Abstract: A buffer facilitates reordering of incoming memory access commands so that the memory access commands may be associated automatically according to their row/bank addresses. The storage capacity in the buffer may be dynamically allocated among groups as needed. When the buffer is flushed, groups of memory access commands are selected for flushing whose row/bank addresses are associated, thereby creating page coherency in the flushed memory access commands. Batches of commands may be flushed from the buffer according to a sequence designed to minimize same-bank page changes in frame buffer memory devices. Good candidate groups for flushing may be chosen according to criteria based on the binary bank address for the group, the size of the group, and the age of the group. Groups may be partially flushed. If so, a subsequent flush operation may resume flushing a partially-flushed group when to do so would be more beneficial than flushing a different group chosen solely based on its bank address.

Abstract: An EMI cover for a media drive housing. The cover includes a conductive surface adapted to cover one end of the housing. Conductive flanges are disposed along the sides of the surface. A first flange hingingly engages the housing. A second flange catchingly engages the housing. Attachment and removal of the cover may be achieved without the use of fasteners or tools. Protrusions disposed along the periphery of the cover enhance EMI blocking characteristics of the cover. A raised section of one of the flanges may extend over a portion of the housing to form an EMI-efficient cable management port.

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: For networked client-server computer graphics systems, performance is improved by caching immediate mode graphics commands in the server host. Two types of immediate mode command packets are employed—a full-size packet type and a truncated packet type. The full-size packet type includes a cache code field, a table index field and a data field corresponding to the command. The truncated packet type includes only the cache code field and the table index field. For certain outgoing immediate mode commands, if it is determined on the client side that the command's data field has not previously been stored within the server host, then the client host sends a full-size packet type to the server host to indicate the command. The server host executes the command and stores the command's data field in its own memory for possible later use.

Abstract: A computer having configurable air vents. A louver assembly may be attached to the computer enclosure or removed therefrom so that the enclosure may be adapted to the environment in which it will be used. For a desktop or other office environment, the louver assembly may be attached to the computer enclosure. For an industrial or rack-mount setting, the louver assembly may be removed. The louver assembly may be mounted in a bezel, which itself may be removably attached to the computer enclosure. A catch on the louver assembly engages a corresponding hole or depression in the enclosure or bezel, forming a detent. The holding force of the detent may be overcome by pushing the louver assembly out of the enclosure or bezel by hand, but is sufficiently strong to hold the louver assembly in place during normal operation of the computer.

Abstract: A sliding rail assembly adjusts and adapts to fit various racks. An adjustable mounting flange on an end of the rail assembly translates along the axis of the rail so that the length of the rail assembly adjusts to fit racks having various depths. Hooks on the rail assembly may be used to hang the rail assembly on the rack while the rail assembly is being installed therein. The hooks are removable so that the rail assembly will fit racks having narrow widths. Mounting adapters enable the mounting flanges to mate with corner posts having round holes as well as those having square holes. Securing tabs engage front corner posts of the rack to prevent the rail and the computer enclosure from sliding out. To accommodate racks having various depths, the securing tabs may be mounted at more than one location on the side of the computer enclosure.

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 heat sink retaining bracket having a first surface for engaging a heat sink and a second surface for engaging a chassis wall or other substantially rigid support member. The first surface may include an opening having a rim around its periphery. The rim may be adapted to engaged the top and sides of the heat sink such that sideways and upward translational movements are restrained. Air may pass through the opening as it enters or exits the heat sink so that the cooling efficiency of the heat sink is not substantially impaired by the bracket. The second surface may be adapted to engaged the chassis wall or support member using a hook-and-slot arrangement and a fastener or fasteners. In one embodiment, the fastener or fasteners may be applied in a compression mode. In another embodiment, the fastener or fasteners may be applied in a tension mode.

Abstract: A three-sided computer peripheral mounting bracket has two opposing guide rail sides and a front side but has no back side. The two opposing guide rail sides are operable to engage a computer chassis to guide the bracket during insertion and removal therefrom and to support the bracket after insertion therein. Each of the two opposing guide rail sides includes indented surfaces that are indented inward relative to outside surfaces of the guide rail sides. Each of the indented surfaces defines a recess for receiving an isolation grommet through which a computer peripheral device may be coupled to the bracket. Due to its shape, the bracket may be formed from a single piece of sheet metal. A spacer rod may be engaged between the isolation grommets to help keep the bracket square when it is not populated with the computer peripheral device. The front side of the bracket may include place holders for storing mounting screws and may include a curved handle.

Abstract: An EMI gasket exhibits enhanced compliance in the direction orthogonal to the plane of the circuit board on which a chip or chip-and-socket assembly is mounted. Therefore, the gasket may be used with chips or chip-and-socket assemblies having a variety of heights. In an embodiment, a frame made from a sheet of metal has a planar portion with an opening formed therein. The opening is adapted to fit around a perimeter of an integrated circuit chip. The sheet of metal includes top and bottom planar surfaces. Top and bottom resilient conductive members are attached to the top and bottom planar surfaces, respectively.

Abstract: A modified aggressive precharge method and apparatus for controlling a DRAM or system of DRAMs. Groups of memory access commands are sent to a DRAM controller. A bank/row activate command indicator is associated with the beginning of each group, and a bank precharge command indicator is associated with the end of each group. Normally, the DRAM controller will close the bank/row corresponding to a group responsive to the bank precharge command indicator associated with the end of the group; but the DRAM controller may conditionally leave the bank/row open, as follows: The DRAM controller analyzes the command stream to determine whether first and second groups of memory access commands are directed to the same row and bank. If so, then the precharge command indicated at the end of the first group and the activate command indicated at the beginning of the second group are not executed. The effect is to leave the bank/row of the first group open so that the second group may access it without having to reopen it.

