NAME

rz − SCSI disk interface

SYNOPSIS

Digital AlphaServer 8200 and Digital AlphaServer 8400 Qlogic ISP1020:
 bus tlsb0 at nexus? 
 bus tiop0 at tlsb0 vector tioperror
 bus isp0 at ∗ vector ispintr
 controller scsi0 at ∗ vector scsiintr
 controller scsi1 at ∗ vector scsiintr Digital AlphaServer 8200 and Digital AlphaServer 8400 DEC KZMSA:
 bus tlsb0 at nexus? 
 bus tiop0 at tlsb0 vector tioperror
 bus xmi0 at tiop? vector xmierror
 bus xza0 at xmi?
 controller scsi0 at ∗ vector scsiintr
 controller scsi1 at ∗ vector scsiintr DEC 7000/10000 DEC KZMSA:
 bus lsb0 at nexus? 
 bus iop0 at lsb0 vector ioperror
 bus xmi0 at iop0 vector xmierror
 bus xza0 at xmi?
 controller scsi0 at ∗ vector scsiintr
 controller scsi1 at ∗ vector scsiintr DEC 4000 DEC SIOP:
 bus ibus0 at nexus? 
 bus lbus0 at ibus0
 bus siop0 at lbus0 slot 0 vector siopcointr
 controller scsi0 at ∗ vector scsiintr DEC 3000 NCR ASC:
 bus tc0 at nexus? 
 bus tcds0 at ∗ vector tcdsintr
 controller scsi0 at ∗ vector scsiintr
 controller scsi1 at ∗ vector scsiintr DEC 3000 DEC KZTSA:
 bus tc0 at nexus? 
 bus tza0 at ∗ vector kztsaintr
 controller scsi0 at ∗ vector scsiintr DEC PCI bus DEC KZPSA:
 bus pci0 at ∗
 bus pza0 at pci? vector pzaintr
 controller scsi0 at ∗ vector scsiintr DEC PCI bus NCR 810:
 bus pci0 at ∗
 bus psiop at pci? vector psiopintr
 controller scsi0 at ∗ vector scsiintr DEC PCI bus Qlogic ISP1020:
 bus pci0 at ∗
 bus isp0 at ∗ vector ispintr
 controller scsi0 at ∗ vector scsiintr DEC EISA bus Adaptec 1740:
 bus eisa0 at ∗
 bus aha0 at ∗ vector ahaintr
 controller scsi0 at ∗ vector scsiintr DEC PCI bus ITI 875:
 bus pci0 at ∗
 bus itpsa at pci? vector itpsaintr
 controller scsi0 at ∗ vector scsiintr PCI bus CMD/Acer ATAPI/IDE adapter:
  bus pci0 at ∗
   bus ata0 at ∗
   controller scsi0 at ata0 slot 0
   controller scsi1 at ata0 slot 1 PCI bus Cypress ATAPI/IDE adapter:
 bus pci0 at ∗
   bus ata0 at ∗
   bus ata1 at ∗
   controller scsi0 at ata0 slot 0
   controller scsi1 at ata1 slot 0 PCMCIA bus ATA/IDE disk card:
   bus pcmcia0 at ∗
   bus ata0 at pcmcia?
   controller scsi0 at ata0

DESCRIPTION

The rz driver is for all Digital Small Computer System Interface (SCSI) disk drives in addition to AT Attachment (ATA), AT Attachment Protocol Interface (ATAPI) CDroms, and Integrated Drive Electronics (IDE) disk drives. 

The following rules are used to determine the major and minor numbers that are associated with an rz type disk.  There is one major number used to represent rz disks.  The minor number is used to represent both the SCSI unit number and partition.  A disk partition refers to a designated portion of the physical disk.  To accomplish this, the 20-bit minor number is broken up into two parts.  The low six bits of the minor number specify a disk partition.  The partitions use a letter, a through h, as their name.  The next 14 bits of the minor number specify the SCSI unit number within a group of disks. 

