Glossary

This glossary defines the special terms, abbreviations, and acronyms used in this publication and other related publications.

If you do not find the term you are looking for, see the IBM® Glossary of Computing Terms located at the following website: http://www.ibm.com/ibm/terminology.

This glossary defines the special terms, abbreviations, and acronyms used in this publication and other related publications.

The following cross-references are used in this glossary:

See refers you from a term to a preferred synonym, or from an acronym or abbreviation to the defined full form.
See also refers you to a related or contrasting term.

To view glossaries for other IBM products, go to www.ibm.com/software/globalization/terminology (opens in new window).

3U

Three rack-unit

3592 Tape Drives

Refers collectively to:

TS1150 Tape Drives
TS1140 Tape Drives
TS1130 Tape Drives
TS1120 Tape Drives
3592 J1A

A

ac

Alternating current.

ACF

Automatic cartridge facility.

ACS

Automatic class section.

advisory lock

A type of lock that a process holds on a region of a file that signals any other process to not use or lock the region or an overlapping region. Other processes are not forced to comply.

AES

Advanced encryption standard.

AIX®

Advanced interactive executive.

IBM's implementation of the UNIX operating system. The RS/6000® system, among others, runs the AIX operating system.

alter

To change.

ALMS

Advanced library management system.

amp

Ampere.

amsl

Above mean sea level.

AOTM

Autonomic Ownership Takeover Manager.

array

An ordered collection, or group, of physical devices (for example, drives), that provide storage for virtual volumes. An array is a group of drives that are designated to be managed with a Redundant Array of Independent Disks (RAID). See also Redundant Array of Independent Disks.

ASCII

American National Standard Code for Information Interchange

A 7-bit coded character set (8 bits, including parity check) that consists of control characters and graphic characters.

ASMI

Advanced system management interface.

assignment

The naming of a specific device to perform a function.

asynchronous

Pertaining to two or more processes that do not depend upon the occurrence of specific events such as common timing signals.

asynchronous replication

A type of replication in which control is given back to the application as soon as the write operation is made to the source volume. Some time later, the write operation is made to the target volume. See also synchronous replication.

attention (notice)

A word for calling attention to the possibility of danger to a program, device, or system, or to data. Contrast with caution and danger.

ATTN

Attention.

audit log

An unalterable record of all commands or user interactions that are issued to the system.

audit logging

The process of keeping a log of all activities of interest to security personnel. These activities are those that can negatively affect operations if completed incorrectly or maliciously. They include such events as: login attempts, configuration changes, status changes, and code updates.

authentication

The process of recognizing a user through a valid combination of user id and password.

local authentication: Each machine maintains an internal database of user IDs, with corresponding passwords and roles.
Storage Authentication Service policy authentication: A Role-Based Access Control method of authentication that uses LDAP to create a central repository for storage and management of user IDs, passwords, and roles.

authenticated user

A user who has logged in to the system with a valid account (user ID and password).

authorization

The process of authorizing an authenticated user to access a specific resource.

B

back up: To make additional copies of documents or software for safekeeping.
backup object: See OAM.
BCR: Buffer channel remainder register.
bezel: Decorative cover or safety cover.
binding: A term used to refer to the process of persistently saving a type or attribute property of a volume. Before the binding of the property, any derived or assigned properties can be utilized, but they are not permanent until the binding event occurs. When the binding succeeds, the type and or attributes are said to be "bound" to the volume.
block storage: A unit of data storage on a device.
buffer: A routine or storage used to compensate for a difference in rate of data flow or time of occurrence of events, when transferring data from one device to another.
bus: A facility for transferring data between several devices that are located between two end points, only one device being able to transmit at a given moment.
BVIR: Bulk volume information retrieval.

