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Hitachi Universal Storage Platform V/VM User and Reference Guide
Front-End Directors and Host Channels
The Universal Storage Platform V and VM support all-mainframe, all-open-
system, and multiplatform configurations. The front-end directors (FEDs)
process the channel commands from the hosts and manage host access to
cache. In the mainframe environment, the front-end directors perform CKD-
to-FBA and FBA-to-CKD conversion for the data in cache.
Each front-end director feature (pair of boards) is composed of one type of
host channel interface: fibre-channel, FICON, or Extended Serial Adapter
(ExSA) (compatible with ESCON protocol). The channel interfaces on each
board can transfer data simultaneously and independently.
The FICON and fibre-channel FED features are available in shortwave
(multimode) and longwave (single mode) versions. When configured with
shortwave features, the USP V/VM can be located up to 500 meters (2750
feet) from the host. When configured with longwave features, the USP V/VM
can be located up to ten kilometers from the host(s).
• FICON. The FICON features provide data transfer speeds of up to 4 Gbps
and have 8 ports per feature (pair of boards).
Note: FICON data transmission rates vary according to configuration:
S/390 Parallel Enterprise Servers - Generation 5 (G5) and Generation 6
(G6) only support FICON at 1 Gbps.
z800 and z900 series hosts have the following possible configurations:
– FICON channel will operate at 1 Gbps ONLY.
– FICON EXPRESS channel transmission rates will vary according to
microcode release. If microcode is 3G or later, the channel will auto-
negotiate to set a 1-Gbps or 2-Gbps transmission rate. If microcode is
previous to 3G, the channel will operate at 1 Gbps ONLY.
For further information on FICON connectivity, refer to the Mainframe Host
Attachment and Operations Guide (MK-96RD645), or contact your Hitachi
Data Systems representative.
• ESCON. The ExSA features provide data transfer speeds of up to 17
MB/sec and have 8 ports per feature (pair of boards). Each ExSA channel
can be directly connected to a CHPID or a serial channel director. Shared
serial channels can be used for dynamic path switching. The USP V/VM also
supports the ESCON Extended Distance Feature (XDF).
• Fibre-Channel. The fibre-channel features provide data transfer speeds of
up to 4 Gbps and can have either 8 or 16 ports per feature (pair of
boards). The USP V/VM supports shortwave (multimode) and longwave
(single-mode) versions of fibre-channel ports on the same adapter board.
Note: Fiber-channel connectivity is also supported for IBM mainframe
attachment when host FICON channel paths are defined to operate in fiber-
channel protocol (FCP) mode.