International Business Machines Corporation

Hitachi Global Storage Technologies Netherlands B.v.

Hitachi Global Storage Technologies

Douglas Allan Kuchta

Paul Steven Severson

Douglas Howard Piltingsrud

Maurice L Hutson

Paul Jon Thomford

Karl Robert Erickson

James Aloysius Hagan

Ullal Vasant Nayak

Scott Raymond LaPree

Frederick Paul Benning

Steven L Maynard

Scott Peter Graves

Jon Edward Podolske

Janice Blue Ostrom

A method for making a magnetic disk, without chemical mechanical polishing to remove asperities, includes the steps of placing an annular-shaped element in a vacuum chamber, exposing a surface of the element to a beam of gas clusters while it is in the vacuum chamber, and thereafter applying a magnetic coating. The annular-shaped element may be a substrate, or it may be a substrate with a base coating such as glassy carbon or amorphous carbon. The substrate may be made of glass, preferably high quality fusion glass. The surface of the annular element may be textured by forming a sequence of concentric annular valleys, with plateaus being left between the valleys, before the magnetic coating is applied. A semiconductor wafer may also be smoothed by a beam of gas clusters to prepare the wafer for photolithography.

Disk, method for making it free of asperities utilizing a step of exposing a surface of the disk to a gas cluster ion beam and disk drive unit for using the disk

A method for texturing substrate surfaces and a substrate product, such as for computer disk drives. Microbump textured substrates are produced having a Rp value of about 20-200 &angst; and a ratio of Rmax:Rp of about 1.4 or less. In an exemplary embodiment, a microbump textured substrate is produced having colloidal particles on a surface thereof at a density of at least about 25 particles per 25 &mgr;m , wherein the surface topography includes a Rp value of about 20-200 &angst;, a micro-roughness Rq of about 10 &angst; or less, and a ratio of Rmax:Rp of about 1.4 or less. An exemplary method includes first providing a substrate surface having a surface micro-roughness Rq of about 10 &angst; or less and depositing colloidal particles on the surface to provide a Rp value of about 20-200 &angst; and a ratio of Rmax:Rp of about 1.4 or less. In a further exemplary embodiment, the method increases the micro-roughness Rq, but to a value that is still less than about 10 &angst; with Rmax:Rp still of about 1.4 or less.

Disk substrate with monosized microbumps

Disk substrates are polished in a process which uses a single load of the disks to a polishing apparatus and a single polishing slurry. Preferably, the process varies at least one polishing parameter at multiple stages to achieve both a reasonable rate of removal during one stage and a smooth finished surface during another stage. Preferably, a fine grit cerium oxide slurry is used, along with a polishing pad having surface characteristics intermediate those of relatively hard pads typically used for material removal, and of relatively soft pads typically used for fine finishing. The polisher operates at high pressure and speed during a material removal stage, and then reduces speed and pressure during a finishing stage to achieve a suitable surface finish, without removing and cleaning disks between the two stages.

Polishing process for glass or ceramic disks used in disk drive data storage devices

An electrical connection assembly for use in computer systems is disclosed. In the preferred embodiment, the computer system contains a backplane circuit card assembly for distribution of electrical signals to one or more pluggable modules. The modules are plugged into the backplane of the computer system without interrupting power to the computer system. The robust power connection is over-rated for the actual current and voltage delivered to the pluggable modules; and if any damage does occur at the point of initial contact, the connector surfaces are wiped beyond the initial contact point to the site of actual electrical contact which can occur at any place on a plurality of redundant surfaces. In this fashion, the connector assembly tolerates the arcing that occurs when the module is plugged into power grid on the backplane.

Robust power connection with redundant surfaces to allow arcing for hot-plug applications in computer systems

An electronic system contains a backplane circuit card which supplies power to various modules. Embedded power distribution planes each include one or more islands, each island being associated with a respective module. The island is electrically isolated from the body of the power plane except at a relatively small area, called the power ramp. The electronic current path from the power plane to the module goes through the power ramp and the island. Preferably, a pair of adjacent power planes at +48 VDC and 0 VDC are in the middle layers of the backplane with a ground plane on either side. Signal planes carrying circuit patterns for multiple data signals are deposited as additional layers on either side of the ground planes. The pair of power planes are nearly identical patterns, the differences being the location of power connections for the modules. In particular, the islands and power ramps are located in the same places on each power plane. This causes substantially equal but opposite current densities in the power planes, so that transients induced when a module is removed from or inserted into a powered-on system are significantly reduced. The exemplary embodiment is an intelligent redundant array of independent disks (RAID) storage server having concurrent maintenance capability.

Electronic circuit card having transient-tolerant distribution planes

An electronic system contains a backplane circuit card assembly for distribution of electrical signals among component devices. Power is distributed in embedded power planes, one of which is associated with ground. The backplane also contains multiple embedded ground planes. The circuit card assembly is divided by an axis into two halves, each half receiving and consuming approximately equal power. Electrical couplings for power sources and power planes in each half of the backplane are located symmetrically with respect to the axis. A row of ground vias along the axis couples the ground planes to the associated power plane. At all other locations on the backplane, the ground planes are electrically isolated from the associated power plane. Preferably, the backplane assembly comprises a pair of base cards, connected by a single smaller jumper card in which all ground vias are located. Each base card lies on a respective side of the axis, the jumper straddling the axis. The exemplary embodiment is an intelligent redundant array of independent disks (RAID) storage server having concurrent maintenance capability.

Electronic circuit card assembly having confined ground path return

An electronic system contains a backplane circuit card assembly for distribution of electrical signals to one or more modules. The card assembly includes a plurality of pluggably connected base cards, which provide redundant function. Preferably, two base cards in a single plane are connected by a single smaller parallel offset jumper card, the cards being coupled by pluggable connectors. The system preferably includes redundant power supply modules and redundant functional modules, which plug into the backplane from both sides. The modules connected to any one of the base cards provide minimum system functionality in the absence of the other card and its modules. Due to the redundant function, it is not only possible to replace any module, but is possible to replace a base card itself, while the system remains operational. The exemplary embodiment is an intelligent redundant array of independent disks (RAID) storage server having concurrent maintenance capability.

Multi-part concurrently maintainable electronic circuit card assembly

An enclosure for heat generating electronic components establishes an airflow path for cooling air. Air is forced through the enclosure by powered air movers, one of which is mounted at the air inlet to the enclosure, and the other of which is mounted at the outlet. Preferably only one air mover is used at a time. In the event of failure of the air mover being used, the remaining air mover begins operation. The total cooling airflow passes through both air movers, and thus the air movers may thus be said to be arranged in series with respect to the airflow. Because the air movers are mounted in series with respect to the airflow, the airflow pattern is substantially the same regardless of which air mover is currently operating. Thus, hot spots which may result when one fan in a fan bank fails are avoided. In the preferred embodiment, the enclosure houses a redundant array of independent disks (RAID) of a computer system. In an alternative embodiment, air movers arranged serially with the airflow can be used to provide additional cooling for severe operating conditions.

Growing community of inventors

Rochester, MN, United States of America

Douglas Allan Kuchta