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S

S_ID

CONTEXT [Fibre Channel]

Source_ID. A three-byte field that shall contain the address identifier of the source Nx_Port.

SA

CONTEXT [Security]

Acronym for Security Association.

SAM

CONTEXT [SCSI]

Acronym for SCSI Architecture Model.

SAN 

CONTEXT [Fibre Channel] [Network] [Storage System] [iSCSI]

1. Acronym for storage area network. (This is the normal usage in SNIA documents.)
2. Acronym for Server Area Network which connects one or more servers.
3. Acronym for System Area Network for an interconnected set of system elements.

SAR

CONTEXT [Security]

Acronym for Security Assurance Requirements.

SAS

CONTEXT [SCSI]

Acronym for Serial Attached SCSI.

SAS Expander

CONTEXT [SCSI]

Short form of Serial Attached SCSI Expander

SATA

Acronym for Serial Advanced Technology Attachment.

saturated disk

A disk whose instantaneous I/O load is as great as or greater than its capability to satisfy the requests comprising the load. Mathematically, a saturated disk's I/O queue eventually becomes indefinitely long. In practice, however, user reaction or other system factors generally reduce the rate of new request arrival for a saturated disk.

scale (verb)

In computer systems, to grow or support growth in such a way that all capabilities of the system remain in constant ratio to each other. For example, a storage subsystem whose data transfer capacity increases by the addition of buses as its storage capacity increases by the addition of disks is said to scale.

schema

A collection of information models or data models.

script

1. A parameterized list of primitive I/O bus operations intended to be executed in sequence. Often used with respect to ports, most of which are able to execute scripts of I/O commands autonomously (without policy processor assistance).
2. A sequence of instructions intended to be parsed and carried out by another program. Perl, VBScript, JavaScript and Tcl are all scripting languages.

SCSI

CONTEXT [SCSI]

Acronym for Small Computer System Interface.

SCSI adapter

CONTEXT [SCSI]

An adapter that connects an intelligent device to a SCSI bus. cf. HBA, host bus adapter

SCSI address

CONTEXT [SCSI]

The full address used by a computer to communicate with a SCSI device, including an adapter number (required with computers configured with multiple SCSI adapters), and the target ID of the device. SCSI addresses do not include logical unit number, because those are not used for communication.

SCSI Architecture Model

CONTEXT [SCSI]

An ANSI standard that defines the generic requirements and overall framework in which other SCSI standards are defined. New generations of this standard are identified by a numeric suffix; for example the second generation standard is SAM2.

SCSI bus

CONTEXT [SCSI]

Any parallel (multi-signal) I/O bus that implements some version of the ANSI SCSI standard. A wide SCSI bus may connect up to16 initiators and targets. A narrow SCSI bus may connect up to eight initiators and targets. cf. initiator, target

SCSI Device

CONTEXT [SCSI]

This is the SAM-2 term for an entity that contains other SCSI entities. For example, a SCSI Initiator Device contains one or more SCSI Initiator Ports and zero or more application clients.

SCSI Enclosure Services

CONTEXT [SCSI]

An ANSI X3T10 standard for management of environmental factors such as temperature, power, voltage, etc. Abbreviated SES.

SCSI Initiator Port

CONTEXT [SCSI]

The initiator endpoint of an I_T nexus.

SCSI Parallel Interface

CONTEXT [SCSI]

The family of SCSI standards that define the characteristics of the parallel version of the SCSI interface. Abbreviated SPI. Several versions of SPI, known as SPI, SPI2, SPI3, etc., have been developed. Each version provides for greater performance and functionality than preceding ones.

SCSI Port

CONTEXT [SCSI]

This is the SAM-2 term for an entity in a SCSI Device that provides the SCSI functionality to interface with a service delivery subsystem or transport.

SCSI Target Port

CONTEXT [SCSI]

The target endpoint of an I_T nexus.

