NAME

disk, dsk, cdrom, rz − SCSI disk interface

SYNOPSIS

For each specific system, this information is located in the system configuration file in /sys/conf/<SYSTEM> and in /sys/conf/GENERIC

AlphaServer 8200 and AlphaServer 8400 Qlogic ISP1020:

bus tlsb0 at nexus?
bus tiop0 at tlsb0 vector tioperror
config_driver   isp

AlphaServer 8200 and AlphaServer 8400 DEC KZMSA:

bus tlsb0 at nexus?
bus tiop0 at tlsb0 vector tioperror
bus xmi0 at tiop? vector xmierror
config_driver   xza

DEC 7000/10000 DEC KZMSA:

bus lsb0 at nexus?
bus iop0 at lsb0 vector ioperror
bus xmi0 at iop0 vector xmierror
config_driver xza

DEC 4000 DEC SIOP:

bus ibus0 at nexus?
bus lbus0 at ibus0
config_driver siop

DEC 3000 NCR ASC:

bus tc0 at nexus?
config_driver tcds

DEC 3000 DEC KZTSA:

bus tc0 at nexus?
config_driver tza

DEC PCI bus DEC KZPSA:

bus pci0 at ∗
config_driver pza

DEC PCI bus NCR 810:

bus pci0 at ∗
config_driver psiop

DEC PCI bus Qlogic ISP1020:

bus pci0 at ∗
config_driver isp

DEC EISA bus Adeptec 1740:

bus eisa0 at ∗
config_driver aha

DESCRIPTION

The rz driver is for all HP Small Computer System Interface (SCSI) disk drives. 

There is one major number used to represent SCSI disks, pointing to the driver. The minor number (for scsi) is the SCSI driver’s logical ID (or LID).  Information for individual disks can be obtained using the hwmgr utility. 

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 SCSI disks are based on conventions that are closely associated with the minor number assigned to the disk. The standard device names begin with /dev/disk/dsk for the block special file and /dev/rdisk/dsk for the raw (character) special file. Following the dsk is the logical device number (decimal) 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, dsk?b could represent dsk0b, or dsk1b. 

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 SCSI-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 dsk?a partition is used for the root file system and the dsk?b partition as a paging area.  The dsk?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

RZ25 Partitions

RZ25L and RZ25M Partitions

RZ26, RZ26L, and RZ26N Partitions

RZ28, RZ28B, RZ28L, RZ28M. and RZ1B∗ Partitions

RZ29, RZ29B, RZ29L, RZ29M and RZ1C∗ Partitions

RZ55 Partitions

RZ56 Partitions

RZ58 Partitions

RZ73 Partitions

RZ74 Partitions

HSZ10, HSZ40, HSZ50, HSZ70  (RAID) Partitions

RRD42, RRD43, RRD44, RRD45, and RRD46(Read-Only) Partitions (CD-ROM)

RX23HD and RX26HD Partitions (High-Density)

RX23DD and RX26DD Partitions (Double-Density)

RX23SD and RX26SD Partitions (Single-Density)

RX26 Partitions (Extra-Density Floppy)

RX33 Partitions (Extra-Density)

RX33HD Partitions (High-Density)

RX33DD Partitions (Double-Density)

RX33SD Partitions (Single-Density)

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?
config_driver   tcds
config_driver   tza

The following system contains an NCR 810 controller for attaching CD-ROMS, KZPSA adapters for shared storage cluster connectivity, and KZPBA (qlogic) adapters:

bus pci0 at ∗
config_driver   psiop
config_driver   pza
config_driver   isp

FILES

/dev/disk/dsk??

/dev/rdisk/dsk??

/etc/disktab

/sys/conf/SYSTEM

SEE ALSO

Misc: RAID(7), SCSI(7), tz(7)

Commands: disklabel(8), hwmgr(8), dsfmgr(8) MAKEDEV(8), uerf(8)