scsi.4

<B>Digital的Unix操作系统VAX 4.2源码</B>

.TH SCSI 4
.SH Name
SCSI \- Small Computer System Interconnect
.SH Description
The ULTRIX system interfaces to disk and tape devices through the
Small Computer System Interconnect (SCSI).
Initial ULTRIX 
SCSI
support is limited to the Digital-supplied mass storage devices.  The
following devices are fully supported on the ULTRIX system:
.NXR "SCSI device driver"
.NXR "Small Computer System Interconnect"
.NXR "device driver" "SCSI"
.IP \(bu 5
Winchester disks: RZ22, RZ23, RZ23L, RZ24, RZ55, RZ56, RZ57, RX23, RX26, RX33
.IP \(bu 5
Magnetic tapes: TZ30, TZK50, TLZ04, TSZ05, TKZ08, TZK10
.IP \(bu 5
Optical disks: RRD40, RRD42
.PP
Under the ULTRIX operating system, a 
SCSI
device is referred to by its logical name.  Logical names take
the following form:
.EX
nn#
.EE
The
.I nn
argument is the two-character name; the number sign (#) represents
the unit number.  The two character names for 
SCSI
devices are:
.IP rz  4
-  RZ22, RZ23, RZ23L, RZ24, RZ55, RZ56, RZ57, RX23, RX26, RX33, RRD40, RRD42 disks
.IP tz  
-  TZ30, TZK50, TLZ04, TSZ05, TKZ08, and TZK10 tapes
.PP
The unit number is a combination of the 
SCSI
bus number, either 0, 1, ... and the device's target ID number.
The unit number is eight times the bus number plus the 
target ID.  For example, an RZ23 disk at target ID 3 on bus
0 would be referred to as rz3; a TZK50 tape at target ID 5 on the second
SCSI bus would be referred to as 13.
.PP
The 
SCSI
bus has eight possible target device IDs.  By default, one is allocated
to the system.  This allows for a maximum of seven target devices
connected to a 
SCSI
bus.
.SH Restrictions
.PP
The ULTRIX
SCSI
device driver does not operate with optical disks, other than the
Digital-supplied devices.
.PP
The 
SCSI
driver attempts to support on a best effort basis, 
non-Digital-supplied
winchester disks and magnetic tapes.
.PP
The following notes apply to the driver's handling of 
non-Digital-supplied disks:
.RS 3
.IP \(bu 4
These disks are assigned a device type of RZxx, 
instead of RZ22, RZ23, RZ23L,
RZ55, RZ56, RZ57, RX23, RX26, or RX33.  
The RZxx disks follow the same logical device naming
scheme as the Digital-supplied disks.
.IP \(bu 4
During the autoconfigure phase of the system startup, 
the driver prints
the contents of the 
SCSI
vendor ID, product ID, and the revision level fields of the inquiry data
return by the 
SCSI
device.
.IP \(bu 4
RZxx disks are assigned a default partition table. The
default table can be modified by editing the sz_rzxx_sizes[8] entry in
the file
.PN /usr/sys/data/scsi_data.c .
The
.PN chpt
utility can also be used to modify the partition table on a RZxx
disk.
.IP \(bu 4
The only logical unit number (LUN) supported for each target ID is 0.
.RE
.SH See Also
rz(4), tz(4), chpt(8)