IBM 990 - Manual (Page 103)

Chapter 3. I/O system structure 91
7. The sum of IC, ICB-2, ICB-3, ICB-4, active ISC-3, and RPQ 8P2197 links supported on a
2084 server is limited to 64.
8. The maximum number of ICB-4 links on a 2084-A08 model is 12.
9. There are two feature codes for the ISC-3 card:
– Feature code 0217 is for the ISC Mother Card (ISC-M).
– Feature code 0218 is for the ISC Daughter Card (ISC-D).
One ISC Mother Card supports up to two ISC Daughter Cards, and each ISC Daughter
Card contains two ports. Port activation must be ordered using feature code 0219. RPQ
8P2197 is available to extend the distance of ISC-3 links to 20 km at 1Gbps. When RPQ
8P2197 is ordered, both ports (links) in the card are activated.
10.The maximum number of ISC-3 ports in peer mode is 48, and the maximum number in
compatibility mode is 32.
11.There are two types of “virtual” links that can be defined and that require CHPID numbers,
but do not have PCHID numbers:
– Internal Coupling (IC) links; each IC link pair requires two CHPID numbers.
– HiperSockets, also called Internal Queued Direct I/O (iQDIO). Up to 16 virtual LANs
can be defined, each one requiring a CHPID number.
12.Two ETR cards are automatically included in a server configuration if any coupling link I/O
feature (ISC-3, ICB-2, ICB-3 or ICB-4) is selected.
13.The sum of PCIXCC and PCICA cards on a z990 server is limited to eight.
14.The PCIXCC and PCICA features do not require CHPIDs but have PCHIDs.
15.The maximum number of PCICA cards per I/O cage is two.
At least one channel I/O feature (FICON Express or ESCON) or one Coupling Facility link I/O
feature (ISC-3, ICB-2, ICB-3, or ICB-4) must be present in a configuration.
The maximum number of configurable CHPIDs is 256 per Logical Channel Subsystem
(LCSS) and per operating system image.
Spanned and shared channels
The Multiple Image Facility (MIF) allows channels to be shared among multiple logical
partitions in a server:
MIF shared channels can be shared by logical partitions within a Logical Channel
Subsystem (LCSS).
MIF spanned channels can be shared by logical partitions within and across LCSSs.
Table 3-8 on page 92 shows which channel types can be defined as MIF shared and/or MIF
spanned channels on a z990 server.