14
z990 Logical Channel SubSystems (LCSSs) and support for
greater than 15 Logical Partitions (LP)
In order to provide the increased channel connectivity
required to support the scalability of the z990, the z990
channel I/O SubSystem delivers a breakthrough in con-
nectivity, by providing up to 4 LCSS per CEC, each of
which can support up to 256 CHPIDs with exploitation soft-
ware installed. This support is provided in such a way that
is transparent to the programs operating in the logical par-
tition. Each Logical Channel SubSystem may have from 1
to 256 CHPIDs and may in turn be confi gured with 1 to 15
logical partitions. Each Logical Partition (LPAR) runs under
a single LCSS. As with previous zSeries servers, Multiple
Image Facility (MIF) channel sharing as well as all other
channel subsystem features are available to each Logical
Partition confi gured to each Logical Channel SubSystem.
Physical Channel IDs (PCHIDs) SubSystem
In order to accommodate the new support for up to 1024
CHPIDs introduced with the Logical Channel SubSystem
(LCSS) a new Physical Channel ID (PCHID) is being intro-
duced. The PCHID represents the physical location of an
I/O feature in the I/O cage. CHPID numbers are no longer
pre-assigned and it is now a customer responsibility to do
this assignment via IOCP/HCD. CHPID assignment is done
by associating a CHPID number with a physical location,
the PCHID. It is important to note that although it is pos-
sible to have LCSSs, there is still a single IOCDS to defi ne
the I/O subsystem. There is a new CHPID mapping tool
available to aid in the mapping of CHPIDs to PCHIDs. The
CHPID Mapping tool is available from Resource Link™, at
ibm.com/servers/resourcelink.
Up tp 30 Logical Partitions
Up to 256
CHPIDs
Up to 256
CHPIDs
LCSS0 LCSS1
Up to 256
CHPIDs
LCSS3
Up to 256
CHPIDs
LCSS2
Note: Crypto no longer requires a CHPID
Physical Channels (PCHIDs)
102 103 104 110 200 201 202 2B0 2C5
Partitions Partitions
LCSS0 LCSS1
12 52 EF4F 12 2F EF00 02
IOCP - IOCDS
HCD - HSA or IOCDS - HSA
CHPIDs CHPIDs