Abstract: A method of eliminating stale information from a computer graphics buffer. The method facilitates switching from a fast clear mode to a non fast clear mode during the lifetime of a region of interest such as a window: A clear count value associated with a pixel is read and compared with a current clear count. If the counts are not equal, a replacement value is written into the pixel. The process may be repeated for each pixel in the region. Block transfer hardware and fast clear hardware may be used together to perform the procedure in a high-performance manner: A source region and a destination region for the block transfer operation are both set to the region of interest. As the block transfer proceeds, each pixel is written either with its own value or with a replacement value depending on whether the clear count for the pixel is current.

Abstract: A technique for performing clear operations in a region having a subregion. Responsive to a clear command: a current clear count for the region is left unchanged; a predetermined value is written into the pixels of the subregion; and the current clear count is written into pixel clear counts of the subregion. Prior to creating the subregion, clear commands may be handled according to a conventional fast clear technique. After creating the subregion and during the life of the subregion, clear commands may be handled according to the inventive technique. After the subregion is discontinued, clear commands may once again be handled according to the conventional technique. The inventive technique may be employed optionally depending on the percentage of the region's area occupied by the subregion.

Abstract: A tool-less rack mounting system includes a grooved bullet attached to a flange on the end of a slide rail assembly. The bullet protrudes through a clearance hole formed on a corner post of a rack. A hand-releasable clip engages the groove, retaining the bullet in the clearance hole and retaining the flange against the post. The clip may be mounted to a bracket, and the bracket may include features for securing equipment in the rack. A hinged cable management arm may be mounted to the post and to the slide rail assembly without using tools. A flange on one end of the arm includes a clearance hole opening into a channel. The channel engages a standoff mounted to one of the rails of the slide rail assembly. A flange on the other end of the arm may be retained against the post by the bullet and the hand-releasable clip.

Abstract: A cooling apparatus for stacked components. Heat generating components may be mounted on two sides of a first printed circuit board. A second circuit board may be stacked over the first circuit board with a thermally conductive frame disposed between the two boards. The frame includes a cross member thermally coupled to the heat generating component on the top side of the first circuit board. The heat generating component on the bottom side of the first circuit board is thermally coupled to one leg of a thermally-conductive strap. The strap has a second leg that is thermally coupled to one end of the thermally conductive frame and also to one end of a heat distribution member mounted adjacent the second circuit board. The apparatus functions to channel heat from the first board's top and bottom components to the heat distribution member via the thermally-conductive frame and the thermally-conductive strap.

Abstract: A computer enclosure has first and second removable access panels. The access panels may be locked shut by securing them both to a chassis at a single point with a locking device. When the locking device is removed, each access panel may be opened and removed independently of the other access panel. The first removable access panel has a first locking tab. The second removable access panel has a second locking tab. The first and second locking tabs do not overlap one another. When the first and second removable access panels are mounted to the chassis, the chassis restrains the first and second removable access panels from movement in first and second orthogonal directions. When the locking device is in place, the locking device restrains the first and second removable access panels from movement in a third orthogonal direction by securing the first and second locking tabs to the chassis.

Abstract: A dual-purpose computer according to the invention has a gravity-actuated switch mounted therein or thereon. The gravity-actuated switch is used to control the speed of a cooling fan for the computer. When the computer is operated in a horizontal orientation such as a typical rack-mounted server would be, the gravity actuated switch assumes a first state. When the computer is operated in a vertical orientation such as a typical desk side workstation would be, the gravity actuated switch assumes a second state. When the switch is in the first state, fan speed controller circuitry runs the fan at a first speed. When the switch is in the second state, fan speed controller circuitry runs the fan at a second speed. In one embodiment, the first speed is a higher speed intended to optimize reliability, and the second speed is a lower speed intended to minimize noise.