C

°C

Degrees Celsius.

cache

Storage used to improve access times to instructions, data, or both. For example, data that resides in cache memory is normally a copy of data that resides elsewhere in slower, less expensive storage, such as on a disk or on another network node.

cache eviction

A process by which data associated with a file is removed from the cache system. The data is removed either by using a Least Recently Used (LRU) algorithm when configured General Parallel File System (GPFS™) hard or soft quota limits are exceeded or by issuing a command. When referenced again in the cache system, the data that is associated with the file is retrieved from the home system.

caching I/O group

The I/O group in the system that performs the cache function for a volume.

call home

A communication link established between a product and a service provider. The product can use this link to place a call to IBM or to another service provider when it requires service. With access to the machine, service personnel can perform service tasks, such as viewing error and problem logs or initiating trace and dump retrievals.

capacity

The amount of data that can be contained on a storage medium, expressed in bytes of data.

caution (notice)

A word to call attention to possible personal harm to people. Contrast with attention and danger.

CE

IBM service representative (formerly customer engineer).

CEC

Central electronics complex.

CIFS

See Common Internet File System.

CIM

See Common Information Model.

CIM object manager (CIMOM)

The common conceptual framework for data management that receives, validates, and authenticates the CIM requests from the client application. It then directs the requests to the appropriate component or service provider.

CIMOM

See CIM object manager.

CLI

A type of computer interface in which the input command is a string of text characters. See command-line interface.

cluster

A group of computers and other resources that operate together as a single system.

cluster family

A group of clusters all configured with the same family value in vital product data (VPD).

cm

Centimeter.

command

A control signal that initiates an action or the start of a sequence of actions.

command-line interface (CLI)

A computer interface in which the input and output are text based.

Common Information Model (CIM)

An implementation-neutral, object-oriented schema for describing network management or systems management information. The Distributed Management Task Force (DMTF) develops and maintains CIM specifications.

Common Internet File System (CIFS)

A protocol that manages shared, remote file access for applications to files, printers, serial ports, and so on over a TCP/IP network.

Composite Library ID

The library sequence number reported to a host by each attached virtual device

compression

A function that removes repetitive characters, spaces, strings of characters, or binary data from the data being processed and replaces characters with control characters. Compression reduces the amount of storage space that is required for data.

compute node

An independent server that contains one or more microprocessors, memory, storage, and network controllers and runs its own operating system and applications.

concurrent copy

A function of the DFSMSdss component that is used to back up any collection of data at a point in time with minimum down time for the database or application that uses the collection of data.

concurrent

Refers to diagnostic, maintenance, or replacement procedures that can be performed on a system without interrupting customer applications.

construct

A collective term used to refer to the policies that automate storage management through classification of data sets. These include:

Storage Groups;
Management Classes;
Storage Classes;
Data Classes.

controller

Also called control unit, or CU.

copy

The replication of a virtual volume from one site to another across the connecting infrastructure

count key data

An architecture for a direct access storage device (DASD) device or logical device that specifies the access mechanisms for the logical data units on the device through a specific set of supported channel commands. Extensions to the CKD command set form the basis of Extended CKD.
In System z®, a data recording format that uses self-defining record formats in which each record on a volume is represented by up to three fields: a count field identifying the record and specifying its format, an optional key field that can be used to identify the data area contents, and an optional data field that typically contains the user data.

CPU

Central processing unit.

CRC

Cyclic redundancy check: an error detection technique used by the data link layer to determine if all the bits that were sent were also received.

CST

Cartridge storage tape.

CSV

Comma-separated value.

ctrl

Control key.

CU

Control unit. Also called controller.

CUID

A world-unique, 12-byte, 24-hex digit value assigned to a media cartridge that identifies a volume beyond volume serial. This identifier is also referred to as a World Wide Identifier (WWID).

cylinder

A unit of storage on a count-key-data (CKD) device with a fixed number of tracks.

D

DAA

Device allocation assistance.

danger (notice)

A word to call attention to possible lethal harm to people. Contrast with attention and caution.

DASD

Direct access storage device.

data

Any representations such as characters or analog quantities to which meaning is or might be assigned.

data consistency

A characteristic of the data at the target site where dependent write order is maintained to guarantee the recoverability of applications.

data record

The basic unit of S/390® and zSeries storage on an ESS, also known as a count-key-data (CKD) record. See also count key data, fixed-block architecture.
A basic unit of data recording format that is also known as a count-key-data (CKD) record.

dc

Direct current.

DDM

Disk drive module.

A field-replaceable unit (FRU) that consists of a single disk drive and its associated packaging; also see E-DDM and EV-DDM.

