System for transferring data specified in a transaction request as a plurality of move transactions responsive to receipt of a target availability signal

DETAILED DESCRIPTION The present invention is a system and method for efficiently transporting blocks of data through a high speed, bus-like interconnect, where the burst transfer size supported by the interconnect is smaller than the size of the data blocks to be transported.
The invention provides a transmission protocol that allows initiator and target bridges, through which requesting and responding nodes, respectively, are coupled to the interconnect, to coordinate the transmission and receipt of large data blocks as a series of smaller burst transfers.
In particular, the protocol defines signals that are exchanged between the initiator bridge ("initiator") and the target bridge ("target").
The exchanged signals (1) indicate the data block size to the target, (2) indicate to the initiator the available buffer capacity at the target, (3) transmit the data block to the committed target buffers through the interconnect as a series of burst transfers, and (4) determine when the transfer has been completed.
In accordance with the present invention, on receipt of a read request, an initiator allocates a buffer for storing requested data, generates a modified read request ("readPlus") specifying the size of the data block requested and the location of the allocated buffer, launches the readPlus to the target through the high speed interconnect, and waits for a response from the target.
If the target supports data blocks that are smaller than the size specified by the initiator, it indicates the supported data block size to the initiator, which adjusts the specified block size accordingly and launches a new readPlus.
A target having sufficient capacity to accommodate the specified size, indicates to the initiator that the transaction can proceed, retrieves the requested data block, and transmits the retrieved data block to the initiator as a series of burst transfers.
When all burst transfers have been transmitted, the initiator forwards the data as a block to the requesting node.
On receipt of a write request, an initiator specifies the size of the data block to be written in a modified write request ("writePlus"), and launches the writePlus request to the target