Remove all SCSI devices for an IDE system?!

[Marc Fonvieille]

On Wed, Jul 18, 2007 at 04:48:14PM +0200, Ernst de Haan wrote:
> The Handbook, section 8.4:
> http://www.freebsd.org/doc/en_US.ISO8859-1/books/handbook/ 
> kernelconfig-config.html
> 
> reads:
> 
>    "SCSI controllers. Comment out any you do not have in your
>     system. If you have an IDE only system, you can remove these
>     altogether."
> 
> and:
> 
>    "SCSI peripherals. Again, comment out any you do not have, or
>     if you have only IDE hardware, you can remove them completely."
> 
> However, some IDE/SATA devices are interfaced through the SCSI  
> subsystem, IIRC. This seems to be supported by what is written a few  
> lines further down the text:
> 
>    # RAID controllers interfaced to the SCSI subsystem
>    device          amr        # AMI MegaRAID
>    device          arcmsr     # Areca SATA II RAID
> 
> Here a SATA2 RAID controller is listed as being linked to the SCSI  
> subsystem.
> 
> My suggestion is to fix and/or clarify this text.
>

I think you have to read carefully and completly this section before.
Here's a part of the related section:

---
 # SCSI Controllers
.
.
.
 device          ncv        # NCR 53C500
 device          nsp        # Workbit Ninja SCSI-3
 device          stg        # TMC 18C30/18C50

SCSI controllers. Comment out any you do not have in your system. If you
have an IDE only system, you can remove these altogether.

 # SCSI peripherals
 device          scbus      # SCSI bus (required for SCSI)
 device          ch         # SCSI media changers
 device          da         # Direct Access (disks)
 device          sa         # Sequential Access (tape etc)
 device          cd         # CD
 device          pass       # Passthrough device (direct SCSI access)
 device          ses        # SCSI Environmental Services (and SAF-TE)

 SCSI peripherals. Again, comment out any you do not have, or if you
 have only IDE hardware, you can remove them completely.

Note: The USB umass(4) driver and a few other drivers use the SCSI
subsystem even though they are not real SCSI devices. Therefore make
sure not to remove SCSI support, if any such drivers are included in the
kernel configuration.

# RAID controllers interfaced to the SCSI subsystem
device          amr        # AMI MegaRAID
device          arcmsr     # Areca SATA II RAID
device          asr        # DPT SmartRAID V, VI and Adaptec SCSI RAID
device          ciss       # Compaq Smart RAID 5*
device          dpt        # DPT Smartcache III, IV - See NOTES for
options
device          hptmv      # Highpoint RocketRAID 182x
device          rr232x     # Highpoint RocketRAID 232x
device          iir        # Intel Integrated RAID
device          ips        # IBM (Adaptec) ServeRAID
device          mly        # Mylex AcceleRAID/eXtremeRAID
device          twa        # 3ware 9000 series PATA/SATA RAID
---

It's clear: you can remove all SCSI controllers if you do not have any
SCSI devices.  You can remove SCSI peripherals if you do not have SCSI
devices *but* (it's the role of the Note) some devices are not SCSI
devices but will require you to keep the SCSI support.  This is the case
of "RAID controllers interfaced to the SCSI subsystem" mentioned just
after this note.

-- 
Marc