Hi, From: Christoph Hellwig <[EMAIL PROTECTED]> Subject: Re: FW: [openib-general] Minutes from DAPL BOF at OpenIB Workshop Date: Sun, 13 Feb 2005 15:29:06 +0100
> On Sun, Feb 13, 2005 at 03:25:24PM +0100, Christoph Hellwig wrote: > > On Sun, Feb 13, 2005 at 10:37:12AM +0200, Dan Bar Dov wrote: > > > > I don't know who "we" here is, but we as the kernel developer > > > > community certainly disagree. > > > > > > So how do you describe scsi mid layer? > > > Scsi mid layer is exaclty a unifying API that hides the specific hardware > > > device drivers from the upper layer abstractions. > > > The kdapl model is identical to the scsi model - a single in-kernel API > > > that hides different hardware specific implementations of RDMA. > > > > It's not really analogue. In SCSI the hardware (or at least the drivers) > > all speak the same protocol (in a few different revisions), and the scsi > > midlayer and upper level drivers implement most of that protocol. The > > LLDDs program the different hardware implementing this protocol. > > > > See the SAM-2 or SAM-3 documents for details. > > The right analogy for kDAPL in scsi land would be the CAM standard from > T10.org that tried to specifiy in-kernel interfaces for SCSI. While a > few Operating Systems tried to model their stack afer CAM (Digital Unix, > FreeBSD), it soon became clear that the standard isn't implementable 1:1 > in a real life system, was a hidrance in implementing clean and lean > driver and had no chance following the development of new SAM > substandards. I think there is a great difference between T10.org and DAT activity. In case of T10.org, I guess the development style was like spec. first and then implementations. This sometimes causes problems like you mentioned. But, the DAT activity is more like IETF style. Here, I mean DAT spec. people have been brushed up their documents getting feedbacks from implementation people. Thus, I believe the current kDAPL spec. can be a good start point of the discussion. -Masanori _______________________________________________ openib-general mailing list [email protected] http://openib.org/mailman/listinfo/openib-general To unsubscribe, please visit http://openib.org/mailman/listinfo/openib-general
