Abstract:
Two design variations which allow multiple processors to start up using a single ROM. In each design, a single, primary processor is allowed to perform a complete POST while the remaining, secondary processors are directed in the course of their POST to perform a more limited initialization sequence. At power on, the primary processor begins a normal POST, while the secondary processors are held until a vector is placed into a redirection vector location. Each secondary processor is then subsequently started, using its own initialization code located at the address indicated by the redirection vector. The first technique is applicable to general multiprocessor systems because the implementation of this design can be run either from external software or from an addition to the operating system of the particular machine on which it is being used. The second technique is more specifically oriented to a particular system, and includes the use of an identity register to differentiate between primary and secondary processors.
Abstract:
A low quiescent current voltage regulator particularly suited for providing current to the RTC/CMOS memory section of a notebook computer. The gate of the JFET is grounded, the drain connected to the main battery and the source connected to the RTC voltage input of the RTC/CMOS memory section. The JFET source voltage approaches the gate-source cutoff voltage of the JFET. This cutoff voltage is selected to be in the proper range for the RTC/CMOS memory section. A complete RTC voltage control circuit is configured to provide 5 volts from the system voltage when the computer is turned on, 3 to 5 volts from the JFET when the computer is turned off and the main battery is present and 3 volts from the RTC battery when the computer is turned off and the main battery is removed.
Abstract:
An arbiter which allows retried requests to have high priority in subsequent arbitrations by not changing priority on a granted, but aborted, access to the bus and yet prevents the aborted requestor from thrashing the bus by masking its bus request signal until the data is available. Further, should an access to main memory be retried, all bus requests except the one from the memory system are masked to provide the memory system the highest effective priority to allow any flushing operations to occur. The masking of the various bus requests allows the arbiter to control access to a PCI standard bus without requiring that specific signals be added. The arbiter further includes modified priority LRU techniques and provides a locking requestor with an additional, highest priority position if retried.
Abstract:
A method for improving SCSI controller operations by actively patching SCSI processor instructions. In a first case, tag values assigned to queues for tagged queue operation are a multiple of the SCSI processor jump instruction length. When reselected, the tag value is patched or overwritten as the least significant byte of the address of a jump instruction. The upper bytes point to the beginning of a jump table. Each entry in the jump table is a jump instruction to the sequence for a particular queue or thread. Thus simple entry is made to the desired thread without a conditional branch tree. In a second case, special SCSI operations are directly handled by the host device driver and the SCSI processor only performs conventional data transfers and similar operations. The device driver patches the message length of the SCSI processor code to an illegal value, so that an illegal instruction develops, prompting the host device driver to perform the operation at a register level. This approach allows removal of all special operation conditional branching from the SCSI processor, greatly speeding up operations.
Abstract:
The present invention includes two variations of an apparatus which generate a version of the IORC* bus signal that is supplied to the read strobe input of a floppy disk controller that is asserted at the appropriate time during verify cycles between the floppy disk controller and a DMA controller. These designs allow an 82077 floppy disk controller to operate properly in FIFO mode when it is being used with software that does not require generation of this signal. The designs include use of a PAL and certain bus signal inputs to generate a signal which is asserted at the appropriate times during verify transfers. This signal is combined with the regular IORC* bus signal to produce the signal that is provided to the read strobe input of the floppy disk controller.
Abstract:
An apparatus for performing Least Recently Used techniques for a four way set associative cache system which includes a random access memory (RAM) which stores the ways representing the least recently used (LRU), most recently used (MRU) and LRU+1. The MRU-1 is developed by XORing the other three LRU way information values. Processor or snoop operation is determined and the way use aging information valued is based on snooping or processor operations. For processor operations the accessed or to be accessed way is set as the MRU, while in snoop operations, the way being accessed is set as the LRU. The aging of the remaining ways is shuffled accordingly. This shuffling occurs each cycle but is only stored on processor cache hit, processor read cache miss and snoop hit operations.
Abstract:
A system utilizes one or more programmable logic arrays or gate arrays for regulating the commands available to a microprocessor, and intercepting certain of those commands according to predetermined citeria. The system selects and processes designated commands relating to the FORCE-A20 signal and CPU-RESET signal for a keyboard controller functionally attached to an INTEL 80286 or 80386 microprocessor. The system includes one or more programmable logic arrays or gate arrays for allowing all input commands to pass directly through to the keyboard controller except the command sequence relating to the FORCE-A20 signal or the CPU-RESET signal.
Abstract:
A method of selecting and representing time-varying data from a time-relational database management system by providing a unified view on a computer display screen. The data from a master record for a particular entity is displayed with a default video or character attribute, and is considered to be the current record. Accessing a history record for that entity causes the data for fields that differ from the corresponding fields of the current record to be overlaid on such current record fields but with a video or character attribute distinct from the default video or character attribute. The overlaid current record becomes a new current record for further overlays. Similarly, accessing a pending record causes the data for fields that differ from the corresponding fields of the current record to be overlaid on such current record fields but with a video or character attribute distinct from the default video or character attribute. A plurality of history or a plurality of pending records may be composited so that all of the changed fields for a set of records from the end of a defined time period can be overlaid on a current record at one time. Accessing an error record causes the data for fields that differ from the corresponding fields of the current record (current as of the date of the error record) to be overlaid on such current record fields but with a video or character attribute distinct from the default video or character attribute. Fields in the error record that are in error (whether changed or not from the current record data) are overlaid on the current record fields but with a video or character attribute distinct from both the default video or character attribute and the video or character attribute used to indicate changed fields in the error record.
Abstract:
A processing array including a plurality of processing elements; and an interconnection network connected to all of the processing elements for carrying data messages between the processing elements, wherein each of the processing elements of the plurality of processing elements includes a parity generating circuit for generating a parity bit for a first data message that is transmitted by that processing element over the interconnection network to another processing element among the plurality of processing elements; and a parity checking circuit for checking parity of a second data message as it is received by that processing element over the the interconnection network, the parity checking and parity generating circuits being separate from each other and enabling that processing element to generate parity for the first data message being sent by that processing element while simultaneously checking parity of the second message received by that processing element.