rz(4)
Name
rz − SCSI disk interface
Syntax
VAX NCR 5380:
adapteruba0at nexus?
controllerscsi0at uba0csr 0x200c0080 vector szintr
diskrz0at scsi0drive 0
VAX DEC SII:
adapteribus0at nexus?
controllersii0at ibus?vector sii_intr
diskrz0at sii0drive 0
RISC DEC SII:
adapteribus0at nexus?
controllersii0at ibus?vector sii_intr
diskrz0at sii0drive 0
RISC DEC KZQ:
adapteruba0at nexus?
controllerkzq1at uba0csr 0761300 vector kzq_intr
diskrz8at kzq1drive 0
controllerkzq2at uba0csr 0761400 vector kzq_intr
diskrz16at kzq2drive 0
RISC NCR ASC:
adapteribus0at nexus?
controllerasc0at ibus?vector ascintr
diskrz0at asc0drive 0
Description
The rz driver is for all Digital SCSI disk drives.
The major/minor device number mapping that the S/CA software uses is different from the mappings for TZ and RZ devices in the /dev directory.
The S/CA software was written to support Logical Unit Numbers (LUNs), but the current ULTRIX release does not support LUNs. The number of bits required to identify a SCSI device with LUN support is greater than 8, so a 16-bit major/minor device number is not sufficient.
To minimize changes to the S/CA software and support utilities, the ULTRIX major/minor number definitions in the /dev directory are mapped by the CAM disk and tape drivers to the RZ/TZ kernel entry points expected by the CAM dev_t argument. The CAM common routines require that the CAM dev_t major/minor device number mapping be used when a dev_t argument is passed to them.
The minor number bits for RZ devices contained in the /dev directory are defined as follows:
bits 0-2 = partition number
bits 3-7 = unit number
(0-7 for devices on controller 0)
(8-15 for devices on controller 1)
(16-23 for devices on controller 2)
(24-31 for devices on controller 3)
bits 8-16 = major index
The bit definitions for the dev_t argument expected by the CAM common routines are as follows:
bits 0-3 = partition number (0-16)
bits 4-6 = LUN (0-7)
bits 7-9 = target ID (0-7)
bits 10-11 = controller number (0-3)
bits 12-16 - major index
The device special file names associated with rz disks are based on the following conventions. These conventions are closely associated with the minor number assigned to the disk. The standard device names begin with rz for the block special file and rrz for the raw (character) special file. Following the rz is the logical unit number and then a letter, a through h, to represent the partition. Throughout this reference page, the question mark (?) character represents the logical unit number in the name of the device special file. For example, rz?b could represent rz0b, rz1b, and so on.
The disk can be accessed through either the block special file or the character special file. The block special file accesses the disk using the file system’s normal buffering mechanism. Reads and writes to the block special file can specify any size. This avoids the need to limit data transfers to the size of physical disk records and to calculate offsets within disk records. The file system can break up large read and write requests into smaller fixed size transfers to the disk.
The character special file provides a raw interface that allows for direct transmission between the disk and the user’s read or write buffer. In contrast to the block special file, reads and writes to the raw interface must be done on full sectors only. For this reason, in raw I/O, counts must be a multiple of 512 bytes (a disk sector). In the same manner, seek calls must specify a multiple of 512 bytes. A single read or write to the raw interface results in exactly one I/O operation. Consequently raw I/O may be considerably more efficient for large transfers. Multiply buffered I/O operations are possible to any raw SCSI device. (See nbuf() for more information.)
For systems with SCSI disks, the first boot of the ULTRIX software after the system is powered on may take longer than expected. This delay is normal and is caused by the software spinning up the SCSI disk drives.
Disk Support
This driver handles all disk drives that can be connected to the SCSI bus. Consult the ULTRIX Software Product Description to determine which drives are supported for which CPU types and hardware configurations.
The starting location and length (in 512 byte sectors) of the disk partitions of each drive are shown in the following table. Partition sizes can be changed by chpt(.). For further information, see dkio(.).
RZ22 partitions
diskstartlength
rz?a032768
rz?b3276869664
rz?c0102431
rz?d00
rz?e00
rz?f00
rz?g00
rz?h00
RZ23 partitions
diskstartlength
rz?a032768
rz?b3276866690
rz?c0204864
rz?d9945835135
rz?e13459335135
rz?f16972835136
rz?g99458105406
rz?h13459370271
RZ23L partitions
diskstartlength
rz?a032768
rz?b3276866690
rz?c0237588
rz?d9945835135
rz?e13459335135
rz?f16972867860
rz?g99458138130
rz?h134593102995
RZ24 partitions
diskstartlength
rz?a032768
rz?b32768131072
rz?c0409792
rz?d16384081984
rz?e24582481984
rz?f32780881984
rz?g163840245952
rz?h00
RZ24L partitions
diskstartlength
rz?a032768
rz?b32768131072
rz?c0479350
rz?d163840105170
rz?e269101105170
rz?f374180105170
rz?g163840315510
rz?h00
RZ25 partitions
diskstartlength
rz?a032768
rz?b32768131072
rz?c0832527
rz?d163840222896
rz?e370093222896
rz?f576346222895
rz?g163840668687
rz?h00
RZ26 partititons
diskstartlength
rz?a032768
rz?b32768131072
rz?c02050860
rz?d163840629006
rz?e792846629006
rz?f1421852629008
rz?g163840819200
rz?h9830401067820
RZ55 partitions
diskstartlength
rz?a032768
rz?b32768131072
rz?c0649040
rz?d163840152446
rz?e316286152446
rz?f468732180308
rz?g163840485200
rz?h00
RZ56 partitions
diskstartlength
rz?a032768
rz?b32768131072
rz?c01299174
rz?d163840292530
rz?e456370292530
rz?f748900550274
rz?g163840567666
rz?h731506567668
RZ57 partitions
diskstartlength
rz?a032768
rz?b32768184320
rz?c01954050
rz?d831488299008
rz?e1130496299008
rz?f1429504524546
rz?g217088614400
rz?h8314881122562
RZ58 partitions
diskstartlength
rz?a032768
rz?b32768131072
rz?c02698061
rz?d163840844800
rz?e1008640844900
rz?f1853440844621
rz?g163840819200
rz?h9830401715021
RRD40/RRD42 (read only) partitions
diskstartlength
rz?a0(size varies per CD)
rz?b00
rz?c0(size varies per CD)
rz?d00
rz?e00
rz?f00
rz?g00
rz?h00
RX23 partitions
diskstartlength
rz?a02879
rz?b00
rz?c02879
rz?d00
rz?e00
rz?f00
rz?g00
rz?h00
RX26 partitions
diskstartlength
rz?a05759
rz?b00
rz?c05759
rz?d00
rz?e00
rz?f00
rz?g00
rz?h00
RX33 partitions
diskstartlength
rz?a02400
rz?b00
rz?c02400
rz?d00
rz?e00
rz?f00
rz?g00
rz?h00
Usually, the rz?a partition is used for the root file system and the rz?b partition as a paging area. The rz?c partition can be used for disk-to-disk copying when it maps the entire disk (as it does when the disk size is less than 2.16 Gbytes).
Files
/dev/rz???
/dev/rrz???