DDP

Dynamic Disk Pools.

A form of RAID that can continue to process read and write requests to all of an array's virtual disks in the presence of two concurrent, and up to four disk failures.

Dynamically distributes data, spare capacity, and protection information across a pool of disk drives.

DDR1

Double data rate.

degraded

Decreased quality of output or throughput or increased machine error rate.

destage

To move data from cache to a nonvolatile storage medium.

detent

A catch or lever that holds another part in place.

Device allocation assistance

A function that allows the host to query the TS7740 to determine which clusters should be preferred for a private (specific) mount request.

DFSMS

Data Facility System Managed Storage.

An operating environment that helps automate and centralize the management of storage. The storage administrator can use DFSMS to control data class, storage class, management class, storage group, and automatic class selection routine definitions to manage their storage.

DFSMSdfp

Data Facility System Managed Storage Data Facility Product.

A DFSMS functional component or base element of z/OS®, that provides functions for storage management, data management, program management, device management, and distributed data access.

DFSMShsm

Data Facility System Managed Storage Hierarchical Storage Management.

A functional component of DFSMS that provides facilities for managing storage devices. It is an automated hierarchical storage manager and productivity tool designed to support availability management, space management, and disaster recovery.

DHCP

Dynamic host configuration protocol.

In the Internet suite of protocols, a client/server protocol that is used to centrally locate and distribute configuration information.

disk-only

A cluster that does not attach to a physical tape library; it stores all data in cache.

Distributed Library ID

The unique library sequence number possessed by each cluster in a grid configuration.

DK

Data key

DMA

Direct memory access.

DRAM

Dynamic random-access memory.

Storage in which the cells require repetitive application of control signals to retain stored data.

drive

A data storage device. A drive can be either a magnetic disk drive or a solid-state drive (SSD).

DST

Dedicated service tool.

The part of the service function used to service the system when the operating system is not running.

DVD RAM

Digital video disk random-access memory.

DVD-ROM

Digital video disk read-only memory.

DWDM

Dense wavelength-division multiplexing.

E

EBCDIC: Extended binary-coded decimal interchange code.; A coded character set consisting of 8-bit coded characters.
EBTERM: Terminal emulator for OS/2.
EC: Edge connector, also; Engineering change.
ECC: Error checking and correction, also; Error correction code.
ECCST: Extended capacity cartridge storage tape.
ECKD™: See extended count key data.
E-DDM and EV-DDM: Enhanced disk drive module and enhanced value disk drive module.
EEDK: Externally encrypted data key.
EEH: Extended (or enhanced) error handling.
EEPROM: Electrically erasable programmable read-only memory.
EIA: Electronics Industries Association.
EIA unit: A unit of measure established by the Electronic Industries Association that is equal to 44.45 mm (1.75 in.).
EiB: Exbibyte; IEC Standard is 1024 pebibytes.
EKM: Entry key mask.
EMC: Electromagnetic compatibility.
empty: A word describing a physical or virtual tape entity that contains no data.
enclosure: The metal structure in which various electronic components are mounted.
EPO: Emergency power off.
EPROM: Erasable programmable read-only memory.; A type of memory chip that can retain its contents without electricity. Unlike the programmable read-only memory (PROM), which can be programmed only once, the EPROM can be erased by ultraviolet light and then reprogrammed.
equipment check: An asynchronous indication of a malfunction
EREP: Environmental recording, editing, and printing; The program that formats and prepares reports from the data contained in the error recording data set.
Error log: A data set or file in a product or system where error information is stored for later access
ESCON: Enterprise systems connection; A peripheral interface for an Enterprise Systems Architecture/390 and zSeries computer. The I/O interface uses ESA/390 virtual protocols over a serial interface that configures attached units to a communication fabric.
ESD: Electrostatic discharge; The flow of current that results when objects having a static charge come into close enough proximity to discharge.; An undesirable discharge of static electricity that can damage equipment and degrade electrical circuitry.
ESS: Embedded Security Services or Enterprise Security Services; A Tivoli® component for authentication that provides an abstraction layer between storage devices and an LDAP server.
extended count key data (ECKD): An extension of the count-key-data (CKD) architecture. It includes additional commands that can be used to improve performance.

