scsi(4) [ultrix man page]
SCSI(4) Kernel Interfaces Manual SCSI(4) Name SCSI - Small Computer System Interconnect 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: o Winchester disks: RZ22, RZ23, RZ23L, RZ24, RZ55, RZ56, RZ57, RX23, RX26, RX33 o Magnetic tapes: TZ30, TZK50, TLZ04, TSZ05, TKZ08, TZK10 o Optical disks: RRD40, RRD42 Under the ULTRIX operating system, a SCSI device is referred to by its logical name. Logical names take the following form: nn# The nn argument is the two-character name; the number sign (#) represents the unit number. The two character names for SCSI devices are: rz - RZ22, RZ23, RZ23L, RZ24, RZ55, RZ56, RZ57, RX23, RX26, RX33, RRD40, RRD42 disks tz - TZ30, TZK50, TLZ04, TSZ05, TKZ08, and TZK10 tapes 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. 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. Restrictions The ULTRIX SCSI device driver does not operate with optical disks, other than the Digital-supplied devices. The SCSI driver attempts to support on a best effort basis, non-Digital-supplied winchester disks and magnetic tapes. The following notes apply to the driver's handling of non-Digital-supplied disks: o 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. o 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. o 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 The utility can also be used to modify the partition table on a RZxx disk. o The only logical unit number (LUN) supported for each target ID is 0. See Also rz(4), tz(4), chpt(8) SCSI(4)
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rz(4) Kernel Interfaces Manual rz(4) Name rz - SCSI disk interface Syntax VAX NCR 5380: adapter uba0 at nexus? controller scsi0 at uba0 csr 0x200c0080 vector szintr disk rz0 at scsi0 drive 0 VAX DEC SII: adapter ibus0 at nexus? controller sii0 at ibus? vector sii_intr disk rz0 at sii0 drive 0 RISC DEC SII: adapter ibus0 at nexus? controller sii0 at ibus? vector sii_intr disk rz0 at sii0 drive 0 RISC DEC KZQ: adapter uba0 at nexus? controller kzq0 at ibus? csr 0761300vector sii_intr disk rz0 at kzq0 drive 0 RISC NCR ASC: adapter ibus0 at nexus? controller asc0 at ibus? vector ascintr disk rz0 at asc0 drive 0 Description The driver is for all Digital SCSI disk drives. The following rules are used to determine the major and minor numbers that are associated with an type disk. There is one major number used to represent disks. The major number represents 32 disks. The minor number is used to represent the both the SCSI unit number and partition. A disk partition refers to a designated portion of the physical disk. To accomplish this, the 8-bit minor number is broken up into two parts. The low three bits of the minor number specify a disk partition. These three bits allow for the naming of eight parti- tions. The partitions have a letter, a through h, as their name. The upper five bits of the minor number specify the SCSI unit number within a group of 32 disks. The device special file names associated with 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 for the block special file and for the raw (character) special file. Following the 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 following examples illustrate how the SCSI unit number is calculated given the major and minor number of an disk. For the device spe- cial file rrz6a, the major number is 56 and the minor number is 48. The partition is represented by the lower three bits of the number 48. The lower three bits are 0, which specifies the ``a'' partition. The upper five bits of 48 specify the number 6. The major number is 56. Because 56 is the base major number, it represents the group of 32 disks. Putting all these pieces together reveals that the major/minor pair 56/48 refers to the ``a'' partition of SCSI unit 6. 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 buf- fer. 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, 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 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 For further information, see RZ22 partitions disk start length rz?a 0 32768 rz?b 32768 69664 rz?c 0 102431 rz?d 0 0 rz?e 0 0 rz?f 0 0 rz?g 0 0 rz?h 0 0 RZ23 partitions disk start length rz?a 0 32768 rz?b 32768 66690 rz?c 0 204864 rz?d 99458 35135 rz?e 134593 35135 rz?f 169728 35136 rz?g 99458 105406 rz?h 134593 70271 RZ23L partitions disk start length rz?a 0 32768 rz?b 32768 66690 rz?c 0 237588 rz?d 99458 35135 rz?e 134593 35135 rz?f 169728 67860 rz?g 99458 138130 rz?h 134593 102995 RZ24 partitions disk start length rz?a 0 32768 rz?b 32768 131072 rz?c 0 409792 rz?d 163840 81984 rz?e 245824 81984 rz?f 327808 81984 rz?g 163840 245952 rz?h 0 0 RZ55 partitions disk start length rz?a 0 32768 rz?b 32768 131072 rz?c 0 649040 rz?d 163840 152446 rz?e 316286 152446 rz?f 468732 180308 rz?g 163840 485200 rz?h 0 0 RZ56 partitions disk start length rz?a 0 32768 rz?b 32768 131072 rz?c 0 1299174 rz?d 163840 292530 rz?e 456370 292530 rz?f 748900 550273 rz?g 163840 1135334 rz?h 731506 567668 RZ57 partitions disk start length rz?a 0 32768 rz?b 32768 184320 rz?c 0 2025788 rz?d 831488 299008 rz?e 1130496 299008 rz?f 1429504 596284 rz?g 217088 614400 rz?h 831488 1194300 RRD40/RRD42 (read only) partitions disk start length rz?a 0 (size varies per CD) rz?b 0 0 rz?c 0 (size varies per CD) rz?d 0 0 rz?e 0 0 rz?f 0 0 rz?g 0 0 rz?h 0 0 RX23 partitions disk start length rz?a 0 2879 rz?b 0 0 rz?c 0 2879 rz?d 0 0 rz?e 0 0 rz?f 0 0 rz?g 0 0 rz?h 0 0 RX26 partitions disk start length rz?a 0 5759 rz?b 0 0 rz?c 0 5759 rz?d 0 0 rz?e 0 0 rz?f 0 0 rz?g 0 0 rz?h 0 0 RX33 partitions disk start length rz?a 0 2400 rz?b 0 0 rz?c 0 2400 rz?d 0 0 rz?e 0 0 rz?f 0 0 rz?g 0 0 rz?h 0 0 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 is used for disk- to-disk copying because it maps the entire disk. Files See Also nbuf(4), dkio(4), SCSI(4), chpt(8), MAKEDEV(8), uerf(8) rz(4)