IBM 990 - Manual (Page 21)

Chapter 1. zSeries 990 overview 9
Up to 1024 ESCON channels
The high density ESCON feature (FC 2323) has 16 ports, of which 15 can be activated for
customer use. One port is always reserved as a spare, in the event of a failure of one of the
other ports.
This is not an orderable feature. The configuration tool will select the quantity of features
based upon the order quantity of ESCON FC2324 ports, distributing the ports across features
for high availability. After the first pair, ESCON FC2323 are installed in increments of one.
ESCON channels are available on a port basis in increments of four. The port quantity is
selected and LIC CC is shipped to activate the desired quantity of ports on the 16-port
ESCON FC2323. Each port utilizes a light emitting diode (LED) as the optical transceiver,
and supports use of a 62.5/125-micrometer multimode fiber optic cable terminated with a
small form factor, industry standard MT-RJ connector.
Up to 120 FICON Express channels
An increased number of FICON Express features per z990 leads the way in distinguishing
this server family, further setting it apart as enterprise class in terms of the number of
simultaneous I/O connections available for FICON Express features. z990 supports 60
FICON Express features to be plugged, providing a total of 120 available channels. This is a
25% growth over what was available on z900. These channels are available in long wave (LX)
and short wave (SX).
The FICON Express LX and SX channel cards have two ports. LX and SX ports are ordered
in increments of two. The maximum number of FICON Express cards is 60, installed in the
three I/O cages.
The same FICON Express channel card used for FICON channels is also used for FCP
channels. FCP channels are enabled on these cards as a microcode load with an FCP mode
of operation and CHPID type definition. As with FICON, FCP is available in long wavelength
(LX) and short wavelength (SX) operation, though the LX and SX cannot be intermixed on a
single card.
zSeries supports FCP channels, switches and FCP/SCSI devices with full fabric connectivity
under Linux on zSeries. Support for FCP devices means that z990 servers will be capable of
attaching to select FCP/SCSI devices, and may access these devices from Linux on zSeries.
This expanded attach ability means that customers have more choices for storage solutions,
or may have the ability to use existing storage devices, thus leveraging existing investments
and lowering total cost of ownership for their Linux implementation.
The 2 Gb capability on the FICON Express channel cards means that 2 Gb link speeds are
available for FCP channels as well.
The Fibre Channel Protocol (FCP) capability, supporting attachment to SCSI devices in Linux
environments, was made generally available in conjunction with IBM TotalStorage®
Enterprise Tape System 3590, IBM TotalStorage Enterprise Tape Drive 3592, and IBM
TotalStorage Enterprise Tape Library 3494. For VM guest mode, z/VM Version 4 Release 3 is
required to support Linux/FCP. When configured as a CHPID type FCP, FICON allows
concurrent patching of Licensed Internal Code without have to configure the channel off and
on.