Damped Hard Drive Mounting

Disclosed herein is a system for mounting a hard disk drive to a rack of a data center. A grommet is optimized for limiting the vibrational forces between the hard disk drive and the rack. Particularly, various grommet designs are optimized to limit the vibrational forces imparted on the rack such that neighboring hard disk drives are not affected by the vibrational forces emitted by neighboring hard disk drives, thereby increasing the lifespan of the grommets and hard disk drives and allowing the hard disk drives to be replaced quicker. The grommets are designed to have different stiffnesses and materials such that a user can select an appropriate grommet that corresponds to the hard disk drive implemented on a particular rack

Enabling the recycling of rare earth elements through product design and trend analyses of hard disk drives

Hard disk drives consist of a complex mix of various materials. While Aluminum, Copper and Steel are easy to separate, actual recycling processes dilute containing rare earth elements to non-recoverable grades in other material streams. To enable future recycling of these materials an in-depth analysis of hard disk drives from Desktop PCs and Notebooks was carried out. Furthermore, possible recycling strategies for rare earth elements were derived and the recycling potential was assessed. The results show high concentrations of Neodymium (22.9 ± 2.8 %), Praseodymium (2.7 ± 2.2 %) and Dysprosium (1.4 ± 1.5 %) in the magnets. Various types of alloys are applied for different technical or economic reasons. Also a dependency from manufacturing dates was evidenced. Furthermore, Cerium (0.5 %) and Neodymium (0.2 %) were determined in printed circuit boards. Test disassemblies of hard disk drives showed a complicated structure and thereby a difficult access to the NdFeB magnets. This applies explicitly for the spindle motor magnets, which hold the main share of applied Dysprosium. A WEEE collection analysis shows an amount of about 12.7t magnets from hard disk drives from PCs in Germany in 1 year. Put-on-market data predict decreasing shares of hard disk drives from Desktop PCs and significantly increasing amounts of Notebook components in WEEE

A Rule Based Forecast of Hard Disk Drive Costs

While the cost of storage devices such as hard disk drives continues to fall, the overall proportion of computer network costs dedicated to storage continues to rise. Within a few years, storage will account for 50 percent of total network hardware and software costs. Since computer networks typically have long lives, the design process often involves projecting costs many years into the future. This paper examines a rule based on a technology trend that can be used to estimate the cost per megabyte of hard disk drives. The rule is similar to the well-known Moore’s law that has reliably summarized integrated circuit advances over the past several decades. A statistical analysis of historic data suggests the rule for hard disk drives captures much of the readily available information

A Note on Disk Drag Dynamics

The electrical power consumed by typical magnetic hard disk drives (HDD) not only increases linearly with the number of spindles but, more significantly, it increases as very fast power-laws of speed (RPM) and diameter. Since the theoretical basis for this relationship is neither well-known nor readily accessible in the literature, we show how these exponents arise from aerodynamic disk drag and discuss their import for green storage capacity planning.Comment: 5 pages, 3 figure

Maximizing Minimum Pressure in Fluid Dynamic Bearings of Hard Disk Drives

We focus on the central spindle which supports the rotating magnetic platters which hold all of the data. The spindle must operate with great precision and stability at high rotational speeds. Design practice has converged on oil-lubricated hydrodynamic journal bearings as the most common choice for spindles. That is, a layer of viscous oil separates a rotating shaft (the bearing) from the fixed outer sleeve (the journal). In hard drives, it is very important for the shaft to be centered within the sleeve. Plain journal bearings (i.e. both surfaces are circular cylinders) are unstable to perturbations that push the shaft off-center. It was found that this stability problem can be overcome by cutting diagonal grooves into the journal in a pattern called a herring-bone. Another consequence of this design is that very high pressures are generated by the grooves as they drive the oil to the middle of the bearing, away from the top/bottom ends of the spindle. This pumping action generally works to oppose leakage out of the bearing. We examine how choices for the groove pattern can influence the key properties of the bearing. The focus is to understand the effect of the groove geometry on the pumping action. In particular the undesirable behavior caused by the low pressures created near the top/bottom ends of the bearing which, under many conditions, may result in the pressure becoming negative, relative to atmospheric pressure. Negative pressure can result in cavitation or, when it occurs near an air-oil interface, can cause air to be ingested and hence create bubbles. Any bubbles in the oil can corrupt the lubricating layer in the bearing and, as they are created and collapse, can cause significant undesirable vibrations. The negative pressures have therefore been identified as one of the key problems in design of hard disk drive bearings. We will use numerical computations and some analysis to show that by modifying the groove geometry we can reduce the negative pressure while retaining good stability characteristics

Silicon microstructures and microactuators for compact computer disk drives

Advances in VLSI and software technology have been the primary engines for the ongoing information revolution. But the steady stream of technical innovations in magnetic disk recording technology are also important factors contributing to the economic strengths of the computer and information industry. One important technology trend for the disk drive industry has been that of miniaturization. As this trend continues, future disk drives will have the same form factor as VLSIs, storing gigabytes of data. Silicon micromachining technology will play an important role in the fabrication of high-bandwidth servo-controlled microelectromechanical components for future super-compact disk drives. At UCLA and Caltech, for the past two years (1992-94) we have initiated a number of industry-supported joint research projects to develop microstructures and microactuators for future generation super compact magnetic recording rigid disk drives, including one to design and fabricate silicon read/write head microsuspensions with integrated electrical and mechanical interconnects, which target the next generation 30% form factor pico-sliders, and one for electromagnetic piggyback microactuators in super high-track-density applications, both of which utilize state-of-the-art silicon micromachining fabrication techniques