2005: Perpendicular Magnetic Recording arrives
PMR raises disk drive areal density above 100 gigabits per square inch
Perpendicular magnetic recording (PMR) bits align vertically and offer a significant increase in areal density compared to conventional longitudinal magnetic recording (LMR) technology. Ampex engineers had evaluated PMR for tape and IBM investigated the technology for the IBM 1301 drive but it did not reach commercial application until 2005. The combination of PMR media and shielded magnetoresistive (MR) head technology enables multi-terabyte drives with areal densities approaching one trillion bits/sq. inch.
The bit size supported by a magnetic medium is inversely proportional to its coercivity and coercivity is limited by the magnetic field achievable by the write element of the recording head. The combination of optimized PMR media and head approximately doubles the magnetic write field achievable with LMR. A stronger write field enables the use of higher coercivity media with smaller bit sizes and higher areal density. Disk media with magnetic crystallites oriented perpendicular to the surface and isolated from each other by oxide barriers used in combination with shielded write heads have extended HDD areal density by a factor of 10 since the introduction of PMR.
At Tohoku University, Japan, professor Shun-ichi Iwasaki championed PMR from the middle 1970s. In 1995, following Professor Stan Charap’s prediction that the areal density of longitudinal recording would be limited by superparamagnetism, it was recognized at a National Storage Industry Consortium (NSIC) – sponsored workshop that perpendicular recording could be extended to higher densities. Toshiba, Seagate and HGST led the commercialization of PMR disk drives between late 2005 and mid-2006. The Toshiba MK4007GAL featured an aerial density of 133 Gbits/sq. inch. All major industry vendors adopted PMR technology and within two years HGST introduced a one terabyte (1TB) drive, the Deskstar 7K1000, with an areal density of 325 Gbits/sq. inch.
Contemporary Documents
- Iwasaki S. “A study for the future of the magnetic recording: the possibility of the perpendicular magnetic recording” Abstract 1st Topical Symposium of the Magnetics Society Japan, 1977, republished in J. Magn. Soc. Jpn. 1 (1977) pp. 5–11 (in Japanese)
- Iwasaki S. “Perpendicular magnetic recording” IEEE Transactions on Magnetics (Vol: 16 No: 1, 1980) pp. 71–76
- Iwasaki S. “Perpendicular magnetic recording—Evolution and future” IEEE Transactions on Magnetics Vol: 20 No: 5 (1984) pp. 657–662
- Khizroev, S. and D. Litvinov. Perpendicular Magnetic Recording Kluwer Academic Publishers (2004)
- Mallary, M. et al. “One Terabit per Square Inch Perpendicular Recording Conceptual Design” IEEE Transactions on Magnetics (Vol: 38 No: 4, 2002) pp. 1719-1724
- Merritt, Rick, “Hard drives go perpendicular” E. E. Times (9/26/2005) (Retrieved on 4.20.15 from: http://www.eetimes.com/document.asp?doc_id=1156534&page_number=1)
- Lu, P. and Charap, S. H. “Thermal instability at 10 Gbit/sq. inch magnetic recording”, IEEE Trans. Mag. (Vol: 30, No: 6, 1994) pp. 4230-4232
- Perenson, Melissa J. “Hitachi Introduces 1-Terabyte Hard Drive” PCWorld (Jan 4, 2007) (retrieved on 9.12.15 from: http://www.pcworld.com/article/128400/article.html)
- “Seagate Introduces World’s First 2.5-Inch Perpendicular Recording Hard Drive” Seagate Press Release (June 8, 2005)
- “Hitachi's New "Super-Pendicular'' Hard Drive Shows Steely Reliability” HGST Press Release (May 15, 2006)
- “Hiatchi ships millionth perpendicular recording hard drive” HGST Press Release (November 1, 2006)
More Information
- Hoagland, A. S. “High Resolution Magnetic Recording Structures” IBM Journal of Research and Development (Vol: 2 No: 2, 1958) pp. 90-104
- Hoagland, A. S. “History of magnetic disk storage based on perpendicular magnetic recording” IEEE Transactions on Magnetics (Vol: 39, No: 4, 2003) pp. 1871 – 1875
- Iwasaki, Shun-ichi. “Perpendicular magnetic recording—Its development and realization” Proc Jpn Acad Ser B Phys Biol Sci. (Vol: 85 No: 2 Feb 2009) pp. 37–54 (Retrieved on 5.5.15 from: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3524294/)
- Richter, H. J. “The transition from longitudinal to perpendicular recording” J Phys. D. Appl. Phys. 49 R 149 (2007)
- Tanaka, Yoichiro. “Perpendicular Recording Technology: From Research to Commercialization” Proceedings of the IEEE (November 2008) pp. 1754 – 1760 (Retrieved on 5.11.15 from: http://ieeexplore.ieee.org/ieee_pilot/articles/96jproc11/jproc-YTanaka-2004309/article.html)
- “Perpendicular Magnetic Recording Technology” HGST Whitepaper(November 2007) (Retrieved on 4.20.15 from: http://www.hgst.com/tech/techlib.nsf/techdocs/F47BF010A4D29DFD8625716C005B7F34/$file/PMR_white_paper_final.pdf)
Oral Histories
- “Chen, Tu oral history” Computer History Museum Oral History # 102657958 (2005-10-28)
- "International Business Machines (IBM) Random Access Method of Accounting and Control (RAMAC) oral history panel" Computer History Museum Oral History # 102657937 (2004-10-29)
File name: 2005_PMR_v9
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