摘要:
The memory comprises a linear space and a buffered space, each page of the buffered space is divided in a number m+1 of buffers of equal capacity, with m buffers devoted to the storage of data and one control buffer divided into m control blocks. There is a fixed relationship between one buffer control block and one data buffer. The control blocks are devoted to the storage of buffer and message chaining information. The linear space comprises queue control blocks, with one queue control block per user. The messages are received by memory interface 22 from the source users and then are enqueued in link inbound queues (LIQ) which are dynamically built by taking buffers from the buffered space, chaining the buffers by writing buffer and message chaining information in the corresponding buffer control blocks and writing the queue head and queue tail addresses in the user queue control block. A centralized control means is designed to process enqueue, dequeue and release orders upon requests from a user selected by an arbitrating means. When a link inbound queue becomes not empty, the memory interface 22 sends a dequeue order request to the centralized control means, said request identifying the corresponding user queue control block. The message address is provided in response thereto with the identification of the queue control block of the destination user. Then, the memory interface 22 sends an enqueue request to the centralized control means, said request identifying the address of the message to be enqueued and the queue control block of the destination user. The processing of this enqueue request by the centralized control means causes the messages to be enqueued in an outbound queue from which it is transferred to the destination user, by memory interface 22.
摘要:
The subject distribution mechanism is used in a communication system comprising a plurality of interfaces, (10, 11 ans 12) with each interface connected to at least one user and able to receive and transmit information to said user(s) through information carrying means. It allows communications to be established between users selected by a central control unit (7) in a programmable way. The distribution mechanism comprises: in each interface, scheduling means responsive to a common timing signal having a period T, to divide the period into n slot periods having a slot number, n being the number of users connected to that interface to which the maximum number of users are connected, a configuration table (18) comprising n locations, each location assigned to a slot period, the central control unit writing in each location communication control information, said table being addressed by the slot numbers generated by the scheduling means to read and make available, the communication control information, distribution buffer means (20) comprising at least a first and a second part, each part having n addressable locations, addressed by means of addressing means responsive to the communication control information provided by the configuration table during each slot period to cause each interface involved in the to be established communications during that slot period, to write the information to be transmitted in one part of the distribution buffer and the information to be received by the interface to be read from the other part of the distribution buffer at addresses derived from the communication control information and the slot number generated by the scheduling means.
摘要:
This invention relates to a protocol implemented in a communication system for exchanging data and control messages between adapters to which are attached different users, and a shared memory subsystem comprising a depository storage, a manager of storage and a microprocessor. Such protocol enables the adapters to be the initiators of the transmission and reception of data by using the control lines that connect the manager of storage to all adapters in the same way as the data bus and the address bus. Moreover, the adapters slice the messages into data bursts to which are associated control words specifying the sizes, the owner and the position of the burst in the message. Consequently, those data bursts may be interleaved when transiting on the data bus without the intervention of the microprocessor for the routing, and they will be stored in or read from the depository storage according to the identification of the user in the control word. Therefore, only the shared memory needs to have a high capacity of storage, whereas the manager of storage and the adapters can operate with a reduced capacity of storage, and the time to send or to access a data burst is much more improved.
摘要:
The subject device manages the access to message queues in a memory (6) by an enqueuer 2 and a degiieuer 7 when the enqueuer has priority over the dequeuer. It solves the contention problem raised when the dequeuer dequeues the last message from a queue while the enqueuer is enqueuing a new one. A queue control block QCB and queue status bits E, A, D are assigned to each queue and stored in memories 20 and 22. Each time dequeuer 7 performs a dequeuing operation it sets its D bit (dequeuer active) before updating the queue head field in the QCB block. When the enqueuer performs an enqueuing operation it sets an abort bit A, if it founds the D bit active and E bit active indicating that the queue contains at least one message to warn the dequeuer that it has to abort its proces if it is dequeuing the last message from the queue.
摘要:
The arbitrating method is based on the classification of the users in different categories, and the assignment to all users of each category of an identical privilege level which characterizes the interruption capability of the users of the category, in that a task performed by a selected user of a category can only be interrupted for granting access to the resource to a user of a category having a highest privilege level. Also a normal preference level is assigned to each user of each category, which determines the selection order of the users of the category, the privilege level of the user category and the preference level of each user constituting the priority level of the user. A user selection is made by analyzing the priority levels of the users making requests for the resource and determining the user having the highest priority level. The access to the resource is granted to a selected user which is the user having the highest priority level. If at least one user which has a privilege level higher than the privilege level of the selected user, makes a request for the resource, the task of said selected user is interrupted and the so-interrupted user is assigned an interruption preference level which is higher than the normal preference levels of the users in the category. Then a new user is selected.
摘要:
The data re-alignment method and device to be used in the transmission of data from a plurality of source buffers (113) of the shared memory to a flip-flop target buffers (117) before they are transferred to different users that share the memory, each source buffer being organized in 2 n byte words and the target buffer being organized in 2 m byte words, where m is greater than n. To perform a memory read operation, the data read from different source buffers are transferred to a Buffer Interface Register (122) for the re-alignment to match the size of the bytes word of the target buffer. Therefore, after successive reading from the source buffer to write the data into the BIR, the BIR which houses (2 m + 2 n - 1) bytes may loop back the exceeding bytes which are from position (2 m + 1) to (2 m + 2 n - 1) to which are added the next 2 n bytes read from the source buffer while the first 2 m bytes are transferred to the target buffer (117). The mechanism enables to avoid useless steps during the reading, the writing and the transfer. A pointer management system is adapted to the method and the device of the present invention in order to manage the data byte content of each word of the source buffers by indicating its beginning and its ending, and to manage the BIR to enable to loop the exceeding bytes to the first position of the BIR to which are added the next bytes from the source buffer, while the first eight bytes are transferred to the target buffer (117).