On Mon, 2005-08-15 at 11:41 -0400, Luben Tuikov wrote: > Hmm, you've > "found an actual use for channel (exposing underlying physical discs > of raid devices)". > > I'm completely befuddled James. For RAID cards in the SCSI subsystem that export RAID devices as SCSI devices, there's a need of a standard way to get at the underlying devices (for DV, parameter setting or configuration). The idea is to expose these devices on a non zero channel. > What if we didn't have "channel" (SPI leftover) in the first place? > Or, if an LU is implemented as a RAID device, how do you find out its > individual disks? It's not a SPI leftover. It's used by HBA's that have two channels that genuinely share resources. Although most modern SCSI cards simply have two chips (and hence two separate HBAs) per channel, there are a few, of which the qlogic fc card is one, that still have this one chip per two channels model. > Is there a spec or standard that you're following in doing this? It's an OS abstraction, so no. James - : send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
