Specifications

and uses information in the data stream to determine
character boundaries and inter-conductor
synchronization.
sequential access. A mode of accessing data on a
medium in a manner that requires the storage device to
access consecutive storage locations on the medium.
sequential access method (SAM). An access method
for storing, deleting, or retrieving data in a continuous
sequence based on the logical order of the records in
the file.
serial storage architecture (SSA). An IBM standard
for a computer peripheral interface. The interface uses a
SCSI logical protocol over a serial interface that
configures attached targets and initiators in a ring
topology. See SSA adapter.
server. (1) A type of host that provides certain services
to other hosts that are referred to as clients. (2) A
functional unit that provides services to one or more
clients over a network.
service boundary. A category that identifies a group
of components that are unavailable for use when one of
the components of the group is being serviced. Service
boundaries are provided on the ESS, for example, in
each host bay and in each cluster.
service information message (SIM). A message sent
by a storage server to service personnel through an
S/390 operating system.
service personnel. A generalization referring to
individuals or companies authorized to service the ESS.
The terms “service provider”, “service representative”,
and “IBM service support representative (SSR)” refer to
types of service personnel. See service support
representative.
service processor. A dedicated processing unit used
to service a storage facility.
service support representative (SSR). Individuals or
a company authorized to service the ESS. This term
also refers to a service provider, a service
representative, or an IBM service support representative
(SSR). An IBM SSR installs the ESS.
shared storage. Storage within an ESS that is
configured so that multiple homogeneous or divergent
hosts can concurrently access the storage. The storage
has a uniform appearance to all hosts. The host
programs that access the storage must have a common
model for the information on a storage device. The
programs must be designed to handle the effects of
concurrent access.
shortwave laser adapter. A connector used between
host and ESS to support shortwave fibre-channel
communication.
SIM. See service-information message.
Simple Network Management Protocol (SNMP). In
the Internet suite of protocols, a network management
protocol that is used to monitor routers and attached
networks. SNMP is an application layer protocol.
Information on devices managed is defined and stored
in the application’s Management Information Base
(MIB). See management information base.
simplex volume. A volume that is not part of a
FlashCopy, XRC, or PPRC volume pair.
Single-Byte Command Code Sets Connection
(SBCON). The ANSI standard for the ESCON or
FICON I/O interface.
Small Computer System Interface (SCSI). (1) An
ANSI standard for a logical interface to computer
peripherals and for a computer peripheral interface. The
interface uses a SCSI logical protocol over an I/O
interface that configures attached initiators and targets
in a multidrop bus topology. (2) A standard hardware
interface that enables a variety of peripheral devices to
communicate with one another.
SMIT. See System Management Interface Tool.
SMP. See symmetric multi-processor.
SNMP. See simple network management protocol.
software transparency. Criteria applied to a
processing environment that states that changes do not
require modifications to the host software in order to
continue to provide an existing function.
spare. A disk drive on the ESS that can replace a
failed disk drive. A spare can be predesignated to allow
automatic dynamic sparing. Any data preexisting on a
disk drive that is invoked as a spare is destroyed by the
dynamic sparing copy process.
spatial reuse. A feature of serial storage architecture
that enables a device adapter loop to support many
simultaneous read/write operations. See serial storage
architecture.
Specialist. See IBM TotalStorage Enterprise Storage
Server Specialist.
SSA. See serial storage architecture.
SSA adapter. A physical adapter based on serial
storage architecture. SSA adapters connect disk drive
modules to ESS clusters. See serial storage
architecture.
SSID. See subsystem identifier.
SSR. See service support representative.
stacked status. In Enterprise Systems
Architecture/390, the condition when the control unit is
Glossary 199
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