F

°F: Degrees Fahrenheit
failback: The restoration of an appliance to its initial configuration after detection and repair of a failed network or component.
failover: An automatic operation that switches to a redundant or standby system or node in the event of a software, hardware, or network interruption. See also failback.
fault symptom code (FSC): A hexadecimal code generated by the drive or the control unit microcode in response to a detected subsystem error
FBA: See fixed-block architecture.
FC: See Fibre Channel.
FCIP: See Fibre Channel over IP.
FCP: Fibre channel protocol.; The serial SCSI command protocol used on fibre-channel networks.
FE: IBM service representative (formerly field engineer).
Fibre Channel (FC): A technology for transmitting data between computer devices. It is especially suited for attaching computer servers to shared storage devices and for interconnecting storage controllers and drives. See also zoning.
Fibre Channel extender: A device used to extend a Fibre Channel link over a greater distance than is supported by the standard, usually a number of miles or kilometers. Devices must be deployed in pairs at each end of a link.
Fibre Channel over IP (FCIP): A network storage technology that combines the features of the Fibre Channel Protocol and the Internet Protocol (IP) to connect distributed SANs over large distances.
FFC: Failing function code.
FICON®: Fibre connection channel; A fibre-channel communication protocol designed for IBM mainframe computers and peripherals.
FID: FRU Identifier (may be more than one FRU).
file: A named set of records stored or processed as a unit. Also referred to as a data set.
field-replaceable unit (FRU): An assembly that is replaced in its entirety when any one of its components fails.
file module: A component that provides file systems to network users. A file module must be provided with storage for the file systems.
file system: A collection of files and certain attributes associated with those files.
file system storage: Data storage that is organized into files and directories.
fixed-block architecture (FBA): An architecture for a virtual device that specifies the format of and access mechanisms for the virtual data units on the device. The virtual data unit is a block. All blocks on the device are the same size (fixed size). The system can access them independently. See also data record.
FlashCopy®: Pertaining to a point-in-time copy where a virtual copy of a volume is created. The target volume maintains the contents of the volume at the point in time when the copy was established. Any subsequent write operations to the source volume are not reflected on the target volume.
flush-through mode: See write-through mode.
format: The arrangement or layout of data on a data medium.
frame: The hardware support structure, covers, and all electrical parts mounted therein that are packaged as one entity for shipping.
FRU: See field-replaceable unit.
FSC: Fault symptom code.
ft.: Feet.
FTP: File transfer protocol.
functional microcode: Microcode that is resident in the machine during normal customer operation.

G

g: Gram.
Gb: Gigabits; IEC Standard is 1000 megabytes.
GB: Gigabytes.
Gbps: Gigabits per second.
GHz: Gigahertz.
GiB: Gibibyte; IEC Standard is 1024 mebibytes.
Global Mirror: A method of an asynchronous replication that maintains data consistency across multiple volumes within or across multiple systems. Global Mirror is generally used where distances between the source site and target site cause increased latency beyond what the application can accept.
GMT: Greenwich Mean Time.
gNode: The combination of the distributed nodes hNode and vNode in the TS7700.
grid: A series of clusters connected to one another by means of TCP/IP to form a disaster recovery solution where virtual volume attributes and data are replicated across the clusters to ensure the continuation of production work.
grid network: The TCP/IP infrastructure connecting a grid.
GUI: Graphic user interface.

H

Hardware Management Console (HMC)

A system that controls managed systems, including the management of logical partitions and use of Capacity Upgrade on Demand. Using service applications, the HMC communicates with managed systems to detect and consolidate information, which is then sent to IBM for analysis.

HBA

Host bus adapter.

HCD

Hardware configuration definition.

hertz (Hz)

Unit of frequency. One hertz equals one cycle per second.

hex, HEX

Hexadecimal.

HIPPI

High performance parallel interface.