SCSI Trade Association

A trade association incorporated 1996 to promote all forms of SCSI technology in the market. Abbreviated STA. cf. http://www.scsita.org/

SDH

CONTEXT [Network]

Acronym for Synchronous Digital Hierarchy.

sector

CONTEXT [Storage Device]

The unit in which data is physically stored and protected against errors on a fixed block architecture disk. A sector typically consists of a synchronization pattern, a header field containing the block’s address, data, a checksum or error correcting code, and a trailer. Adjacent sectors are often separated by information used to assist in track centering. Most often, each sector holds a block of data. cf. disk block

secure hash

CONTEXT [Security]

An algorithm that generates a digest from its input (e.g., a message). The digest has the properties that different inputs are extraordinarily unlikely to have the same fingerprint, small changes in its input lead to large changes in its output, and it is computationally intractable to generate an input that has the same fingerprint as a given input.

Secure Hash Algorithm 1

CONTEXT [Security]

A message digest algorithm that produces a 160 bit digest. SHA-1 is defined in RFC3174. Acronym SHA-1.

Secure Remote Password

CONTEXT [Security]

An authentication and key exchange system. Standardized by the Internet Engineering Task Force and described in RFC 2945. Acronym SRP.

Secure Sockets Layer

CONTEXT [Security]

A suite of cryptographic algorithms, protocols and procedures used to provide security for communications used to access the world wide web. Abbreviated SSL. The characters "https:" at the front of a URL cause SSL to be used to enhance communications security. More recent versions of SSL are known as TLS (Transport Level Security) and are standardized by the Internet Engineering Task Force (IETF)

security association

CONTEXT [Security]

A simplex "connection" that affords security services to the traffic carried by it. To secure typical, bi-directional communication between two hosts, or between two security gateways, two Security Associations (one in each direction) are required. In IPsec, a security association is uniquely identified by a triple consisting of a Security Parameters Index (SPI), an IP Destination Address, and a security protocol identifier (Authentication Header or Encapsulating Security Payload). Acronym SA.

Security Assurance Requirements

CONTEXT [Security]

• A set of assurance components (classes and families) that represent a standard way of expressing the assurance requirements for TOEs. These requirements are drawn from ISO 15408-3:1999, whenever possible. Acronym SAR.
• The protective measures and controls that are prescribed to meet the security requirements specified for a system. Those safeguards may include but are not necessarily limited to: hardware and software security features, operating procedures, accountability procedures, access and distribution controls, management constraints, personnel security, and physical structures, areas, and devices. Also called safeguards.

Security Functional Requirements

CONTEXT [Security]

A set of security functional components (classes and families) that represent a standard way of expressing the functional requirements for TOEs. These requirements are drawn from ISO 15408-2:1999, whenever possible. Acronym SFR.

Security Parameters Index

CONTEXT [Security]

A 32-bit number used to uniquely identify a security association (SA). In IP Security, SPI values must be synchronized between endpoints for the security functions to work properly. SPI values 1 through 255 have been reserved for use with standard implementations. Acronym SPI.

Security Target

CONTEXT [Security]

A set of security functional and assurance requirements and specifications to be used as the basis for evaluation of an identified product or system. It is most commonly associated with ISO 15408. Acronym ST.

SEQ_ID 

Sequence Identifier

CONTEXT [Fibre Channel]

A number transmitted with each data frame in a sequence that identifies the frame as part of the sequence.

sequence

CONTEXT [Fibre Channel]

A set of Fibre Channel data frames with a common Sequence_ID (SEQ_ID), corresponding to one message element, block, or Information Unit. Sequences are transmitted from the sequence initiator to the sequence recipient.

sequence initiative

CONTEXT [Fibre Channel]

A Fibre Channel signaling feature that designates which end of an exchange has authority to send the next sequence.

Sequence Initiator

CONTEXT [Fibre Channel]

An N_Port that initiates a sequence and transmits data frames to a destination Nx_Port.