Abstract: A technique for filling a memory area that represents a rectangle. The rectangle or a first section thereof may be divided into i+j horizontal subsections. The i horizontal subsections may be filled in a first pass using i region fill processors. And the j horizontal subsections may be filled in a second pass using j region fill processors. A second section of the rectangle may be filled by dividing the second section into n vertical subsections having equal width and filling the n vertical subsections using n region fill processors.

Abstract: A tool-less latch mechanism for attaching a panel to an enclosure for electronic equipment such as a computer. A lever is mounted to a first enclosure component at a pivot point and is operable to move in a pivot plane. A pawl extends from the lever substantially orthogonal to the pivot plane, and an arcuate slot is fixed on a second enclosure component. When the lever pivots from an open to a closed position, engagement of the pawl with a first surface of the slot causes relative movement between the enclosure components in a first longitudinal direction. When the lever pivots from the closed to the open position, engagement of the pawl with a second surface of the slot causes relative movement between the enclosure components in an opposite longitudinal direction.

Abstract: A circuit card retention device includes a longitudinal retention bar hinge-mounted to a support member of a computer enclosure or chassis. First and second hand-releasable lock members are attached to the retention bar at either end. Each lock member includes a flexible stop. When the retention bar is in a retaining position, the flexible stops engage a substantially rigid surface of the enclosure or chassis, keeping the bar in the retaining position. The flexible stops may be disengaged from the rigid surface by application of finger pressure, allowing the retention bar to pivot from the retaining position to an open position.

Abstract: A compact retractable label assembly includes a flexible label tongue and a guide bracket for receiving the label tongue. The guide bracket is adapted to mount to the inside of an enclosure surface such that the label tongue may be pulled from a mouth of the bracket to the outside of the enclosure surface. The guide bracket has a curved profile so that the label tongue bends when it is pushed inside the enclosure. The bend in the excursion path of the label tongue preserves space inside the enclosure.

Abstract: A power module assembly for multi-chip printed circuit boards: A heat distribution plate has first and second fields of receptacles integrally formed therein. The receptacles are populated with first and second fields of thermally-conductive pins. A power module printed circuit board is mounted to the heat distribution plate and has first and second clearance holes formed therein. The first and second fields of pins protrude through the first and second clearance holes. A multi-chip printed circuit board may be mounted underneath the power module such that the thermally-conductive pins contact a surface of first and second supplied chips. The supplied chips are physically close to the power module, and thermal management for the supplied chips is provided by virtue of contact between the supplied chips and the thermally-conductive pins. Space on the multi-chip printed circuit board is conserved.

Abstract: A configurable enclosure covers a computer for use in an office setting and can be removed for use of the computer in a rack-mount setting. The enclosure may be constructed using one identical panel in two places. The two panels releasably engage opposite sides of the computer to form a shell assembly. The shell may be taller and wider than the computer to establish air cavities that are in fluid communication with ambient air for cooling purposes. The panels are releasably attached by hooks that engage holes on the computer. Resilient catches secure the panels once the hooks are engaged. The assembly may be placed on its side in a pedestal. Tabs on the back and protrusions on the sides of the assembly secure it in the pedestal. An access panel of the computer may be removed while leaving the panels of the shell assembly attached.

Abstract: A mounting adapter a peripheral device. A strip is adapted to fit across the top or bottom of the device transversely. First and second device engagement tabs engage holes on left and right sides of the device, and first and second chassis engagement tabs engage holes on left and right sides of a chassis opening. The chassis engagement tabs and one of the device engagement tabs are disposed on arms that can be moved elastically in the transverse direction to engage and disengage the tabs with their corresponding holes. The adapter can be fashioned from a unitary piece of metal, and adds only the thickness of the strip to the vertical dimension of the peripheral device.

Abstract: A low-profile circuit board mounting and connecting scheme employs a conductive standoff having a shoulder, a stem and a head. A circuit board to be mounted on the standoff defines a clearance hole opening into a channel. The clearance hole is sufficiently large to clear the head of the standoff, and the channel is sufficiently wide to clear the stem but not the shoulder. A conductive clip has two resilient prongs. The clip is mounted to the circuit board so that the prongs are disposed along either side of a portion of the channel. The prongs are able to move toward and away from each other in a plane that is parallel to the plane of the circuit board. The prongs engage the head to make an electrical connection when the stem is moved to the end of the channel.

