摘要:
The invention relates to multilevel interrupt device (10) using a common microprocessor interrupt signal (101) to process interrupt signals (INT1, . . . , INTN) received from N peripheral chips. This device (10) is connected to a microprocessor (100) and N peripheral chips (200,210,230) through data/address busses (108,110) and it is also connected to a memory (150) by an additional bus (112). An interrupt operation starts when any one of the peripheral chips activates an interrupt signal through OR gate (220) detected by the microprocessor. The invention avoids to involve the microprocessor in the determination of the interrupt requester except for the generation of a common start.sub.-- address decoded by logic (180) for starting interrupt operations and a common end.sub.-- address decoded by logic (190) for ending it. Owing to the start.sub.-- address and the interrupt signals (173,174) received, latch (170) generates a translated address to memory (150) through a multiplexer (160) to start the corresponding interrupt routine stored at this translated address. The activation of any one of the peripheral chips leads to the reading of the corresponding interrupt routine stored in the memory without requiring any action of the microprocessor. The number of interrupt routines depends on the possible combinations of the N interrupt signals.
摘要:
The invention provides an impedance adapter that automaticaly switches to impedances that match network transmit/receive lines impedances (105,106) by a controlled switching of various impedances mounted serially/parallely with connected transmitter/receiver (100,101). For a high speed adapter, a balanced transmitter/receiver is required for limiting crosstalk effect due to the high transmission rate. Transmit/Receive impedance adaptation networks (102-103) are composed of serial/parallel networks of resistors and relay contacts that are switched independently by magnetic coils of an impedance switching circuit (110) and having values conformable to the various network impedances imposed by different national regulations. By using the principle of double deviation voltage technique, a measuring circuit (108) detects upward and downward voltages (VA,VB), VB amplified by 2 to generate an analog signal VS (VS=VA-2VB) to a control logic circuit (109). This circuit (109) determines if the resistors value selected by the magnetic coils of said impedance switching circuit (110) is equal or not equal to the impedance of the network lines (106,105). Thus, it compares VS to a voltage Vref (25) to generate an output which selects and activates the correct magnetic coil for changing or keeping equal the resistors of the receive/transmit impedance network (102,103) currently connected to the network lines (105,106).
摘要:
A security system for preventing unauthorized use of a computer device. An extractable security piece includes an extractable main private key and a main PC public key. A PC security area which is a non-extractable part of the computer device includes a PC private key and an extractable main public key, which, together with the keys of the extractable security piece, constitute a Public Key Infrastructure. The extractable security piece and the PC security area include processing means for mutual authentication of the extractable security piece and the PC security area after the extractable security piece, which had been previously removed, has been reinserted in the computer device, thereby enabling the authorized user to access data stored in the computer device.
摘要:
The disclosed invention relates to a re-synchronization system that operates in a switching arrangement receiving a plurality of incoming data packets. The switching arrangement is made of an active switch card that transmits the incoming data packets and a backup switch card that may be re-activated by an operator after replacement. The re-synchronization system is implemented in each switch card. When the backup switch card is re-activated, both switch cards receive the incoming data packets and the system of the invention allows to re-synchronized both switch cards by controlling the transmission of the incoming data packets out of each switch card until the same data packets are transmitted. The re-synchronization system further comprise storage for storing the incoming data packets and detector for detecting a re-synchronization information among the incoming data packets.
摘要:
An improved data transmission system including multiple local area networks (LANs) coupled by a hub that further includes multiple LAN adapters coupled to the LANs, and an asynchronous transfer mode (ATM) crossbar switch coupling all LAN adapters. LAN data frames are converted into concatenated slots of an identical size and transmitted through the ATM crossbar switch. At least the requesting LAN adapter coupled to the LAN to transmit LAN data frame includes a serial communication controller (SCC) that converts a received LAN data frame into serial data. The SCC also includes a means for converting serial data to LAN data frames.
摘要:
A file manager (and method) provided for locating a file identified by a path referring to a logical unit and an identifier, includes a table associating the file with a priority list of physical units. The file manager can be incorporated into the controller of peripheral devices in a computer system or an operating system of the computer system.
摘要:
Data transmission system comprising a plurality of Local Area Networks (LANs) (10-1 to 10-4) interconnected by a hub (12) including the same plurality of LAN adapters (16-1 to 16-4) respectively connected to the LANs and a packet switch (14) interconnecting all LAN adapters wherein a packet transmitted by any adapter to the packet switch includes a header containing at least the address of the adapter to which the packet is forwarded. At each cross point is located a memory block for storing any data packet received from the input port corresponding to the cross point and which is to be forwarded to the output port corresponding to the cross point. The packet switch is composed of N×N identical packet switch modules with each of the packet switch modules being associated with m input ports and m output ports and comprises a rank selector which is programmed to provide a rank k from 0 to N−1 to each column of N modules corresponding to the same output ports, this rank being provided to all memory blocks of the column in order to shift the physical address of each output port in the column by an offset of k×m.
摘要:
A method and apparatus for an isochronous traffic of Asynchronous Transfer Mode (ATM) cells in a ring network having at least two stations (101,102) and a ring server (001). The communication within the ring is based on specific isochronous control and data cells. The control cell contains a cell header, sequence number, type of command and parameter fields. The data cell contains a header and a payload divided into N m-bit slots. The isochronous data cells are shared by a plurality of stations on the ring by allocating corresponding slotlist whose identification is carried in the parameter field. Furthermore, the server provides for each station's communication link a transmit identifier in the header associated to a reference in a list of allocated slots for transmission and a receive identifier associated to a reference in a list of allocated slots for reception. The implementation of two pairs of registers whose bits correspond to each byte of the isochronous data cell enables processing in real time transmission and reception of the isochronous data cells and to concatenate the bytes to be stored in a memory and to transmit transparently unmodified or substituted bytes on the ring.
摘要:
A conversion cache circuit, interfacing RISC busses to CISC peripheral circuits, provides master/slave Write and Read operations in a shared memory (130) and in the internal registers of the processor of said peripheral circuits (210). It enables RISC processor to Write and Read in the internal registers of the 8-bit processor in a salve operation while the 32-bit processor may perform the Write or Read operations to the shared memory through the conversion cache circuit in a master mode. The 32-bit processor may have access directly to the memory through its own direct access memory mechanism.
摘要:
The invention discloses a method of updating, in nodes on both ends of a secure link, the encryption key they share to encrypt and decrypt data. When having to transmit data from one of the nodes towards its peer remote node, a data base in the forwarding node, is first updated from the data to be transmitted. Then, encryption is performed and data transmitted to the peer remote node while a next-to-use encryption key is derived from the new contents of the data base. When received, data are decrypted with the current value of the encryption key and the peer remote node data base is updated identically from the received decrypted data after which a next-to-use encryption key is derived, thereby obtaining in the peer remote node, a next-to-use identical key. The data base is preferably the dictionary of a data compression/decompression system used simultaneously with encryption/decryption to transmit data over the secure link. While keys are frequently updated, for improved security, the invention does not require that key updates need to be actually distributed.