Sequence Recipient 

CONTEXT [Fibre Channel]

An N_Port or NL_Port which receives Data frames from a Sequence Initiator and, if applicable, transmits responses (Link Control frames) to the Sequence Initiator.

Sequence Status Block

CONTEXT [Fibre Channel]

A data structure which tracks the state of a sequence. Both Sequence Initiators and Sequence Recipients have Sequence Status Blocks for each active sequence.

sequential I/O

sequential I/O load

sequential reads

sequential writes

An I/O load consisting of consecutively issued read or write requests to adjacently located data. Sequential I/O is characteristic of data transfer intensive applications. cf. random I/O

SERDES

Acronym for Serializer Deserializer.

serial (transmission)

CONTEXT [Fibre Channel]

The transmission of data bits one at a time over a single link.

serial adapter

An adapter that connects an intelligent device to an RS232 or RS425 serial communications link. Serial adapters are sometimes used by storage subsystems, filers, and other intelligent devices to connect to serial consoles for management purposes. cf. adapter, host adapter

Serial Advanced Technology Attachment

Serial ATA (SATA) is the evolution of the ATA interface from a parallel bus to serial connection architecture. Acronym SATA.

Serial Attached SCSI

CONTEXT [SCSI]

A SCSI interface standard that provides for attaching HBAs and RAID controllers to both SAS and SATA disk and tape drives, as well as other SAS devices. INCITS Technical Committee T10 is responsible for the national (ANSI) and international (ISO) standards for SAS, cf. www.t10.org .

Serial Attached SCSI Expander

CONTEXT [SCSI]

A switching device that allows multiple SAS devices to be connected to each other.

serial console

A real or emulated communication terminal used by humans to manage an intelligent device. Serial consoles connect to the devices’ serial adapters.

serial SCSI

CONTEXT [SCSI]

Any implementation of SCSI that uses serial data transmission (as opposed to multi-conductor parallel buses). Optical and electrical Fibre Channel and IEEE 1394 are examples of serial SCSI implementations.

serializer deserializer

A mechanism for converting data from parallel to serial form and from serial to parallel form.

server

1. An intelligent device, usually a computer, that provides services to other intelligent devices, usually other computers or appliances. cf. client
2. An asymmetric relationship with a second party (a client) in which the client initiates requests and the server responds to those requests.

server based virtualization

Virtualization implemented in a host computer rather than in a storage subsystem or storage appliance. Virtualization can be implemented either in host computers, in storage subsystems or storage appliances, or in a specific virtualization appliances in the storage interconnect fabric.

serverless backup

CONTEXT [Data Recovery]

A backup methodology that utilizes a device other than the server to copy data without using the LAN. The copy may be performed by a network-attached controller (e.g., utilizing SCSI Extended Copy), by an appliance within the SAN, or by a Backup Server.

Server Message Block (protocol)

CONTEXT [Network]

A network file system access protocol designed primarily used by Windows clients to communicate file access requests to Windows servers. Abbreviated SMB. Current versions of the SMB protocol are usually referred to as CIFS, the Common Internet File System.

service level agreement

An agreement between a service provider, such as an IT department, an internet services provider, or an intelligent device acting as a server, and a service consumer. A service level agreement defines parameters for measuring the service, and states quantitative values for those parameters. Abbreviated SLA.

Service Level Objective - SLO

CONTEXT [Information Lifecycle Management]

Partitions an SLA into individual metrics and operational information to enforce and/or monitor the SLA. "Service Level Objectives" may be defined as part of an SLA, an SLS, or in a separate document. It is a set of parameters and their values. The actions of enforcing and reporting monitored compliance can be implemented as one or more policies. (See also "Service Level Agreement".).

Service Location Protocol

An IETF standards track protocol that provides a framework to allow networking applications to dynamically discover the existence, location, and configuration of networked services in enterprise networks. Acronym SLP.

