This message is from the T13 list server.
On Fri, 05 Apr 2002 06:13:12 -0700, Pat LaVarre wrote: >This message is from the T13 list server. >Without disagreeing with the claim that pause vs. termination by >printed spec "should not" much matter, back in the real world I >too would enjoy hearing "under what conditions a device would >typically terminate a UDMA burst." I guess Jim and I should have been more clear on this... Either side of a DMA transfer (MW or U-DMA) can terminate the current DMA data burst for any reason at any time (as long as the protocol rules are followed). It should be noted that on x86 systems many DMA burst terminations are done by the host side because the host runs out of PCI bus bandwidth. This is why it is very important that readers of ATA/ATAPI-x must realize that DMA data burst sizes have nothing to do with device media block sizes. >And I can't remember if we here resolved the question of whether >occasionally terminating in order to trust less bits to any >single Crc was a good thing. (I know Atapi can ask for xFFFF >blocks per command, I think I remember 48 bit Ata can likewise.) If this is not in the "Signal Integrity" annex then maybe it should be there (as a recommendation). A 48-bit ATA command is able to transfer up to 65536 sectors (0x10000 sectors, about 33Mbyte of data). *** Hale Landis *** www.ata-atapi.com ***