HMC

See Hardware Management Console.

hNode

A distributed node in the TS7700 that performs all management of a virtual volume residing in disk cache or physical tape after it has been created or altered by the host system through a vNode.

host interface card

An optional part of a node canister that provides the system with additional host and storage connectivity options.

hot token

Term applied to a token when a cluster attempts to merge the token's information with other clusters but is prevented from doing so because the other clusters are not available for the merge operation. (Tokens are internal data structures that are used to track changes to the ownership, data, or properties of a logical volume.)

HSL

High-speed link.

HSM

Hierarchical storage management

An automatic method to manage and distribute data between different storage layers. The storage layers can include high-performance disk units, compressed disk units, and tape library devices. Data movement within HSM is described using the following terms:

Ln: Level 0; A volume that contains data sets directly accessible by the user.
ML1: Migration level 1; A volume that is owned by DFSMShsm that contains data sets migrated from an Ln volume. ML1 migrated data also resides on disk and is in a proprietary format managed by HSM. ML1 migrated data must be recalled to Ln before the data can be accessible to a user. See DFSMShsm.
ML2: Migration level 2; A volume that is owned by DFSMShsm that contains data sets migrated from an Ln or ML1 volume. ML2 migrated data can reside on disk or tape (typically tape) and is in a proprietary format managed by HSM. ML2 migrated data must be recalled to Ln before the data can be accessible to a user. See DFSMShsm.

HTML

Hypertext markup language.

Hz

Hertz (cycles per second)

I

IB: InfiniBand.; A point-to-point high-speed switch fabric interconnect architecture.
ICSF: Integrated cryptographic service facility.
ID: Identification, also; Identifier.
identifier (ID): In programming languages, a lexical unit that names a language object; for example, the names of variables, arrays, records, labels, or procedures. An identifier usually consists of a letter optionally followed by letters, digits, or other characters.; One or more characters used to identify or name a data element and possibly to indicate certain properties of that data element.; A sequence of bits or characters that identifies a program, device, or system to another program, device, or system.
IEC: International Electrochemical Commission.
IML: Initial microprogram load.
in.: Inch.
initial microprogram load (IML): The action of loading a microprogram from external storage to writable control storage
initiator: The component that executes a command. The initiator can be the host system or the tape control unit.
input/output (I/O): Pertaining to a device, process, channel, or communication path involved in data input, data output, or both.
interface: A shared boundary. Examples include a hardware component to link two devices or a portion of storage or registers accessed by two or more computer programs.
interface node: A node that connects a system to an Internet Protocol (IP) network for file-serving capabilities by using service protocols.
interposer: The part used to convert a 68-pin connector to a 50-pin D-shell connector.
intervention required: Manual action is needed.
I/O: See input/output.
IOA: Input/output adapter; A functional unit or a part of an I/O controller that connects devices to an I/O processor.; For devices, the electrical circuits on a logic card that connect one device to another.
IOP: Input/output processor.; A functional unit or the part of an I/O controller that processes programmed instructions and controls one or more input/output devices or adapters.
IP: Internet protocol
IPL: Initial program load.; The process that loads the system programs from the system auxiliary storage, checks the system hardware, and prepares the system for user operations.
ISMF: Interactive storage management facility.; An Interactive System Productivity Facility (ISPF) application that provides an interactive set of space management functions for users and storage administrators.

J

JCL: Job control language.; A command language that is used to identify a job to an operating system and to describe the job's requirements.

K

KB: Kilobyte.
KEK: Key-encrypting key.
kg: Kilogram.
KiB: Kibibyte.
km: kilometer.
kVA: Kilovolt amperes.

L

L0

Level 0. See HSM.

L2

Level 2 cache.

lb.

Pound.

LAN

Local Area Network.

A computer network within a limited area.

LC

A type of operational fiber connector.

LDAP

Lightweight Directory Access Protocol.

A standard protocol for authenticating users and authorizing access to resources, typically used to grant access levels to directories on disk.

LED

Light emitting diode.

LM

Library manager.

LMA

Library manager adapter.

loadable

Having the ability to be loaded.

logical

Refer to virtual.

Virtual partition: A subset of a single server that contains resources (processors, memory, and input/output devices). A logical partition operates as an independent system. If hardware requirements are met, multiple logical partitions can exist within a system.

LPAR

A function that enables the creation of logical partitions. See logical partition.