SES

CONTEXT [SCSI] [Standards]

1. Acronym for SCSI Enclosure Services
2. Acronym for Solution Exchange Standard.

SF_ID

CONTEXT [Fibre Channel]

Acronym for source Fabric_Identifier.

SFR

CONTEXT [Security]

Acronym for Security Functional Requirements.

SHA-1

CONTEXT [Security]

Acronym for Secure Hash Algorithm 1.

share

CONTEXT [File System

A resource such as data or a printer device made available for use by users on other computer systems. For example, a printer or a collection of files stored in a single directory tree on a file server may be made available as a share. CIFS clients, which include most networked personal computers, typically map a share to a drive letter.

shielded enclosure

CONTEXT [Security]

A room or container designed to attenuate electromagnetic radiation.

shelf

CONTEXT [Storage System]

A modular enclosure for storage devices (disks and tapes). Storage shelves usually contain power supplies and cooling devices, and have pre-wired backplanes that carry power and I/O bus signals to the devices mounted in them. cf. canister

SIA

1. Acronym for Semiconductor Industries Association.
2. Acronym for SCSI Industry Association.

Simple Network Management Protocol

CONTEXT [Network] [Standards

An IETF protocol for monitoring and managing systems and devices in a network. The data being monitored and managed is defined by a MIB. The functions supported by the protocol are the request and retrieval of data, the setting or writing of data, and traps that signal the occurrence of events.

single (component) configuration

A configuration in which the referenced component is not redundant. cf. redundant (component)

single ended (signaling) 

CONTEXT [SCSI

An electrical signaling technique in which all control and data signals are represented by a voltage difference from a common ground. cf. differential

single mode (fiber optic cable)

CONTEXT [Fibre Channel] [Network]

A fiber optic cabling specification that provides for up to 10 kilometer distance between devices.

single mode fibre

CONTEXT [Fibre Channel]

Optical fiber that is designed for the transmission of a single ray or mode of light as a carrier. Single mode fibre transmission is typically used for long-distance signal transmission.

single point of failure

One component or path in a system, the failure of which would make the system inoperable. Abbreviated SPOF.

SIS

CONTEXT [Management] [Standards

Acronym for Service Incident Standard.

SLA

Acronym for Service Level Agreement.

SLP

Acronym for Service Location Protocol.

Small Computer System Interface (SCSI)

CONTEXT [SCSI

A collection of ANSI standards and proposed standards which define I/O buses primarily intended for connecting storage subsystems or devices to hosts through host bus adapters. Originally intended primarily for use with small (desktop and desk-side workstation) computers, SCSI has been extended to serve most computing needs, and is arguably the most widely implemented I/O bus in use today.

small read request

small write request

small I/O request

An I/O, read, or write request that specifies the transfer of a relatively small amount of data. ‘Small’ usually depends on the context, but most often refers to 8 KBytes or fewer. cf. large I/O request

SMB

CONTEXT [File System] [Network]

Acronym for Server Message Block.

SMI

The Storage Networking Industry Association's (SNIA) Storage Management Initiative (SMI) develops and standardizes interoperable storage management technologies, including providing conformance testing for products.

SMI-S

CONTEXT [SNIA][Standards]

Acronym for Storage Management Initiative - Specification.

SMPTE

CONTEXT [Standards

Acronym for Society of Motion Picture and Television Engineers.

snapshot

CONTEXT [Data Recovery] [Storage System]

A fully usable copy of a defined collection of data that contains an image of the data as it appeared at the point in time at which the copy was initiated. A snapshot may be either a duplicate or a replicate of the data it represents.

SNIA

CONTEXT [Network] [Standards] [Storage System]

Acronym for Storage Networking Industry Association.

sniffer

CONTEXT [Security]

A software tool for auditing and identifying network traffic packets.

SNMP

CONTEXT [Network] [Management

Acronym for Simple Network Management Protocol.