Abstract: A fastener assembly includes a threaded fastener having an axial shaft. A spring is disposed coaxially around the shaft and is capable of compression and expansion in the longitudinal direction defined by the shaft. First and second stops are disposed along the shaft. The spring is pre-compressed and is disposed between the stops so that its expansion is limited by the stops. One end of the spring is mechanically coupled to a work piece. When the fastener is turned, relative displacement develops between the shaft and the work piece. The displacement causes the spring to further compress as the work piece end of the spring and the second stop move away from one another. The force of the compressed spring is transferred to the work piece.

Abstract: An EMI-efficient system for mounting internal peripheral devices such as disk or tape drives inside a computer enclosure so that the drives may be removed and replaced easily. A drive bracket guide is mounted to a computer enclosure chassis, a peripheral device is mounted to a drive bracket, and the drive bracket is inserted into an opening of the drive bracket guide. A socket support disposed at the end of the bracket guide opposite the opening fixedly supports a socket in position for receiving a mating socket on the drive. A locking insertion/ejection mechanism is coupled to the bracket and facilitates engagement/disengagement of the two sockets in the rear of the assembly. The bracket guide may be integrally formed on side walls of a drive cage to reduce potential for leaks of electromagnetic energy from the enclosure and to facilitate the creation of numerous bracket guides in a stack arrangement for housing multiple drives.

Abstract: A magazine assembly containing numerous media units is disposed adjacent to a picker assembly. One of the two assemblies is normally stationary, while the other assembly is a traveling assembly. In either case, the two assemblies cooperate with one another to selectively provide the picker assembly with access to the media units that are stored in the magazine assembly. A motion reversal assembly is coupled to the normally stationary assembly and is engageable by the traveling assembly when it enters an end portion of its excursion path. When the motion reversal assembly is so engaged, it moves the normally stationary assembly in the direction opposite to that of the traveling assembly's movement. The effect is an apparent increase in the traveling assembly's available excursion length, which makes it possible for the picker assembly to access media slots that would otherwise be disposed in the dead spaces located on either end of the traveling assembly's excursion path.

Abstract: A computer enclosure rack mounting system employs standoff members attached to left and right rails of telescoping extension slides. A computer enclosure includes bearing surfaces that are adapted to receive the standoff members. To install the computer enclosure into the rack, the left and right rails are extended, and the computer enclosure is lowered toward the rails until the standoff members of the rails engage the bearing members so as to support the enclosure. After this has been done, the enclosure and rails are simply slid back into the rack. The rails need not be removed from the rack to install the enclosure, and the enclosure need not be mounted to the rails by means of screws or bolts. The enclosure may be easily removed from the rack by reversing the just-described procedure, and may be installed into a different slot or a different rack without removing or replacing the rails.

Abstract: An EMI containment assembly for an integrated circuit chip. A frame forms an eletrically conductive wall around the perimeter of the integrated circuit chip. The bottom of the frame makes an electrically conductive contact with a ground trace on the printed circuit board to which the chip is mounted. The top of the frame makes an electrically conductive contact with an electrically conductive heat removal assembly that is disposed over the top of the chip. An electrically conductive bolster plate is mounted on the side of the printed circuit board opposite the integrated circuit chip and is disposed beneath the chip. Because each component of the assembly is electrically conductive, the assembly creates an EMI cage around the integrated circuit chip. Because the frame does not cover the top of the chip, it does not interfere with a thermally conductive contact that is made between the top of the chip package and the heat removal assembly.

Abstract: A method and apparatus are disclosed for achieving improved mipmapped texture mapping performance in computer graphics systems. Page residence indicators obviate the need for address comparisons during texel accessing. A mipmap page number is generated for texture data of interest. A page residence bit is then selected responsive to the mipmap page number. If the page residence bit is in a first state, then the texture data is retrieved from a memory located within the graphics subsystem; but if the page residence bit is in a second state, then the texture data is retrieved from system memory. System-wide texture offset addressing obviates the constraints associated with fixed relative addressing schemes.

Abstract: A single logical screen display system includes a client process, a master server process and plural slave server processes. Each of the slave server processes runs on a separate remote computer system. The master server process maintains network connections with the client process and with each of the slave server processes. The client process issues single logical screen window system requests to the master server process. The master server process issues physical screen window system requests to the slave server processes. Each slave server process controls one of a plurality of physical display devices. The plural physical display devices comprise a composite display on which the single logical screen appears.

Abstract: A method of buffering graphics vertex commands adaptively. A minimally-formatted vertex values buffer is created. As vertex commands are received from application software, attribute values are stored in an attribute values buffer until a vertex coordinate command is received. Upon receipt of a vertex coordinate command, attribute values are copied from the attribute values buffer into the vertex values buffer. Whenever application software issues a vertex attribute command corresponding to an attribute type that is not currently reflected in the vertex values buffer format, the vertex values buffer is automatically reformatted to include the new attribute type. Thus, the vertex values buffer automatically adapts itself to the behavior of the application. Multiple primitives are buffered between flushes. First-call and subsequent-call versions of code are provided for vertex commands. At initialization, a dispatch table is populated with pointers to the first-call versions.

Abstract: A clear color and count are stored in a frame buffer controller and in a video controller. The image buffer is cleared by writing the clear color into a color bit field and the count into a count bit field of each pixel. For each frame drawn, the count bit field of each pixel modified is updated with the count stored in the frame buffer controller. The counts stored in the frame buffer controller and the video controller are incremented with each new frame. When the counts reach maximum, the process repeats. Each time a pixel is read, the pixel's color bit field is replaced with the stored clear color if the pixel's count bit field is not equal to the stored count. The color bit field and the count bit field may be part of the same word of frame buffer memory. Or, the count value may be stored in an alpha bit field in lieu of an alpha value.