LTPA

Lightweight Third-Party Authentication, also called Single-Sign-On.

An authentication process that uses a cookie containing an LTPA token to enable a web user to reuse the same login across physical servers.

LW

Long wave laser.

M

m: Meter.
magnetic tape: A tape with a magnetic surface layer on which data can be stored.
management node: A node that is used for configuring, administering, and monitoring a system.
MAP: Maintenance analysis procedure; In hardware maintenance, a step-by-step procedure that assists an IBM service representative to trace a symptom to the cause of the failure.
mask: A pattern of characters that controls the retention or elimination of portions of another pattern of characters.; To use a pattern of characters to control the retention or elimination of portions of another pattern of characters.
MB: Megabytes.
Mbps: Megabits per second.
MDE: Microcode detected error.
MES: Miscellaneous equipment specification.; An equipment installation or upgrade that is performed on site by an IBM Service Representative.
Metro Global Mirror: A cascaded solution where Metro Mirror synchronously copies data to the target site. This Metro Mirror target is the source volume for Global Mirror that asynchronously copies data to a third site. This solution has the potential to provide a disaster recovery with no data loss at Global Mirror distances when the intermediate site does not participate in the disaster that occurs at the production site.
Metro Mirror: A method of synchronous replication that maintains data consistency across multiple volumes within the system. Metro Mirror is generally used when the write latency caused by the distance between the source site and target site is acceptable to application performance.
MHz: Megahertz.
MiB: Mebibyte.
micro: One millionth.
microcode: One or more microinstructions.; A code, representing the instructions of an instruction set, implemented in a part of storage that is not program-addressable.; To design, write, and test one or more microinstructions.; See also microprogram.
microinstruction: A basic or elementary machine instruction.
microprogram: A group of microinstructions that when executed performs a preplanned function.
The term microprogram represents a dynamic arrangement or selection of one or more groups of microinstructions for execution to perform a particular function. The term microcode represents microinstructions used in a product as an alternative to hard-wired circuitry to implement certain functions of a processor or other system component.
MIM: Media information message.
ML1: Migration level 1. See HSM.
ML2: Migration level 2. See HSM.
mm: Millimeter.
MM: Multimode fiber.
modifier: An element that changes the meaning of another element or instruction.
mount: A host command to load a tape cartridge into a tape drive. See physical mount:.; A virtual action in which a virtual volume is assigned to a virtual tape drive. See virtual:.
ms: Millisecond.
MTMS: Machine type/model/serial number.
multipath: Describing a situation in which more than one path has been defined.
MVS™: Multiple virtual storage.

N

N/A: Not applicable.
NAT: Network address translation.; The conversion of a network address that is assigned to a logical unit in one network into an address in an adjacent network.; In a firewall, the conversion of secure Internet Protocol (IP) addresses to external registered addresses. This enables communications with external networks but masks the IP addresses that are used inside the firewall.
nearline: Pertaining to a type of storage in which data is available in a short amount of time, but not instantly.
nearline SAS drive: A drive that combines the high capacity data storage technology of a Serial Advanced Technology Attachment (SATA) drive with the benefits of a serial-attached SCSI (SAS) interface for improved connectivity.
NENR: Non-Erasable Non-Rewritable.; A compliance term that refers to a solution that not only prevents rewrite (Write Once, Read Many, or, WORM), but also prevents deletion (erasing) through retention. LWORM (logical WORM), used with host software retention characteristics, provide a NENR-compliant solution.
NFS: Network file server.; A protocol, developed by Sun Microsystems, Incorporated, that allows a computer to access files over a network as if they were on its local disks.
NIM: Network installation management.
node: A single processing unit within a system. For redundancy, nodes are deployed in pairs to make up a system.
NONCE: Number used once.; A number or value expected to only occur once in a data payload which greatly decreases the probability that a resulting cryptographic hash against the payload or similar payload will produce the same hash outcome more than once.
NTP: Network time protocol.
NVRAM: Non-volatile random-access memory.; Random access memory (storage) that retains its contents after the electrical power to the machine is shut off. A specific part of NVRAM is set aside for use by the system read-only storage for the boot device list.

O

OAM

Object access method.

