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reserved allegiance. In the ESA/390 architecture, a
relationship that is created in a controller between a
device and a channel path when a Sense Reserve
command is completed by the device. The allegiance
causes the control-unit to guarantee access (busy
status is not presented) to the device. Access is over
the set of channel paths that are associated with the
allegiance; access is for one or more channel programs,
until the allegiance ends.
RETAIN. See remote technical assistance information
network
S
SAM. See sequential access method .
SBCON. See Single-Byte Command Code Sets
Connection .
SCSI. See small computer system interface .
SCSI ID. A unique identifier assigned to a SCSI device
that is used in protocols on the SCSI interface to
identify or select the device. The number of data bits on
the SCSI bus determines the number of available SCSI
IDs. A wide interface has 16 bits, with 16 possible IDs.
A SCSI device is either an initiator or a target.
Seascape architecture. A storage system architecture
developed by IBM for open-systems servers and S/390
host systems. It provides storage solutions that integrate
software, storage management, and technology for disk,
tape, and optical storage.
sequential access method (SAM). A sequential
access method to find information.
self-timed interface (STI). An interface that has one
or more conductors that transmit information serially
between two interconnected units without requiring any
clock signals to recover the data. The interface performs
clock recovery independently on each serial data stream
and uses information in the data stream to determine
character boundaries and inter-conductor
synchronization.
server group. See Copy Services server group .
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.
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.
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.
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ESS Introduction and Planning
service boundary. Physical space on an ESS rack. It
consists of a bay that contains SCSI and ESCON host
adapter cards and the attached devices (DDMs). If a
single component in a service boundary is being
serviced, none of its components are available to the
ESS.
service-information message (SIM). A message sent
by a storage server to service personnel.
service processor. A dedicated processing unit used
to service a storage facility.
service support representative (SSR). Individuals or
a company that you have authorized to service your
ESS. This term also refers to a service provider, a
service representative, or an IBM service support
representative (SSR). An IBM SSR installs your ESS.
shared storage. Storage within a storage facility that
is configured such that multiple homogenous 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.
You need to design the programs to handle the effects
of concurrent access.
short wave. A technology that allows you to connect a
variety of communication protocols.
SIM. See service-information message .
simple network management protocol (SNMP). (1)
An SNMP Manager is part of a network administration
software product, such as Tivoli TME 10 Netview. (2)
SNMP permits you to define management information
base (MIB) extensions, or enterprise-specific MIBs. By
loading a MIB file on a manager station, you can
monitor the MIB objects. The SNMP Agent accesses
MIB objects when a request is received from an SNMP
Manager. (3) 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).
Single-Byte Command Code Sets Connection
(SBCON). The ANSI standard for the ESCON 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 targets and initiators
in a multi-drop 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 .
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