SNS

CONTEXT [Network]

Acronym for Simple Name Server.

Society of Motion Picture and Television Engineers

CONTEXT [Standards

An indistry association whose goal is to standardize television and motion picture industry information interchange protocols.

soft link

CONTEXT [File System]

Synonym for symbolic link.

soft zone

CONTEXT [Fibre Channel]

A zone consisting of zone members that are permitted to communicate with each other via the fabric.

Soft zones are typically implemented through a combination of name server and Fibre Channel protocol -- when a port contacts the name server, the name server returns information only about Fibre Channel ports in the same zone(s) as the requesting port. This prevents ports outside the zone(s) from being discovered and hence the Fibre Channel protocol will not attempt to communicate with such ports. In contrast to hard zones, soft zones are not enforced by hardware; e.g., a frame that is erroneously addressed to a port that should not receive it will nonetheless be delivered. Well known addresses {link} are implicitly included in every zone. cf. zone, hard zone

SOF

CONTEXT [Fibre Channel]

Acronym for start of frame.

solicited control

CONTEXT [Fibre Channel]

An information category indicated in a Fibre Channel frame header.

solicited data

CONTEXT [Fibre Channel]

An information category indicated in a Fibre Channel frame header.

solid state disk

CONTEXT [Storage Device

A disk whose storage capability is provided by solid-state random access memory rather than magnetic or optical media. A solid state disk generally offers very high access performance compared to that of rotating magnetic disks, because it eliminates mechanical seek and rotation time. It may also offer very high data transfer capacity. Cost per byte of storage, however, is typically quite high, and volumetric density is lower. A solid state disk include some mechanism such as battery backup or magnetic backing store that allows its operating environment to treat it as non-volatile storage. cf. RAMdisk

Solution Exchange Standard

CONTEXT [Management

A DMTF standard that defines the exchange of support or help desk information.

Service Incident Standard

CONTEXT [Management

A DMTF standard that defines how a support or help desk incident is processed.

SONET

CONTEXT [Network]

Acronym for Synchronous Optical Network.

Source Identifier

CONTEXT [Fibre Channel]

A number in a Fibre Channel frame that identifies the source of the frame. Abbreviated S_ID. cf. D_ID

source N_Port

CONTEXT [Fibre Channel]

The NX_Port from which a frame is transmitted.

spare (disk, extent)

CONTEXT [Storage System]

An object reserved for the purpose of substitution for a like object in case of that object's failure.

special character 

CONTEXT [Fibre Channel]

Any transmission character that is valid in the transmission code but does not correspond to a valid data byte. Special characters are used to denote special functions.

special code 

CONTEXT [Fibre Channel]

A code which, when encoded using the rules specified by the transmission code, results in a special character. Special codes are typically associated with control signals related to protocol management (e.g., K28.5).

SPI

Acronym for SCSI Parallel Interface.

CONTEXT [Security]

Acronym for Security Parameters Index.

spiral data transfer rate

Synonym for full volume transfer rate.

split I/O request

1. An I/O request to a virtual disk which requires two or more I/O operations to satisfy, because the virtual data addresses in the request map to more than one extent on one or more disks
2. An application I/O request that is divided into two or more sub-requests by a file system or other operating system component because the amount of data requested is too large for the operating environment to handle as a unit.

split mirror

split mirror copy

split mirror point in time copy

CONTEXT [Storage System]

Any of a class of point in time copy implementations or the resulting copies in which the storage for the copy is synchronized to the source of the copy and then split. A split mirror copy occupies as much storage as the source of the copy.

CONTEXT [Data Recovery]

A method for generating a frozen image of a set of data. A split mirror frozen image is a set of storage devices containing a complete copy of data as of the moment of frozen image creation. When a split mirror frozen image has served its purpose, the contents of the storage devices it occupies must be resynchronized with the original data from which it was split.

