descriptors or other commands initiating the data transfer the 1394 ohci specification describes the implementation of a minimum host controller implementation which consists of at least 12 descriptor based dma controllers or contexts for the following functions a dma controller not shown in fig1 is provided for each of the contexts identified above as noted descriptors generated by the software executing on the cpu 12 control the dna controllers these descriptors are temporarily stored within memory 22 for subsequent retrieval by the dma controllers upon request in the prior art the dma controllers retrieved the descriptors one at a time upon retrieval of the descriptors the dma controllers transfer data in accordance with variables contained within the descriptors the present invention seeks to obtain higher dma data transfer speed by reading or retrieving descriptors from memory 22 in large chunks versus the prior art method of reading descriptors from memory 22 one at a time further each prior art dma controller has a memory for storing corresponding descriptors however having a distinct memory in each dma controller increases the size and complexity of the 1394 ohci core 34 for example since there are at least twelve different contexts requiring twelve different descriptors at least 12 different memories within corresponding dma controllers are needed for each context the present invention seeks to unify descriptor storage and fetching operation therefore reducing the size and complexity of the 1394 ohci core 34 thus instead of having separate descriptor memory and separate logic gates for controlling access to the descriptor memory within each dma controller as in the prior art the present invention provides a single descriptor.