Abstract: A computer system including a write protection circuit and a write poster is disclosed. The write protection circuit provides page description information to the computer system for controlling various operations. Illegal write operations as defined by the page description information are prevented from reaching a system bus and external cache. Internal cache invalidate operations may also be performed transparently to system operation. The write poster accepts write operations in zero wait states and assembles them into fewer more efficient writes to memory. A unique method and apparatus for programming a descriptor random access memory (RAM) is also provided.

Abstract: A low-profile, clip-on heat sink for computer chip packages that releasably engages the side of the package and method for cooling computer chips is disclosed. The sink comprises a contact pad attached to a set of beams. Flanges extend down from the outer edges of the beams. The sink is engaged to the package by the flanges which attach to the sides of the package. When the sink is engaged to the package, the contact pad contacts the computer chip. When the chip is operating, heat flows from the chip to the contact pad. Heat then flows from the contact pad to the beams where it dissipates into the ambient surroundings. The sink may be released from engagement by deforming the flanges.

Abstract: A device adapted for attachment to the side of a disc drive for mounting the disc drive into a computer consists of a rectangular body having a connector member on one end. The connector member is bent to enable it to resiliently move relative to the body. Grounding tabs disposed on the body are bent up from the body to enable them to resiliently move relative thereto, and their tips are bent down to facilitate smooth installation and removal of the disc drive. A protruding latch member and stopping flap are disposed on the connector end. A secondary stop is disposed on the end of the body opposite the connector member.

Abstract: A computer system includes a computer address modification system that is advantageously coupled in a bus network to selectively translate memory address data in 16K blocks and provide DMA addresses which may match the 16 K memory address blocks. The modification system includes a mapping RAM selectively providing translated addresses to enable addresses in a 16 megabyte extended address space. The modification system also includes a page register storing for each addressable 16K block of data for each DMA channel a page address within the extended address space.

Abstract: A disk drive system includes a disk drive controller system having separate head positioning and data transfer subsystems and supporting up to four disk drives, two of which may be removable and two of which may connect through a standard ST506 interface. The system provides a read and write protected cylinder for removably drive and a read only cylinder for removable drives which may store a unique serial number as well as other write protected data. Each removable disk drive may includes a register storing an identification code which may be used to control operation of the drive.

Abstract: A disk drive system includes a disk controller system having separate head positioning and data transfer subsystems and supporting up to four disk drives, two of which may be removable, portable drive units and two of which may connect through a standard ST506 interface. The removable disk drives incorporate a read and write protected data cylinder for storing information such as the maintenance history of the drive, and a read only cylinder for storing a unique serial number as well as other write protected data. The system also features a high capacity, high speed sector buffer which allows continuous transfers of data to or from noninterleaved sectors and supports concurrent disk and system accesses.

Abstract: A disk drive system includes a disk controller system having separate head positioning and data transfer subsystems and supporting up to four disk drives, two of which may be removable and two of which may connect through a standard ST506 interface. The system provides a read and write protected cylinder for removable drives, a read only cylinder for removable drives which may store a unique serial number as well as other write protected data, and a high capacity, high speed sector buffer which allows continuous transfers of data to or from noninterleaved sectors and supports concurrent disk and system accesses.The system provides communication between enhanced disk controllers and enhanced disk drives over a standard ST-506 interface whereby command and status signals greater in number than those normally transmitted over the dedicated lines of the ST-506 interface are communicated between the enhanced disk controller and enhanced disk drive.

Abstract: A disk drive system includes a disk controller system having separate head positioning and data transfer subsystems and supporting up to four disk drives, two of which may be removable and two of which may connect through a standard ST506 interface. The system provides a read and write protected cylinder for removable drives, a read only cylinder for removable drives which may store a unique serial number as well as other write protected data, and a high capacity, high speed sector buffer which allows continuous transfers of data to or from noninterleaved sectors and supports concurrent disk and system accesses.

Abstract: In a magnetic disk storage system incorporated in a removable, portable module for use in a microcomputer system, a hinged separator element having a plurality of angled surfaces is movable between first and second positions. In the first position, the disk storage system is in an operational state with magnetic transducers loaded onto the surfaces of rigid magnetic disks and a carriage which mounts cantilevered beams for the transducers being free to move radially relative to the disks. In the second position, carriage motion is inhibited by the separator element which engages the cantilevered beams to raise the transducers away from the surfaces of the disks and into unloaded positions.

Abstract: A computer system includes a computer address modification system that is advantageously coupled in a bus network to selectively translate memory address data in 16K blocks and provide DMA page addresses which may match the 16K memory address blocks. The modification system includes a mapping RAM selectively providing translated addresses to enable addresses in a 1 megabyte address space to be selectively mapped to a 16 megabyte extended address space. The modification system also includes a page register storing for each addressable 16K block of data for each DMA channel a page address within the extended address space.