SPOF

Acronym for Single Point Of Failure.

spoofing

CONTEXT [Security]

Unauthorized use of legitimate identification and authentication data to mimic a subject different from the attacker. Impersonating, masquerading, piggybacking and mimicking are forms of spoofing.

SR

CONTEXT [Fibre Channel]

Acronym for Sequence Recipient.

SRM

CONTEXT [Management

Acronym for storage resource management.

SRP

CONTEXT [Security]

Acronym for Secure Remote Password.

SSID

CONTEXT [Security]

Acronym for iSCSI Session Identifier.

SSL

CONTEXT [Security]

Acronym for Secure Sockets Layer.

STA

Acronym for SCSI Trade Association .

ST

CONTEXT [Security]

Acronym for Security Target.

stand alone drive

CONTEXT [Data Recovery]

A removable media drive that is not associated with a media stacker or robot.

standard interconnect

CONTEXT [Standards]

An I/O or network interconnect whose specifications are readily available to the public, and which can therefore easily be implemented in a vendor’s products without license or royalty payments. Also called open interconnect.

star

A physical network configuration in which every node is connected directly to, and only to, a central point. All communications pass through the central point, which may be a hub or a switch.

start of frame

CONTEXT [Fibre Channel]

A group of ordered sets that delineates the beginning of a frame.

storage area network

CONTEXT [Fibre Channel] [Network] [Storage System]

1. A network whose primary purpose is the transfer of data between computer systems and storage elements and among storage elements. Abbreviated SAN. A SAN consists of a communication infrastructure, which provides physical connections, and a management layer, which organizes the connections, storage elements, and computer systems so that data transfer is secure and robust. The term SAN is usually (but not necessarily) identified with block I/O services rather than file access services.  
2. A storage system consisting of storage elements, storage devices, computer systems, and/or appliances, plus all control software, communicating over a network.

Note: The SNIA definition specifically does not identify the term SAN with Fibre Channel technology. When the term SAN is used in connection with Fibre Channel technology, use of a qualified phrase such as "Fibre Channel SAN" is encouraged. According to this definition an Ethernet-based network whose primary purpose is to provide access to storage elements would be considered a SAN. SANs are sometimes also used for system interconnection in clusters.

storage array

CONTEXT [Storage System]

A collection of disks or tapes from one or more commonly accessible storage subsystems, combined with a body of control software.

storage controller

CONTEXT [Storage System]

An intelligent controller to which storage devices are attached.

storage device

CONTEXT [Storage Device]

A collective term for disks, tapes, disk arrays, tape arrays, and any other mechanisms capable of non-volatile data storage. This definition is specifically intended to exclude aggregating storage elements such as RAID array subsystems, robotic tape libraries, filers, and file servers.

storage device virtualization

Virtualization of storage devices such as disk, tape drive, RAID shelves, etc.

storage domain

CONTEXT [Storage System]

A collection of storage resources and supporting software and interfaces that are managed as a unit.

storage element

Any device designed and built primarily for the purpose of persistent data storage and delivery. This definition is specifically intended to encompass disk drives, tape drives, RAID array subsystems, robotic tape libraries, filers, file servers, and any other types of storage devices.

storage extent

A contiguous array of bytes-real or virtual-as exposed by a storage container. A storage extent instance may represent either removable or nonremoveable media. cf. extent

storage for grids

Any storage system that meets the storage needs of Grid Computing. The storage systems may or may not have any internal grid-like architecture.

Storage Interoperability

The ability of storage devices, products, or systems to work together in a correct, predictable and interchangeable fashion.

Storage Management Initiative - Specification

CONTEXT [SNIA][Standards]

A standard storage management interface developed by SNIA. Acronym SMI-S.

storage networking

The practice of creating, installing, administering, or using networks whose primary purpose is the transfer of data between computer systems and storage elements and among storage elements.

