This message is from the T13 list server.
> "Mcgrath, Jim" <[EMAIL PROTECTED]> 12/14/01 03:00PM >>> > ... > So for a host who understands commands there should be no issue. > So in Pat's case, he should be safe in transferring the extra byte > and having the host take case of it (i.e. the host has > to understand it is an SFF-8020 issue, > even using the USB or other interface, > which is reasonable to me since this is a command level, > not a transport level, issue). > ... I'm not caught up on all the traffic, in particular not all the tutorials that seem to have been kindly written precisely for my benefit, but I saw this ... Some (lots of?) hosts still thinks they are talking Scsi. All the other stuff is a port of the Scsi stuff. The more or less open source of Linux and Mac OS X explicitly express life this way: not Scsi stuff is a "subclass derived from" Scsi, dunno about Wintel. Some plug 'n play code uses info from inside the system to see how Scsi a device is or is not: rumour tells me FireWire devices can talk to some flavours of Windows without bothering to implement op x12 Inquiry (!!!). Other plug 'n play code issues problematic commands like op x12 Inquiry in order to discover what kind of device is connected. That code can't know a given device will respond creatively to odd byte counts until it is too late. Agreed the Ansi text tells a host & device how to cooperate well enough to never clock IN across the bus more than 1 SwDma/UDma, never more than 3 MwDma, bytes beyond what AtapiPio would move. Still looks to me - and to a number of people working in partnership with me - like UDma Out can clock OUT across the bus as many as maxX * 2 + 1 bytes more out than AtapiPio would move, whenever the receiver tries to cut the transfer short before the sender does, provided the sender didn't coincidentally delay for a turnaround, with maxX = 2 for UDma 33 and rising with burst rate. But maybe after I comprehend the tutorials presented here lately, I'll clue in to how wrong I am. Wish me well. Pat LaVarre Subscribe/Unsubscribe instructions can be found at www.t13.org.