Abstract: In a magnetic disk storage system, a hinged separator element having a plurality of angled surfaces is movable between first and second positions. In the first position, the disk storage system is in an operational state with magnetic transducers loaded onto the surfaces of rigid magnetic disks and a carriage which mounts cantilevered beams for the transducers being free to move radially relative to the disks. In the second position, carriage motion is inhibited by the separator element which engages the cantilevered beams to raise the transducers away from the surfaces of the disks and into unloaded positions. A spring loaded trigger member which normally engages the separator element to latch the separator element in either of the first and second positions is momentarily disengaged from the separator element to permit movement of the separator element from the first to the second position by the spring or from the second to the first positions in response to movement of the carriage.

Abstract: A computer system includes a computer address modification system that is advantageously coupled in a bus network to selectively translate memory address data in 16K blocks and provide DMA page addresses in 16K blocks which may match the 16K memory address blocks. The modification system includes a mapping RAM selectively providing translated addresses to enable addresses in a 16 megabyte extended address space. The modification system also includes a page register storing for each addressable 16K block of data for each DMA channel a page address within the extended address space.

Abstract: A portable hard disk drive module enclosing all of the operative components of the disk drive is removably received by a receptacle in a microcomputer system. The disk drive module and the receptacle each have an electrical connector and these connectors are coupled when the module is in an operating position within the receptacle. The connectors comprise the sole interface between the operative components of the disk drive and the remainder of the computer system. The receptacle includes a transport mechanism for moving the module from a load position to the operating position and from the operating position to a module unload position. Accordingly, movement of the module between these positions in the receptacle is completely under machine control.

Abstract: A "Winchester" type magnetic disk memory apparatus is disclosed that includes an air recirculation system in the clean chamber that assures positive pressure at all points of potential leakage. In conjunction with that feature, the head assembly positioning mechanism is located outside the clean chamber to provide substantial improvements in contamination control. Significant advantages in the manufacture and maintenance of the apparatus also result.

Abstract: In a magnetic disk drive in which a cantilevered arm for mounting a magnetic head slider assembly is pivoted to move the slider assembly between a loaded position adjacent a rigid magnetic disk and an unloaded position spaced apart from the disk, a mechanism is provided for limiting the extent of movement of the slider assembly relative to the arm to prevent damaging contact of the slider assembly with the disk when the arm is in the unloaded position and the disk drive is subjected to shock loads. The slider assembly is mounted in gimballed fashion at a free outer end of the arm by a flexure element having different portions secured to the arm and to the slider assembly and a gimballing protuberance engaging the arm.

Abstract: A carriage supporting at least one read/write head is displaceable by a rack and pinion drive toward and away from the axis of rotation of a magnetic disk. The carriage has a pair of rollers--one at the inner end of the carriage, the other at the outer end--in contact with a fixed precision guide. The rack is cantilevered from a flexure element projecting from the carriage and formed as an integral part of the carriage. The free end of the rack is resiliently biased so as to urge (i) the rack into firm, meshing engagement with the pinion and (ii) the carriage rollers into positive, preloaded engagement with the guide. The limits of carriage motion and spacing between rollers are such that the line of force between the rack and pinion is always intermediate the axes of the rollers so that the carriage is stable along the entire extent of its travel.The rack is secured to the flexure element with a single screw fastener whose axis is oriented perpendicular to the pinion axis.

Abstract: A mechanism is disclosed for latching the read/write heads of a magnetic disk memory in a parking zone. The mechanism permits the heads to operate in the read/write mode within small distances of the parking zone and requires no additional electrical power. The mechanism includes a spring pawl cantilevered from the head/arm assembly and a latch plate pivotally mounted on the disk memory housing. In the latched condition of the head/arm assembly, the tip of the pawl engages a small abutment surface on the latch plate which is spring biased to arrest the motion of the assembly. Unlatching is effected by actuating the head/arm assembly to overcome the bias of the latch plate spring.

Abstract: In a magnetic disk memory, a magnetic disk is driven by a DC motor having a permanent magnet rotor and a pair of stator windings sharing a common ground connection point. The windings are alternately energized from an electrical power source by a switching circuit which produces positive voltage pulses of predetermined duration across the windings. The negative emf induced in the windings between energizing pulses provides a source of regulated, negative DC voltage which may be used to power various components requiring such a supply.

Abstract: A flexible conductor strip is provided for connecting a pivotally mounted electrical element, such as the armature of a sector motor, to fixed terminals supplying control signals to the electrical element. The conductor strip includes an arcuate segment having end terminations for connection to the electrical element and to the control signal terminals. The arcuate segment is curved into a generally U-shaped configuration, thereby coinciding substantially with the surface of the frustum of an imaginary right circular cone whose axis extends substantially perpendicular to the pivot axis of the electrical element and whose vertex lies substantially on that pivot axis.