SCSI(4) | Device Drivers Manual | SCSI(4) |
scsi
, scsibus
—
scsibus* at scsi?
atapibus* at atapi?
options SCSIDEBUG
options SCSIVERBOSE
scsi
driver is the top, machine-independent layer of
the two-layer software system that provides an interface for the
implementation of drivers to control various SCSI or ATAPI bus devices, and to
use different SCSI bus host adapters or EIDE controllers. SCSI bus is capable
of supporting a wide variety of peripherals, including hard disks, removable
disks, CD-ROMs, scanners, tape drives, and other miscellaneous high-speed
devices.
The bottom layer is composed of the drivers for individual EIDE or SCSI bus controller chips (e.g. NCR 5380), accessed through various host bus interfaces, including, but not limited to PCI, ISA, Sbus, TURBOchannel, and NuBus. These individual devices are referred to as “host adaptors” in SCSI terminology, because they connect the SCSI bus to the host computer.
When NetBSD probes the SCSI busses, it “attaches” any devices it finds to the appropriate drivers.
If no specific driver matches the device, then
scsi
attaches the device to the
uk(4) driver so that user level
SCSI ioctl(2) calls may still
be performed against the device. Currently, only
sd(4),
cd(4),
st(4), and
uk(4) can attach to an atapi
bus.
Please see the intro(4) manual page to see which SCSI bus host adaptors are supported by NetBSD on your computer system.
scsi
software supports some
NetBSD kernel
config(1) options. They are:
SCSIDEBUG
printf
() statements
that can be turned on by
ioctl(2).SCSIVERBOSE
scsi
software.All devices and the SCSI busses support boot time allocation so that an upper number of devices and controllers does not need to be configured.
The devices are either wired so they appear at a particular device unit number or counted so that they appear as the next available unused unit number.
To configure a driver in the kernel without wiring down the device use a config line similar to
ch* at scsibus? target ? lun ?
to include the ch(4) changer driver.
To wire down a unit use a config line similar to
ch1 at scsibus0 target 4 lun 0
to assign changer 1 as the changer with SCSI ID 4, logical unit 0, on bus 0. Individual SCSI busses can be wired down to specific controllers with a config line similar to
scsibus0 at ahc0
which assigns SCSI bus 0 to the first unit using the ahc(4) driver.
When you have a mixture of wired down and counted devices then the counting begins with the first non-wired down unit for a particular type. That is, if you have a disk wired down as
sd1 at scsibus0 target 1 lun 0
then the first non-wired disk shall come on line as sd2.
SCIOCRESET
SCIOCDEBUG
SCSIDEBUG
.SCIOCCOMMAND
SCIOCREPROBE
SCIOCIDENTIFY
SCIOCDECONFIG
SCSIDEBUG
, the
SCIOCDEBUG
ioctl(2) can be used to enable
various amounts of tracing information on any specific device. Devices not
being traced will not produce trace information. The four bits that make up
the debug level, each control certain types of debugging information.
Bit
0
Bit
1
Bit
2
Bit
3
scsi
system appeared in MACH 2.5 at TRW.
This man page was originally written by Julian Elischer ⟨julian@freebsd.org⟩ for FreeBSD and extensively modified by Erik Fair ⟨fair@NetBSD.org⟩ for NetBSD.
scsi
driver along a list of flags indicating which
particular bad behaviors the device exhibits (and that the driver should be
prepared to work around).
July 26, 2006 | NetBSD 9.4 |