The device special file names associated with rz disks are based on conventions that 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 device number and then a letter, a through h, that represents the partition.  Throughout this reference page, the question mark (?) character represents the logical device number in the name of the device special file.  For example, rz?b could represent rz0b, rz1b, and so on. 

The SCSI unit number can be calculated if the major and minor number of an rz disk is provided.  For example, for the device special file rrz6a, the major number is 8 and the minor number is 6144.  The partition is represented by the lower six bits of the number 6144.  The lower six bits are 0, which specifies the a partition.  The next four bits of the minor number 6144 specify the SCSI logical unit number (LUN), which is 0.  The next four bits of 6144 specify the target ID of 6.  The next six bits specify the SCSI bus number, which is 0.  Because 8 is the base major number, it represents the group of SCSI disks.  Putting all these pieces together reveals that the major/minor number pair 8/6144 refers to the a partition of SCSI unit 6. 

Note that devices connected via ATAPI/IDE interfaces use SCSI id 0 (for the ATA master unit) and scsi id 1 (for the ATA slave unit).  None of the other SCSI identifiers are used for these adapters. 

A 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.  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. 

For systems with SCSI disks, the first software boot 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 Software Product Description (SPD) to determine which drives are supported for which CPU types and hardware configurations. 

SCSI RAID Controllers are viewed in most cases as RZ-type disks.  There are some differences that should be taken into consideration when configuring a RAID device:

       •Currently, only sector sizes of 512 bytes are supported. 

       •Logical Volume sizes are not a fixed size as compared to other SCSI disk devices.  The size of the Logical Volume is configurable based on needs.  The DYNAMIC nature of Logical Volume sizes is dealt with by defining RAID devices as DYNAMIC.  Only partitions a, b, c, and g are defined.  If needed, the disklabel(8) command can be run to change and define partitions for RAID devices. 

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 because it maps the entire disk. 

The starting location and length (in 512-byte sectors) of the disk partitions of each drive are shown in the following tables.  Partition sizes can be changed by using the disklabel(8) command. 

RZ24L Partitions
DiskStartLength
rz?a040960
rz?b40960122880
rz?c0479350
rz?d163840105170
rz?e269010105170
rz?f374180105170
rz?g163840315510
rz?h00

RZ25 Partitions
DiskStartLength
rz?a0131072
rz?b131072262144
rz?c0832527
rz?d393216146437
rz?e539653146437
rz?f686090146437
rz?g393216439311
rz?h00

RZ25L and RZ25M Partitions
DiskStartLength
rz?a0131072
rz?b131072262144
rz?c01046206
rz?d393216217663
rz?e610879217663
rz?f828542217664
rz?g393216652990
rz?h0     0

RZ26, RZ26L, and RZ26N Partitions
DiskStartLength
rz?a0131072
rz?b131072262144
rz?c02050860
rz?d393216552548
rz?e945764552548
rz?f1498312552548
rz?g393216819200
rz?h1212416838444

RZ28, RZ28B, and RZ28M Partitions
DiskStartLength
rz?a0131072
rz?b131072401408
rz?c04110480
rz?d5324801191936
rz?e17244161191936
rz?f29163521194128
rz?g5324801787904
rz?h23203841790096

RZ29B Partitions
DiskStartLength
rz?a0131072
rz?b131072401408
rz?c08380080
rz?d5324802623488
rz?e31559682623488
rz?f57794562600624
rz?g5324803936256
rz?h44687363911344

RZ55 Partitions
DiskStartLength
rz?a0131072
rz?b131072262144
rz?c0649040
rz?d00
rz?e00
rz?f00
rz?g393216255824
rz?h00

RZ56 Partitions
DiskStartLength
rz?a0131072
rz?b131072262144
rz?c01299174
rz?d393216301986
rz?e695202301986
rz?f997188301986
rz?g393216819200
rz?h121241686758

