On 09/28/05 18:43, Andre Hedrick wrote: > I have a vested interest in the improvement of the Linux SCSI Core and > wider adoption and support for SATA II and SAS controllers with their > associated domains and transport. Us and other companies too. > Proving a better design with a migration path for integration is the key > for success; however, I am not the person to be the political voice in the Yes, _it is_ the key to success. > James is king of the hill, and is reasonable to a point. James also Which "hill" is the question. If he were reasonable, he'd understand that the two technologies _are_ completely different and distinct and he'd not try to shove HIS solution down my throat. Just as I do not shove my solution in his throat. The whole point is that MPT-based (IOP on package) solutions _do not_ need a Transport Layer, since that Transport Layer _is_ already present: in the firmware _and_ access to it is _firmware_ dependent. All the while open transport solutions (ours and apparently Broadcoms') _expose_ the whole infrastructure and _give_ you the chip as an interface to the interconnect. So you actually _need_ a transport management layer. Now that transport management layer sits _below_ SCSI Core and SCSI Core is _unaware_ of the transport. > follows a model of generalization v/s specific design. Argh, this is not > going to be an easy one to explain or back away from now. Erm, inclusive > API design is where I am wanting to go with this thought. You can have inclusive API design for chips like AIC-94xx and BCM8603, because they <see paragraph above>. MPT-based ones <see paragraph above> would also use inclusive design _for MPT-based chips_. > Have you and company considered the approach of mapping to a library of > sorts? Hmm, it is not a library. It is a layer, again, because of what the chip actually is, and because of what it implements. Take a look at the announcement text, I do give some description there and in the code the drivers/scsi/sas-class/README file describes the event/managment infrastructure. Also you can take a look at the code. http://linux.adaptec.com/sas/ What you'll see in the code is: hardware implementation (interconnect, SAM 4.15, 1.3) firmware implementation (interconnect, SDS, SAM 4.6, 1.3) LLDD (SAM, section 5, 6, 7) Transport Layer (SAM 4.15, SAS) SCSI Core (SAM section 4,5,8) Commmand Sets (SAM section 1) A very nice explanation in latest SAM4r03, section 4.15 The SCSI model for distributed communications. Now for MPT based solutions you have: LLDD (SAM, section 5, 6, 7) SCSI Core (SAM section 4,5,8) Commmand Sets (SAM section 1) You see? No Transport Layer between LLDD and SCSI Core! Why? Because all this work is done in FIRMWARE! That is, the LLDD exports the LUs right into SCSI Core, So in effect there is _no_ need for a software Transport Layer. Can we have a video/tele conference on this? Luben - : 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
