Seagate has designed a pair of custom RISC-V cores to be used in future products as next-generation storage controllers. The chips, which are not referred to by any codename or brand, come in two flavors: A high-performance core and an area-optimized core. The high performance core has already been built “with RISC-V-enabled silicon,” while the smaller core “has been designed and is in the process of being built.”
The phrase “RISC-V-enabled silicon” is a little odd — we wouldn’t normally say “ARM-enabled silicon” or “x86 enabled silicon,” but since they seem to go on to refer to tapeout and initial foundry work on the other chip, the most likely explanation is that Seagate has is qualifying its high-performance chip for future shipping products, while the area-optimized core is a few steps farther back in the process.
“Having shipped close to one billion cores over the last year, Seagate has developed significant expertise in system-on-a-chip design,” said Cecil Macgregor, Vice President, ASIC Development. “We now expanded the capability to add customized RISC-V cores to our portfolio, which is critical to future products. We live in a time of unprecedented growth of enterprise data—and much of this data is in motion. These cores will allow devices to share a common RISC-V ISA. Using open security architectures, they will enable more secure movement of data.”
The high-performance core offers up to 3x the performance “for real-time, critical HDD workloads.” Seagate claims the chip allows for improved fine-grain movement control compared to previous solutions, because the new core uses more advanced servo algorithms.
The small, area-optimized core is intended for background and auxiliary tasks, and can function as a limited security processor, “targeting a small-footprint implementation of security features over performance.”
Seagate isn’t kidding when it claims that it needs more advanced servo algorithms. According to John Morris, Seagate’s Chief Technical Officer, the 50TB capacities Seagate envisions for future disks will require the read-write transducer to fly across the disk at 2.5 meters per second, while also keeping its position on the drive accurate within just 2.4nm. Meeting these challenges required a new core.
This kind of chip could also be used for an SSD controller, but Seagate uses third-party controllers for its branded SSDs (at least so far) and has not announced any kind of equivalent effort for that side of its business. Exact performance numbers for these new cores also have not been released.
Seagate is the latest high-profile customer to announce it has designed a custom RISC-V core. The open-standard ISA was explicitly designed to appeal to a wide range of customers and use cases. Alibaba, SiFive, and Western Digital have all built proprietary cores around the ISA. Wikipedia lists roughly two dozen projects by various companies. Most are focused on proprietary cores, but there are some open source hardware designs for RISC-V as well.