An access method for storing unstructured (byte-stream) data that has no record orientation, for example: scanned images, medical records and billing statements. In this way, OAM data differs from traditional data set data. Data stored in OAM is managed within a storage hierarchy consisting of disk, optical and tape. The following terms are used to describe OAM:

primary object: An object that in the OAM storage hierarchy (disk, optical, or tape) that can be retrieved through the OAM Retrieve API. Movement of data within the storage hierarchy is managed through SMS policies. Data that resides on disk is stored in DB2® tables (4K, 32K, LOB).
backup object: The first or second backup copy of a primary object in an object backup storage group. Backup copies reside on optical or tape storage.

Separate from its object support, OAM also uses the concepts of system-managed storage, introduced by SMS, to manage, maintain, and verify tape volumes and tape libraries within a tape storage environment.

ODM

Object data manager.

A data manager intended for the storage of system data. The ODM is used for many system management functions. Information used in many commands and SMIT functions is stored and maintained in the ODM as objects with associated characteristics.

offline

Pertaining to the operation of a functional unit that is not attached to a controlling device such as a mainframe or a control unit. Contrast with online.

online

Pertaining to the operation of a functional unit that is attached to a controlling device such as a mainframe or a control unit. Contrast with offline.

overrun

Loss of data because a receiving device is unable to accept data at the rate it is transmitted.

P

parameter: A variable that is given a constant value for a specified application and that may denote the application.
Partially Online: When at least one vNode is offline and at least one is online.
PC: Personal computer.
PCC: Power® control compartment: the rack component that logically controls the application of alternating current power to the units in the rack.
PCI: Peripheral component interconnect: a local bus for personal computers that provides a high-speed data path between the processor and attached devices.
PDF: Portable document format: a standard specified by Adobe Systems, Incorporated, for the electronic distribution of documents. PDF files are compact; can be distributed globally via email, the web, intranets, or CD-ROM; and can be viewed with the Acrobat Reader.
PDU: Power distribution unit.
Physical volume: A physical tape drive.
PiB: Pebibyte.
PLF: Perform library function.
POR: Power-on reset.
pool: A group of physical tape cartridges.
pool pair: Two storage pools that are required to balance workload. Each storage pool is controlled by a separate node.
port: The physical entity within a host, system, or storage system that performs the data communication (transmitting and receiving) over the Fibre Channel.
POST: Power-on self test.
power-on self test (POST): A series of diagnostic tests that are run automatically by a device when the power is turned on.
Premigration: When a virtual volume is read from the cache DDMs and written to a physical volume.
primary object: See OAM.
PTF: Program temporary fix.; A fix that is made available to all customers. A program temporary fix is tested by IBM. It contains a PTF record.
PtP: Peer-to-peer.
PWR: Power.

R

RACF®

Resource access control facility.

rack

A free-standing structure that can hold multiple servers, storage systems, chassis, switches, and other devices.

(RAID) Redundant Array of Independent Disks

A collection of two or more physical disk drives that present to the host an image of one or more logical disk drives. In the event of a physical device failure, the data can be read or regenerated from the other disk drives in the array due to data redundancy. See also array.

RAID 0: A data striping technique, which is commonly called RAID Level 0 or RAID 0 because of its similarity to common, RAID, data-mapping techniques. It includes no data protection, however, so, strictly speaking, the appellation RAID is a misnomer. RAID 0 is also known as data striping.
RAID 1: A form of storage array in which two or more identical copies of data are maintained on separate media.
RAID 10: A combination of RAID 0 and RAID 1 in which two identical copies of striped data exist, but there is no parity.
RAID 5: A form of parity RAID in which the disks operate independently, the data stripe size is no smaller than the exported block size, and parity check data is distributed across the array's disks.
RAID 6: A form of RAID that can continue to process read and write requests to all of an array's virtual disks in the presence of two concurrent disk failures.

RAM

Random access memory.

random access memory (RAM)

A memory system to which data is entered and from which data is retrieved in a non-sequential manner.

RAS

Reliability, availability, and serviceability.

RBAC

Role-Based Access Control.

A term used to describe centralized Authentication and Authorization.

