HP Mainframe Connectivity Design Guide

XP configuration rules
Table 78 (page 116) lists the XP mainframe configuration rules.
Table 78 XP mainframe configuration rules
DescriptionRule number
The XP storage system must be configured to emulate an IBM CU for mainframe
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implementations. For a list of IBM CUs, see Table 72 (page 113).
The XP storage system must be configured to emulate IBM disk volumes. For a list of IBM volume
types, see Table 72 (page 113).
2
A maximum of 256 disk volumes per CU is supported.3
The storage system is logically partitioned into uniquely addressable LCUs. Each image appears
as an independent LCU, but all LCUs share a common set of hardware facilities. Each LCU is
configured with a maximum of 256 volumes.
4
Each volume in the LCU is assigned a unique two-digit hexadecimal unit address in the range
x'00' to x'FF'.
5
A combination of the LCU number and the unit/device address uniquely identifies a
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particular volume in the storage system.
The LCU is called the CUADD in the mainframe configuration file. The CUADD is a two-digit
hexadecimal value in the range x'00' though x'FF'. For example, LCU x'01' is the same as CUADD
x'01'.
7
A unique 4-digit hexadecimal device address in the range x'0000' to x'FFFF' is assigned to each
volume in the mainframe configuration. This device address is also referred to as a UCB.
8
A unique 4-digit hexadecimal CUNUMBER in the range x'0000' to x'FFFF' is assigned to each
LCU in the mainframe configuration. Typically, the starting device address or UCB is assigned as
the CU number.
9
A UNITADD is the starting address of the range of devices configured in the LCU.
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For example, if the LCU has 256 devices configured with the device addresses x'00' through
x'FF', then x'00' is the UNITADD.
The UNITADD parameter contains two fields: the first field is UNITADD, and the second field is a
decimal value describing the range of addresses in the LCU. For example, an LCU with 256
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devices and configured with the device addresses x'00' through x'FF' has a UNITADD parameter
of 00,256.
The LPAR uses a logical path to communicate with the LCU. This path includes the CHPID on the
mainframe, the FICON port on the CU, and any ports and directors in the path. There can be up
to eight logical paths from an LPAR to any LCU.
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The system programmer assigns one or more 4-digit hexadecimal SSIDs to your storage subsystem.
The SSID is assigned to a range of either 64 volumes or 256 volumes. In an XP storage system,
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the valid range for the SSID is x'0004' though x'FEFF'. HP recommends using one SSID per LCU,
with a range of 256 volumes per SSID.
XP configuration examples
This section provides examples of XP configurations with and without PAVs.
XP configuration without PAVs
An XP DASD array configured to provide 2,048 mainframe volumes requires a minimum of 8
LCUs, each with 256 device addresses.
Table 79 (page 117) provides an example of an XP configuration without PAVs. All numbers are
hexadecimal unless noted otherwise.
116 XP storage system rules