics of a particular flash memory and provides the convenience of design that allows independent performance of front-end and back-end designs.
Through this, response times were reduced by 31 times compared to existing systems and SSD lifespan was extended by about 23% by applying it to SSD bad block management, according to a research team official.
This study, in which Jiho Kim (PhD candidate in the School of EE at KAIST) participated as the first author and Professor Jung Myoungsoo as the co-author, is to be presented at the ’50th IEEE/ACM International Symposium on Computer Architecture (ISCA 2023)’, the most prestigious international academic conference in the field of computer architecture, held in Orlando, Florida, USA, on June 19th. (Paper titled: Decoupled SSD: Rethinking SSD Architecture through Network-based Flash Controllers).
Professor Kim Dongjun, who led the research, said, “This research is significant in that it identifies the structural limitations of existing SSDs and applies on-chip network technology centered on system memory semiconductors like CPUs to actively perform necessary tasks with hardware, and is expected to contribute to the next-generation high-performance SSD market.”
He explained the significance of the research, adding that “the de-coupled structure has various uses as it is not limited to performance alone as an SSD structure that operates for lifespan extension.”
An official explained that this research carries significance as it was conducted through the collaborative research of two world-class researchers: Professor Jeong Myoungsoo, a prominent researcher in the field of computer system storage devices at KAIST, and Professor Kim Dongjun, a leading figure in the field of computer structure and interconnection networks.
