Date: Tue, 22 Feb 2000 10:23:14 -0700 From: "Kenneth D. Merry" <ken@kdm.org> To: Nanda Kumar <nanda@procsys.com> Cc: freebsd-scsi@FreeBSD.ORG Subject: Re: Help to write a SCSI block driver Message-ID: <20000222102314.A20290@panzer.kdm.org> In-Reply-To: <38B2653A.41C5@procsys.com>; from nanda@procsys.com on Tue, Feb 22, 2000 at 04:00:18PM %2B0530 References: <38B22C09.2B7A@procsys.com> <20000221235253.A16855@panzer.kdm.org> <38B2653A.41C5@procsys.com>
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On Tue, Feb 22, 2000 at 16:00:18 +0530, Nanda Kumar wrote: > > The card that i am using is a RAID adapter and the RAID functionality is > implemented in the firmware running on the adapter. Hence it can be > treated as a normal SCSI adapter as far as the driver is concerned. So i > think i can write the device driver as SCSI block device driver. Is > there any documentation available on how the SCSI block device driver > interacts with the system ? So I could put tape drives, CDROM drives, DVD drives, etc. on your controller and expect to access them normally? Does the RAID array appear as a disk on the SCSI bus? There are several documents describing the general design of the CAM subsystem. See the CAM specs here: > >Kenneth D. Merry wrote: > > Controllers that fall into the first category would probably be best > > written as HBA drivers under the CAM SCSI layer. General documentation on > > CAM is located here: > > > > http://www.t10.org/drafts.htm#SWLAY Also, see Justin's presentation on CAM from USENIX '98: http://www.freebsd.org/~gibbs/ Some example SCSI drivers to look at are here: > > If you want to look at plain SCSI card drivers, there are plenty to choose > > from as well. Here are a few samples: > > > > Adaptec AIC 7xxx chips: src/sys/dev/aic7xxx > > Advansys chips: src/sys/dev/advansys > > Symbios/LSI chips: src/sys/dev/sym > > Adaptec 154x-type boards: src/sys/dev/aha If you've got more questions on the interaction between the CAM transport layer (XPT) and hardware adapter drivers (SIM layer), just send mail to this list. Ken -- Kenneth Merry ken@kdm.org To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-scsi" in the body of the message
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