摘要:
Apparatus and method that incorporate bussed test access port interface into a system control interface for testing and controlling system logic boards in a manner that is fully compliant with the IEEE 1149.1 standard, while conserving system controller card signals. The apparatus incorporates six signals per interface, which includes the five standard signals as defined by IEEE 1149.1 standard plus a maintenance enable (ME) signal. Four of the standard signals, TCK, TMS, TDI and TRST* are bussed among multiple system logic boards, while the ME signals and the TDO signals are connected in a point-to-point manner between the system controller card and system logic boards. Instruction and data on the TCK, TMS, TDI, and TRST* signals are simultaneously bussed to all system logic boards. These four signals are received by each system logic board through an interface enable circuit, controlled by the ME signal line. If the instructions or data are intended for a specific system logic board, its corresponding ME signal line will be enabled to permit the passage of these signals and the resulting TDO signal through the interface enable circuit. This arrangement permits the incorporation of a bussed TAP interface into a system control interface for testing and controlling system logic boards that comply fully with the IEEE 1149.1 standard, while conserving the system controller card backplane pins dedicated to TAP signals, to two pins per system logic board plus four pins for the bussed TAP interface.
摘要:
A method and system for optimizing shift operations by reducing the computational overhead and the number of full scan path shifts associated with accessing and modifying data on a rotating scan path image are disclosed. The system further simplifies the construction of a scan path image by inserting a programmable number of leading and trailing bits around a selected string of data bits. The system manipulates and constructs a scan path image without having to shift or prepare the entire scan path image in memory. Specifically, the system comprises a master controller having a lead bypass module, a trail bypass module, a first shift module, a second shift module, a select module and a shift control module. Collectively, these modules comprise the necessary hardware for executing a plurality of shift optimization functions which include lead and trail bypass insertion, non-destructive read, field isolation, field insertion, bit order reversion, bit rotation and simultaneous read and write operation. The system further incorporates shift access windows and status registers for implementing shift operations without system calls.
摘要:
A common peripheral device interface module is disclosed for use with the Unix (Unix is a trademark of AT&T) operating system which is flexible enough to support many types of disk or tape device drivers. A common disk module (CDM) is included. The CDM contains high level disk operation commands which may be used for common reference to each disk driver on the system. Routines within the CDM are accessed by the Unix system call interface through a series of operating system entry points. Additional routines are included with the pre-existing Unix operating system Disk I/O Subsystem to improve interfacing between this subsystem and the CDM. A common tape module (CTM) is used to perform high level tape operation routines. The Unix system call interface communicates with the CTM through a group of operating system entry points. Because there is no Unix operating system tape I/O subsystem, the CTM completely implements a tape I/O subsystem. To provide hardware portability, the CTM is configured to call a group of low level routines which have been incorporated into a device driver. Because of the large number of possible root disk device drives, the root disk device driver can be dynamically selected for the Unix operating system. Each controller which is resident within the system checks in with the operating system. The controller which checks in first with the operating system is used for booting up the system. Each controller which checks in is matched with an appropriate device driver. The matched device drivers are then used for disk I/O functions.
摘要:
Apparatus for implementing input/output (I/O) operations in a computer system operating under the control of a UNIX* operating system includes a dedicated communications processor in addition to the main or host processor. These two processors communicate via a shared memory which may be independently accessed by each processor. The functions performed by the terminal I/O driver and the line discipline modules are divided between the host and communications processors. The communications processor performs all canonical processing of the data received from the terminal I/O devices. It also maintains a data structure that indicates the instantaneous status of each terminal I/O device. Using this data structure, the communications processor is able to operate in a substantially interrupt-free environment, polling only those I/O devices that are indicated, in the status data structure, as needing service. A message facility in the shared memory controls communication between the processors. Each processor sends messages to the other through a dedicated circular queue. To receive a message, a processor examines the sending queue of the other processor. Response messages are sent back to the sending processor using the same message buffer as was used for the original message.*UNIX is a trademark of AT&T
摘要:
Method and system for routing a network packet received at a port within a network is provided. The method includes (a) generating an index value based on a destination identifier for the network packet; (b) generating one or more physical port numbers based on the index value generated in step (a); wherein each port number identifies a port for sending and receiving network packets; and (c) selecting one of the physical port numbers to route the network packet; wherein the port number is selected based on reaction selector signal that is generated from a partition key table based on a partition key value embedded in the network packet.
摘要:
A common peripheral device interface module is disclosed for use with Unix (Unix is a trademark of AT&T) operating system which is flexible enough to support many types of disk or tape device drivers. A common disk module (CDM) is included. The CDM contains high level disk operation commands which may be used for common reference to each disk driver on the system. Routines within the CDM are accessed by the Unix system call interface through a series of operating system entry points. Additional routines are included with the pre-existing Unix operating system Disk I/O Subsystem to improve interfacing between this subsystem and the CDM. A common tape module (CTM) is used to perform high level tape operation routines. The Unix system call interface communicates with the CTM through a group of operating system entry points. Because of the large number of possible root disk device drives, the root disk device driver can be dynamically selected for the Unix operating system. Each controller which is resident within the system checks in with the operating system. The controller which checks in first with the operating system is used for booting up the system. Each controller which checks in is matched with an appropriate device driver. The matched device drivers are then used for disk I/O functions.