Digital Equipment EK-SFXXS-SG-003, Service Manual

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Glossary
ADAPTER
A module that connects one or more device controllers to the
system bus and hides many of the system bus requirements from the
controller. The KFQSA module is an Q–bus to DSSI bus adapter. The
KFMSA module is an XMI to DSSI bus adapter.
ALLOCATION CLASS
A numerical value assigned to the ISE to indicate
which system(s) on a cluster it will be served by.
BLOCK
The smallest data unit addressable on a disk. Also called a sector.
In DSSI ISEs, a block contains 512 bytes of customer data, EDC, ECC,
flags, and the block’s address header.
DECarray
A storage array that houses up to six storage enclosures and up
to two magazine tape ISEs (such as the TF857).
DEVICE NAME
A unique name given to each device by the VMS operating
system. The device name generally includes either the allocation class
and MSCP unit number assigned to the device (if the allocation class is
not zero), or the node name and MSCP unit number (if the allocation class
is zero).
DRVTST
A local program resident on the ISE. It is a comprehensive
hardware test used to verify ISE operation.
DSSI
Digital Storage System Interconnect. A DSA-based storage
interconnect used by the KFMSA adapter and the RF- and TF-series
integrated storage elements to transfer data and to communicate with
each other.
DSSI VAXcluster
Storage configuration where DSSI ISEs are shared
between two DSSI adapters and systems.
DUP
Diagnostic and utility protocol. A SYSAP-level protocol by which a
computer directs a storage device controller to run internal diagnostics
or utility functions. DUP is implemented as a class driver on the system
side, and a corresponding class server on the storage controller side.
EEPROM
Electrically erasable programmable read only memory. Used
by the KFMSA adapter to store configuration, manufacturing, and error
information in a nonvolatile location.
Glossary–1