Abstract: A method and apparatus for controlling access to a multi-bank memory system. Multiple bank/row activation requests are presented by processes or systems seeking access to the memory. One of the banks of the memory is selected to be the target of a next bank/row activation request. Then, one of the requests corresponding to the chosen bank is selected and issued as the next request. Requests may be conditionally and iteratively selected until one is found whose target row corresponds to a currently active row in the target bank.

Abstract: A latch assembly is operable to catch automatically and is releasable by hand. A component frame defines a clearance hole and a stop. A latch, also with a clearance hole, is mounted to the frame so that the clearance holes overlap. The latch is biased against the stop but is capable of pivoting away from the stop responsive to hand-applied pressure. A peg having a groove underneath a sloping top is mounted to a chassis or other surface against which the component frame is to be retained. As the component frame is lowered over the peg, an edge of the latch contacts the top of the peg, causing the latch to pivot so that the frame may be lowered into place. When the frame is in place, the latch pivots back and snaps into the groove.

Abstract: Frame buffer memory bandwidth is conserved by performing a depth comparison between colliding pixels at batch building time. If the incoming pixel fails the depth comparison, then it may be “tossed” and excluded from any batches currently under construction. The batch building process may then continue without the need for a batch flush responsive to the occurrence of the pixel collision. If the incoming pixel passes the depth comparison, then it may yet be possible to avoid flushing: The current rendering mode of the pipeline is determined. If the current rendering mode does not require read-modify-write operations, then the incoming pixel may be merged with the buffered pixel with which it collides. Merger of the two pixels may be accomplished by overwriting the buffered RGBA pixel components with those of the incoming pixel, but only those components corresponding to asserted bits in the incoming pixel's BEN.

Abstract: A buffer facilitates reordering of memory access commands in a memory access command stream so as to create column coherencies that may be exploited with burst-mode memory cycles. A multi-column data storage buffer is provided. Storage control circuitry stores data associated with a memory access command into the multi-column data storage buffer at a column that corresponds to at least one of the LSBs of the column address associated with the memory access command. Flush control circuitry flushes the data storage buffer, when required, in column order. Each entry in the data storage buffer is associated with a unique valid bit. At flush time, the flush control circuitry analyzes the valid bits to determine an appropriate burst type for executing the memory access commands represented by the flushed buffer contents. The flush control circuitry may indicate the determined burst type to memory controller hardware by means of a burst type flag. The data storage buffer may include multiple lines.

Abstract: A fire shield for mounting over air ventilation holes on the bottom of a computer chassis. The shield includes an offset for holding a fire-impenetrable surface away from the air ventilation holes. The surface blocks a path that passes through the ventilation holes and extends orthogonally outward from the computer chassis, thus preventing flaming particles that fall through the air holes from passing beyond the shield. The shield establishes an air cavity that is in fluid communication with the air holes and with ambient air for cooling purposes. It may be constructed of sheet metal with first and second folded portions serving to create the offset. Hooks along the first elongate fold engage the air holes. A clearance hole on the second elongate fold receives a fastener. The air cavity may vent to ambient air on either end of the shield between the two folds.

Abstract: A computer enclosure has first and second removable access panels. The access panels may be locked shut by securing them both to a chassis at a single point with a locking device. When the locking device is removed, each access panel may be opened and removed independently of the other access panel. The first removable access panel has a first locking tab. The second removable access panel has a second locking tab. The first and second locking tabs do not overlap one another. When the first and second removable access panels are mounted to the chassis, the chassis restrains the first and second removable access panels from movement in first and second orthogonal directions. When the locking device is in place, the locking device restrains the first and second removable access panels from movement in a third orthogonal direction by securing the first and second locking tabs to the chassis.