Storage Networking Industry Association

CONTEXT [Network] [Standards] [Storage System]

An association of producers and consumers of storage networking products whose goal is to further storage networking technology and applications.

storage resource management

CONTEXT [Management]

Management of physcial and logical storage resources, including storage elements, storage devices, appliances, virtual devices, disk volume and file resources.

storage security

CONTEXT [Security]

Technical controls that protect storage resources and data from unauthorized users and may include integrity, confidentiality and availability of the resources and data.

storage subsystem

CONTEXT [Storage System]

An integrated collection of (a.) storage controllers and/or host bus adapters, (b.) storage devices such as disks, CDROMs, tapes, media loaders and robots, and (c.) any required control software, that provides storage services to one or more computers.

storage subsystem virtualization

The implementation of virtualization in a storage subsystem.

storage virtualization

1. The act of abstracting, hiding, or isolating the internal function of a storage (sub) system or service from applications, compute servers or general network resources for the purpose of enabling application and network independent management of storage or data.
2. The application of virtualization to storage services or devices for the purpose of aggregating, hiding complexity or adding new capabilities to lower level storage resources.
   Storage can be virtualized simultaneously in multiple layers of a system, for instance to create HSM like systems.

store and forward (switching)

CONTEXT [Fibre Channel] [Network]

A switching technique that requires buffering an entire frame before it is routed.

stream

CONTEXT [File System] [Network]

1. Continuous media content served over a specialized protocol in real-time.
2. A subfile in the CIFS protocol. NFSv4 provides equivalent functionality using Named Attributes.

streamed sequence

CONTEXT [Fibre Channel]

A new sequence initiated by a Sequence Initiator in any class of service for an exchange while it already has sequences open for that exchange.

strip

CONTEXT [Storage System]

A number of consecutively addressed blocks in a single extent. A disk array’s uses strips to map virtual disk block addresses to member disk block addresses. Also known as stripe element.

strip size

CONTEXT [Storage System]

Synonym for stripe depth .

stripe

CONTEXT [Storage System]

The set of strips at corresponding locations of each member extent of a disk array which uses striped data mapping. The strips in a stripe are associated with each other in a way (e.g., relative extent block addresses) that allows membership in the stripe to be quickly and uniquely determined by a computational algorithm. Parity RAID uses uses stripes to map virtual disk block addresses to member extent block addresses.

stripe depth

CONTEXT [Storage System]

The number of blocks in a strip in a disk array which uses striped data mapping. Also, the number of consecutively addressed virtual disk blocks mapped to consecutively addressed blocks on a single member extent of a disk array.

stripe element

CONTEXT [Storage System]

Synonym for strip.

stripe size

CONTEXT [Storage System]

The number of blocks in a stripe. A striped array’s stripe size is the stripe depth multiplied by the number of member extents. A parity RAID array’s stripe size is the stripe depth multiplied by one less than the number of member extents.

striped array

striped disk array

CONTEXT [Storage System]

A disk array with striped data mapping but no redundancy for failure protection. Striped arrays are usually used to improve I/O performance on data that is of low value or easily replaced.

stripeset

CONTEXT [Storage System]

Synonym for striped array.

striping

CONTEXT [Storage System]

1. Short for data striping; also known as RAID Level 0 or RAID 0. A mapping technique in which fixed-size consecutive ranges of virtual disk data addresses are mapped to successive array members in a cyclic pattern
2. A network technique for aggregating the bandwidth of several links between the same pair of nodes. A single data stream can be spread across the links for higher aggregate bandwidth. Sometimes called port aggregation.

Structure of Management Information

CONTEXT [Fibre Channel] [Management] [Network]

A notation for setting or retrieving management variables over SNMP.

