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> problem... never ran into one > when working on a USB-ATA bridge > using UDMA (which did > support ATAPI commands). I'm not sure what you mean here. 1) Do you mean you translated Atapi commands to Ata or do you mean you passed thru Atapi commands unchanged from the Usb bus to the Ide bus? Only for the latter task does the bridge need a precise count of the bytes that crossed the bus. 2) WHICH Usb mass storage is key. Did you implement generic mass storage (bInterfaceClass SubClass Protocol x 08 06 50) or something less capable of plug 'n play? 3) WHICH Atapi commands between WHICH host and WHICH device is key. For example, were you blessed with an Atapi device that in Pio mode gave only a single DRQ INTRQ per non-block command? Pat LaVarre Subscribe/Unsubscribe instructions can be found at www.t13.org.
