Product manual

CDA 7 Hardware
77 A1 69UP Rev00 2-9
2.4 Directors and Cache
This section describes the CDA 7 directors and cache capacity.
The channel directors and cache manage the storage control functions. The disk
directors handle the data storage functions.
2.4.1 Ultra SCSI Channel Director
The Ultra SCSI director is a single card that occupies one slot on the CDA 7
backplane. Each SCSI director interfaces to the host channels via a SCSI adapter
connected to the opposite side of the backplane.
The SCSI director has four differential wide interfaces for connection to host
systems and one high speed path to cache. The SCSI director contains two
advanced microprocessors that process commands and data from the host and
manage access to cache. They support data transfer rates up to 40 MB/sec with a
host over each channel interface simultaneously. On each SCSI channel director,
data transfers from the host to cache occur as four concurrent operations. The
CDA 7 can contain two or four SCSI directors.
2.4.2 Fibre Channel Director
The Fibre channel director is a single card that occupies one slot on the CDA 7
blackplane. Each Fibre Channel director interfaces to the host channels via a Fibre
Channel adapter connected to the opposite side of the backplane.
These adapters provide the connectivity between the host channel and the Fibre
Channel directors (FC-0 layer of the Fibre Channel standard). Each adpater
provides transceiver connections for two Fibre Channel ports.
The Fibre Channel director supports a data transfer rate up to 100MB/sec with a
host over each channel interface simultaneously.
The CDA 7 can contain two Fibre Channel directors.
2.4.3 SRDF Remote Link Director
The Remote Link Director (RLD) is a 4-port serial channel director microcode
configured as the link between CDA 7 units in a CDA Remote Data Facility
(SRDF) configuration. CDA requires two RLDs when used in the SRDF for
GCOS 7 solution.