SSL

CONTEXT [Security]

Acronym for Secure Sockets Layer

subdirectory

CONTEXT [File System

A directory in a hierarchical directory tree whose parent is a directory.

subject

CONTEXT [Security]

In the context of access control or authorization, an entity whose access or usage is controlled.

substitution

The assumption of a component's function in a system by a functionally equivalent component.

swap

swapping

The installation of a replacement unit in place of a defective unit in a system. Units are any parts of a system which may either field replaceable (FRUs) by a vendor service representative or consumer replaceable (CRUs).

A physical swap operation may be cold, warm, or hot, depending on the state in which the disk subsystem must be in order to perform it. A functional swap operation may be an auto swap or it may require human intervention.

switch

CONTEXT [Fibre Channel] [Network]

A network infrastructure component to which multiple nodes attach. Unlike hubs, switches typically have internal bandwidth that is a multiple of link bandwidth, and the ability to rapidly switch node connections from one to another. A typical switch can accommodate several simultaneous full link bandwidth transmissions between different pairs of nodes. cf. hub

switch-back

Synonym for failback.

Switch_Name

CONTEXT [Fibre Channel]

A Name_Identifier that is associated with a Fibre Channel switch or bridge name.

switch-over

Synonym for failover.

switched over (system)

Synonym for failed over.

symbolic link

CONTEXT [File System]

A special type of file that can be used to redirect a file or directory path transparently to another file or directory that may be on another system. Also known as symlink or soft link. Symbolic links differ from hard links in that deletion of the underlying file causes them to be "broken", and subsequent attempts to traverse them fail.

Symlink

CONTEXT [File System]

Shorthand for a symbolic link.

symmetric cryptosystem

CONTEXT [Security]

A cryptographic algorithm in which the same key is used to encrypt and decrypt a single message or block of stored information. Keys used in a symmetric cryptosystem must be kept secret, yet are required on both ends of a protocol exchange. They are commonly used on a per-session basis by layered protocols such as TLS and SSL.

symmetric virtualization

Synonym for in-band virtualization. In-band virtualization is the preferred term

synchronize

CONTEXT [Storage System]

In the context of data replication, to establish an identical copy of the user data on the primary volume onto the secondary volume.

Synchronous Digital Hierarchy

CONTEXT [Network]

An ISO standard with 155, 622, 2048, 9953 Mbps serial data rates in steps of 4. A common worldwide telecommunications methodology. SDH uses a light scrambling of data to remove only the lowest frequency elements with the goal of achieving maximum digital bandwidth use.

synchronous replication

CONTEXT [Storage System]

A replication technique in which data must be committed to stable storage at both the primary site and the secondary site before the write is acknowledged to the host.

synchronization

CONTEXT [Fibre Channel]

1. A receiver's identification of a transmission word boundary
2. The act of aligning or making two entities be equivalent at a specified point in time.

synchronous operations

Operations which have a fixed time relationship to each other. Most commonly used to denote I/O operations which occur in time sequence, i.e., a successor operation does not occur until its predecessor is complete.

Synchronous Optical Network

CONTEXT [Network]

A standard for optical network elements. Abbreviated SONET. SONET provides modular building blocks, fixed overheads, integrated operations channels, and flexible payload mappings. Basic SONET provides a bandwidth of 51.840 megabits/second. This is known as OC-1. Higher bandwidths that are n times the basic rate are available (known as OC-n). OC-3, OC-12, OC-48, and OC-192 are currently in common use.

system board

A printed circuit module containing mounting devices for processor(s), memory, and adapter cards, and implementing basic computer functions such as memory access, processor and I/O bus clocking, and human interface device attachment.

system disk

The disk on which a computer system's operating software is stored. The system disk is usually the disk from which the operating system is bootstrapped (initially loaded into memory). The system disk frequently contains the computer system's swap and/or page files as well. It may also contain libraries of common software shared among several applications

system under test

An entity being tested to verify functional behavior or determine performance characteristics. Distinguished from test system.

Key Programs

• Data Management Forum
• Green Storage Initiative
• Storage Management Initiative (SMI)
• XAM Initiative