NVMe Hard Disk Drives (HDDs) are a new storage system product family currently going through development and validation. It’s expected that some of these products will be released in 2023 or 2024.
HDDs store memory on a spinning disk and are slower than solid-state drives (SSDs). So, why new HDDs? The new devices are said to use less power and cooling, making them more economical. They also simplify the interfaces needed to transfer data to them.
This would be particularly beneficial for data-center operators, providing an alternative to serial advanced technology attachment (SATA), serial-attached SCSI (SAS), and/or Fibre Channel (FC) devices, interfaces, and bridges.
Additionally, interconnect suppliers are working closely with OEMs and end-users to develop advanced, internal cable assembly and connector products. Much like NVMe SSDs, internal NVMe HDD connectors and cables are expected to gain market growth due to increasing demand in the coming years.
Both HDDs and SSDs use the same types of connectors and cables. By relying on the same interface protocol across different storage technology devices minimized latency and increases system efficiency.
As the latest NVMe HDDs become available, they could become more competitive compared to SAS and Fibre Channel (FC) devices in data center cool and cold-archiving applications and main-storage applications.
For SATA, SAS, and FC controller-chip companies, the rise of NVMe devices reflects a transition phase in the marketplace. NVMe works more closely with the motherboard, eliminating the need for a SAS or SATA controller.
Depending on the form-factor type (direct blade or box drop-in module), it’s possible that the new NVMe HDDs could use the internal, shielded SFF TA 1020 connector family or older universal type SFF-8369 connectors and internal cables — much like the popular NVMe SSD drives.
Although certain products might then need to comply with older, installed form-factor systems and could benefit from the use of an SFF TA 1016 connector and cabling system. The SFF TA 1020 and SFF TA 1016 offer different pin-count connectors available depending on the circuit design.
It’s expected that the NVMe 2.0 Specification will soon include information on the new NVMe HDD interconnections. The GenZ Consortium, which is made up of computer industry companies dedicated to creating and commercializing new data-access technology, has offered SFF TA 1020 specs related to the connector and cable assembly options that are based on the original SFF TA 1002 spec. It can support future speed rates to 56G and 112G PAM4 per-lane links.
SAS HDDs have a history of 11 technologies, with major product generations going back decades. Each generational spec typically included multiple new connector standards and cable-assembly family types, such as SCA, VHDCI, or HDminiSAS. This resulted in a large increase of inter-generational cable assembly adapters and single generation types.
The 11th generation INCITS T10 group’s most recent SAS 5.0 specification, as well as the GenZ and OCP NIC 3.0 spec, suggest using SFF TA 1002 or SFF TA 1020 connectors and cables. This is a somewhat rare agreement between several organizations about the application of the same connector specifications. This also occurred with the ubiquitous Type C connector with consumer and prosumer devices.
However, some large OEMs and end-user companies are using different connector types, which is typical in the storage industry.
Until the newer HDDs and related interconnections hit the market, that sector is trending downward compared to the rapidly increasing demand for newer storage devices, including SSDs.
The SFF TA 1026 is a competing shielded, internal storage connector and cabling solution, developed by Molex. These devices are only for 32G NRZ per-lane link performance (and cost) and target PCIe 4.0 16GT & SAS 4.0 22Gbps internal connector and cable applications.
The SFF TA 1026 specifications provide several detailed cabling solutions, which have mostly replaced the older PCIe 2.0 and PCIe 3.0 standard internal OCuLink connector and cable assemblies. Internal USB 4.0 TYPE C cables have also replaced OCuLink use in most new applications, such as with Server Firmware Porting.
The SFF TA 1016 non-shielded, internal connector and cabling option hit the storage market much later than the SFF TA 1002. Developed by Amphenol, the SFF TA 1016 comes in four major pin-count sizes and several orientations. It also competes with the older generation of the 24G NRZ per-lane SlimSAS and SlimLine internal, storage connectors and cables.
SATA HDDs have been losing the market share for some time now and have typically been replaced by SATA SSDs — which are also now, slowly losing the market share to NVMe SSDs. New interconnect requirements will likely be released soon for multi-activator drives, which are used in some of the newer SATA and SAS products (follow Seagate on the company’s connector use). Much of the remaining SATA internal connectors and cables business is in the mature stage of product life, supporting a large installed base.
FC HDDs have long been replaced in internal systems because FC is primarily a SAN external interface. However, there are FC Tape Drive systems that use internal custom cabling. Typically, next-generation FC switches and controller cards use internal and shielded SFF TA 1020 connectors and cables to support 112-124G PAM4 signaling.
Ethernet HDDs are a type of external drive designed to connect directly to network-attached storage (NAS) systems. In this case, mostly Ethernet external connectors and cables are used. These systems tend to be quite low-cost and represent a moderate portion of the HDD TAM market with some new growth still anticipated.
Observations
Aside from the newer HDD internal, shielded standard connectors and cables, there are also several new proprietary form-factor connectors and Twinax cable assemblies that are popular with storage-systems developers.
Driven by an increase in internal high-speed IO cabling applications and volume demand, some OEMs are relying on non-standardized supplier products. A few examples include Amphenol’s Overpass, Samtec’s SI-Fly, TE’s Sliver, and Luxshare Tech’s ULP high-speed IO interconnect product solutions. These devices can be found in some current and next-generation storage HDD and SSD systems.
HDD internal IO cable designers might also take advantage of a new, raw Twinax cable that could combine 3M flat foil-shielding and Luxshare Tech’s high-performance Optimax Twinax insulator and conductor. This is likely the goal of the companies’ new partnership.
Newer persistent memory devices will take some of the market share in certain storage applications as alternatives to well-established SSD or HDD technologies. Driven by OCP Consortia and other groups, these devices are smaller and use less power. They’d mostly use the SFF TA 1020 connectors and cables.
For the latest updates, consider reviewing the recent storage-related presentations made at the OCP Summit meeting day and the SNIA.org SDC conference. Check their websites and others, such as the SNIA/SFF and INCITS T10.org meetings. Also, use the SAS Integrators Guide for new topologies and interconnects. The SFF-9402 specifications provide insights for several different pinouts for internal storage drive-cabling and connector adaptors.
After decades of connector and cable options for storage systems, the market and its segments offer several options for high-speed HDDs and controllers. (I have been directly involved with developing 15 generations of storage interfaces and interconnects and am still astonished by the new technologies, forecasting, and solutions that evolve each year.)
