> -----Original Message----- > From: linux-scsi-ow...@vger.kernel.org [mailto:linux-scsi- > ow...@vger.kernel.org] On Behalf Of Douglas Gilbert > Sent: Friday, 04 July, 2014 2:44 PM > To: Hannes Reinecke; James Bottomley > Cc: Christoph Hellwig; linux-scsi@vger.kernel.org > Subject: Re: [PATCH 1/2] Use sdev_scsi2lun for SCSI parallel drivers > > On 14-07-04 07:54 AM, Hannes Reinecke wrote: > > SCSI-2 defines only up to 256 LUNs with a flat namespace. > > My SCSI-2 draft (revision 10b from August 1989) only has > 3 bit LUNs placed in byte 1 of the command block, in the top > 3 bits. There are also things called LUNTARs and LUNTRNs > at the message level. > > 8 bit LUNs do ring a distant bell, perhaps after SCSI-2? > > Doug Gilbert
The hierarchical LUN structures have some limited size LUN subfields: * the peripheral device addressing method includes an 8-bit TARGET OR LUN subfield, which specifies an 8-bit LUN at the current level (if the BUS IDENTIFIER field is 0) * the logical unit addressing method has a 5-bit LUN subfield --- Rob Elliott HP Server Storage -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
