At the recent Magnetism and Magnetic Materials (MMM) Conference, put on by the IEEE Magnetics Society and the American Physical Society, several speakers spoke about advances in hard disk drive technology and Spin-based non-volatile memory devices. Hard disk drives are a popular digital storage technology for low cost digital storage. As pointed out in recent blogs HDDs have been announced with up to 10 TB of storage capacity in 2015. However a real roadmap for HDD technology has been difficult to come by. The development of 8 and now 10 TB drives involves the introduction of a few technologies such as shingled magnetic recording (SMR) and hermetically sealed He-filled hard disk drives. Coughlin Associates is the organizer of the 2015 Storage Visions Conference and publishes a report on emerging non-volatile memory technologies.
The SMR technology probably cannot add too much more to areal density growth and putting helium in a hard drive can only allow adding so many more disks to a drive. Thus higher storage capacities requires the introduction of new digital storage technology. The Advanced Storage Technology Consortium (ASTC) released the 2014 roadmap for HDD areal density (the amount of digital storage that can be stored on a given surface area of a HDD). According to the ASTC road map Heat Assisted Magnetic Recording (HAMR) should be introduced into HDDs by 2017, increasing the average annual areal density growth rate to 30% (it is currently about 15%).
Interestingly, the roadmap shows that a technology called bit pattern media (with the magnetic media broken into small regions on the disk surface) will be introduced about 2021 combined with SMR or an extension to SMR called Two Dimensional Magnetic Recording (TDMR). This will rapidly be combined with HAMR, which will result in up to 10 Terra-bit per square inch (Tbpsi) areal densities by 2025. Note that today’s HDDs have an areal density as high as 0.86 Tbpsi. This implies that a 3.5-inch HDD built with that technology could have about 10 X the capacity of the 10 TB HDDs in 2025, or 100 TB.
The MMM conference featured several sessions focused on the latest research on magnetic spin-based storage and processing technologies. The electrons that create current in current electronics also have a property called spin. The spin of electrons is associated with a magnetic field. The read sensors in HDDs have used spin-based technology as very sensitive magnetic field detectors for well over 15 years and the technology is now being developed for use in solid-state storage technology.
These spin-based magnetic random access memory (MRAM) technologies are the most promising technologies for replacing the semiconductor-based SRAM and DRAM that are the expensive main memory in most computers with a non-volatile memory technology. MRAM devices retain their memory when the power is turned off while SRAM and DRAM require regular doses of electrical energy to keep their memory. In addition to possible replacement of the main semiconductor memory in computers, MRAM can be used as a cache memory and is attractive for cache memory in storage devices such as HDDs, SSDs and RAID cards.
It was as interesting to see who attended these sessions as what was presented. The spin-technology sessions were well attended by technologists from all the HDD companies, semiconductor companies, spin tunnel MRAM start-ups and companies making SoC (System on Chip) devices that are the basis of many consumer and enterprise systems. This technology appears to be hot right now and the recently announced partnership between the MRAM company, EverSpin, and Global Foundaries indicates the looming expansion of this market into more mainstream applications.
Magnetic technology for storage and memory is developing to meet the needs of future mass-storage markets even as flash-based technologies eat away at higher performance markets. You can find out more about the development of HDDs, flash memory and spin-based MRAM devices at the Storage Visions Conference, January 4 & 5, 2015 in Las Vegas, www.storagevisions.com.
