Technical data

Device Support on OpenVMS Systems
7.1 Recompiling and Relinking OpenVMS Device Drivers
source changes to customer-written drivers, see the OpenVMS Alpha Guide to
Upgrading Privileged-Code Applications.
7.2 Restriction: Parallel SCSI Support for Logical Unit Numbers
V7.2
OpenVMS supports up to eight Logical Unit Numbers (LUNs) per target ID on a
parallel SCSI bus.
The SCSI-2 standard is limited to eight LUNs, but the SCSI-3 standard recently
increased to 64 LUNs. The HSZ80 is the only supported device that implements
more than eight LUNs (it supports 32 LUNs per target ID). This feature cannot
be used in the current release of OpenVMS. LUN values on OpenVMS must be in
the range 0-7.
This restriction does not apply to Fibre Channel.
7.3 Selective Autoconfiguration Unsupported in Some SCSI
Configurations
V7.2
OpenVMS Alpha provides SYSMAN commands that allow system managers to
specify which devices will be autoconfigured. This can be specified permanently,
so that it is applied at each system boot or for the duration of a manual
autoconfiguration command, using the following qualifiers:
SYSMAN> IO SET/EXCLUDE=(device_name)
SYSMAN> IO AUTOCONFIGURE/EXCLUDE=(device_n ame) and/or /SELECT=(device_name)
These commands cannot be used selectively to autoconfigure SCSI device
names that include a port allocation class or device names that have an HSZ
allocation class. The commands also cannot be used for Fibre Channel devices.
This restriction applies to class-driver devices only (DK, MK, DG). Selective
autoconfiguration can be used for all SCSI and Fibre Channel port-driver devices
(PK, PG, and FG).
This restriction also applies to OpenVMS Version 7.1 systems that use port
allocation classes.
7.4 Changes to the IO$_DIAGNOSE Function
The following sections contain IO$_DIAGNOSE changes.
7.4.1 Change to S2DGB$L_32PHSTMO and S2DGB$L_64PHSTMO
V7.3
The legal values for S2DGB$L_32PHSTMO and S2DGB$L_64PHSTMO are now
0 to 65,535 [about 18 hours]. Previously the values were 0 to 300 [5 minutes].
7.4.2 IO$_DIAGNOSE Behavior Changes
V7.3
Appendix B of the OpenVMS I/O User’s Reference Manual for Version 7.2
formerly stated that the following values are ignored when S2DGB$V_TAGGED_
REQ is 1:
S2DGV$L_32PHSTMO
S2DGV$L_64PHSTMO
7–2 Device Support on OpenVMS Systems