RZ58 Partitions
DiskStartLength
rz?a0131072
rz?b131072262144
rz?c02698061
rz?d393216768281
rz?e1161497768282
rz?f1929779768282
rz?g393216819200
rz?h12124161485645

RZ73 Partitions
DiskStartLength
rz?a0131072
rz?b131072262144
rz?c03907911
rz?d3932161171565
rz?e15647811171565
rz?f27363461171565
rz?g393216819200
rz?h12124162695495

RZ74 Partitions
DiskStartLength
rz?a0131072
rz?b131072393216
rz?c06976375
rz?d5242882150400
rz?e26746882150400
rz?f48250882151287
rz?g5242883225600
rz?h37498883226487

HSZ10 and HSZ40 (RAID) Partitions
DiskStartLength
rz?a0131072
rz?b131072262144
rz?c0end of media
rz?d00
rz?e00
rz?f00
rz?g393216  end of media
rz?h00

RRD42, RRD43, and RRD44 (Read-Only) Partitions (CD-ROM)
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

RX23HD and RX26HD Partitions (High-Density)
DiskStartLength
rz?a02880
rz?b00
rz?c02880
rz?d00
rz?e00
rz?f00
rz?g00
rz?h00

RX23DD and RX26DD Partitions (Double-Density)
DiskStartLength
rz?a01440
rz?b00
rz?c01440
rz?d00
rz?e00
rz?f00
rz?g00
rz?h00

RX23SD and RX26SD Partitions (Single-Density)
DiskStartLength
rz?a0720
rz?b00
rz?c0720
rz?d00
rz?e00
rz?f00
rz?g00
rz?h00

RX26 Partitions (Extra-Density Floppy)
DiskStartLength
rz?a05760
rz?b00
rz?c05760
rz?d00
rz?e00
rz?f00
rz?g00
rz?h00

RX33 Partitions (Extra-Density)
DiskStartLength
rz?a02400
rz?b00
rz?c02400
rz?d00
rz?e00
rz?f00
rz?g00
rz?h00

RX33HD Partitions (High-Density)
DiskStartLength
rz?a01440
rz?b00
rz?c01440
rz?d00
rz?e00
rz?f00
rz?g00
rz?h00

RX33DD Partitions (Double-Density)
DiskStartLength
rz?a0800
rz?b00
rz?c0800
rz?d00
rz?e00
rz?f00
rz?g00
rz?h00

RX33SD Partitions (Single-Density)
DiskStartLength
rz?a0720
rz?b00
rz?c0720
rz?d00
rz?e00
rz?f00
rz?g00
rz?h00

EXAMPLES

The following example shows the configuration specification that you might have for a DEC 3000 Model 500 system with a PMAZC controller in slot 0 and KZTSA devices in slots 1 and 2:

bus tc0 at nexus?
bus tcds0 at tc0 slot 6 vector tcdsintr         # onboard scsi
bus tcds1 at tc0 slot 0 vector tcdsintr         # PMAZC in tc slot 0
bus tza0 at tc0 slot 1 vector kztsaintr         # KZTSA in tc slot 1
bus tza1 at tc0 slot 2 vector kztsaintr         # KZTSA in tc slot 2
controller scsi0 at tcds0 slot 0 vector scsiintr # Internal port
controller scsi1 at tcds0 slot 1 vector scsiintr # External port
controller scsi2 at tcds1 slot 0 vector scsiintr # A port
controller scsi3 at tcds1 slot 1 vector scsiintr # B port
controller scsi4 at tza0 slot 0 vector scsiintr
controller scsi5 at tza1 slot 0 vector scsiintr

FILES

/dev/rz???
/dev/rrz???
/etc/disktab

RELATED INFORMATION

atapi_ide(7), RAID(7), SCSI(7), tz(7), disklabel(8), MAKEDEV(8), uerf(8)