Adapter for transferring blocks of data having a variable length on a system bus

• Main Authors: BENAYOUN, ALAIN, LE PENNEC, JEAN-FRANCOIS, SICSIC, PATRICK, MICHEL, PATRICK
• Format: Patent
• Language: English; French; German
• Published: 21.12.1994
• Edition: 5
• Subjects: CALCULATING; COMPUTING; COUNTING; ELECTRIC DIGITAL DATA PROCESSING; PHYSICS

An adapter for transfering blocks of data of a variable size to at least one destination adapter, each of the adapters being plugged in a respective slot and connected to a main system bus being under control of a central backplane. In each adapter, the transmission of one block of data is provided by means of: means (100, 620) for reading the slot identification characterizing the physical location where said transmitting adapter was plugged, means for generating a REQUEST word to be transmitted to said central backplane card via the system bus in order to request the access to the system bus, said REQUEST word being characteristic of the slot identification which was previously read; means for detecting an ACK acknowledge word generated by said central backplane having processed all the REQUEST words which were generated by the different adapters connected to the bus, said ACK word characterizing a particular adapter which is granted the access to said system bus; means operative in response to the detection of said ACK acknowledge word giving the access to the bus, for generating a signalling word to be transmitted to a particular destination adapter which will actually receive said transmitted data, said signalling word comprising information characterizing the type of command which said transmitting adapter requests to said backplane card, the address of said particular adapter which will receive said transmitted data, the size of the block of said transmitted data, and the address of said transmitting adapter; means for successively transmitting the blocks of data after said SIGNALLING word, the signalling word being received and processed by said destination adapter which is to receive the data block having said particular size. In each adapter, the reception of one data block is provided by means of: means for monitoring the SIGNALLING word which is transmitted via said system bus; means for processing said SIGNALLING word further comprising means for decoding the address of the destination adapter in order to determine whether the block of data which will be transmitted through the bus is to be received by said adapter; and means for extracting the size of the block in said SIGNALLING word in order to determine the size of the storage location which will be used for storing said data block.