Recall

When a virtual volume is moved from a physical volume to the cache and becomes a virtual volume.

recoverable error

An error condition that allows continued execution of a program.

ref

Reference.

RIO

RISC input/output.

RISC

Reduced instruction set computing: a computer that uses a small, simplified set of frequently used instructions for rapid processing.

RMM

Removal Media Manager component within host tape management software.

RO

Read only.

ROT

Read ownership takeover.

RPMES

Returned Part Miscellaneous Equipment Specification.

RSA

Rivest-Shamir-Adleman key pairs.

RUN

Rewind unload processing.

R/W

Read/write.

S

s: Second (unit of time).
SAA: Scratch allocation assistance.
SC: A type of optical fiber connector.
Scratch allocation assistance (SAA): An extension of the device allocation assistance (DAA) function for scratch mount requests. It filters the list of clusters in a grid to return to the host a smaller list of candidate clusters specifically designated as scratch mount candidates.
scratch: A word describing a physical tape entity -- like a tape cartridge, a physical volume, or a pool -- that is ready for use by any write job.
SCSI: Small computer system interface.
SDAC: Selective device access control.
SDC: Scan dump control.
SDS: Scan dump size.
sec: Second (unit of time).
Selective device access control (SDAC): A function that allows only certain logical control units or subsystem ids within a composite library to have exclusive access to one or more VOLSER ranges of volumes for host-initiated mounts, ejects, and attributes or categories changes.
Server Message Block (SMB): A protocol that manages requests and responses in a client/server environment so that clients on a network can share files, directories, and devices. See also Common Internet File System, Server Message Block 2.0.
Server Message Block 2.0: A higher performing, more scalable version of Server Message Block (SMB). This protocol can send multiple commands in the same packet and uses larger buffer sizes. See also Common Internet File System, Server Message Block.
SFP: Small Form-factor Pluggable module.
SIM: Service information message: a message, generated by a storage subsystem, that is the result of error event location and analysis. A SIM indicates that some service action is required.
SLDC: Streaming lossless data compression.
SM: Single-mode fiber.
small computer system interface (SCSI): An input and output bus that provides a standard interface between computer systems.
SMB: See Server Message Block.
SMI-S: Storage Management Initiative - Specification.
SMIT: System management interface tool.
SMS: System management services.
SMSplex: System-managed storage complex.; A group of storage devices managed collectively by a single operating system. The system automates storage management through classification of data sets and objects.
SNIA: The Storage Networking Industry Association.
SNMP: Simple Network Management Protocol.; SNMP is used to monitor network-attached devices.
SNMP MIB: Simple Network Management Protocol Management Information Block.; A file used by an SNMP monitoring application to relate a message identifier to a corresponding text string
SNMP Monitoring Application: An application running on a network-attached server. It receives SNMP traps from network-attached devices, expands those traps using a MIB file, and can take a variety of actions based on the SNMP traps, including filtering , keeping a history log, and sending emails or text messages to users.
SNMP trap: An SNMP message sent by a network-attached device to an SNMP monitoring application. The trap typically contains information to identify the device that sent it, a message identifier, and parameter data.
solid-state drive (SSD): A data storage device that uses solid-state memory to store persistent data.
space efficient: See thin provisioning.
SPCN: System power control network.; An asynchronous serial communications network. SPCN connects the power system in participating components to the operating system and can report critical changes and power failures in those components to the operating system. SPCN gives the operating system control of electrical power.
SR: IBM service representative.
SRAM: Static random access memory.
SRC: System reference code.; A group of characters that identifies the machine status or a specific error condition. The system reference code can be displayed on the console from the problem log.; The characters that identify the name of the unit that detected the condition and the reference code that describes the condition.
SRN: Service Request Number.
SSA: Serial Storage Architecture.; An American National Standards Institute (ANSI) standard, implemented by IBM, for a high-speed serial interface that provides point-to-point connection for peripherals, such as storage arrays.
SSD: See solid-state drive.
SSL: Secure sockets layer.; A security protocol that provides communication privacy. With SSL, client/server applications can communicate in a way that is designed to prevent eavesdropping, tampering, and message forgery.
SSPC: System Storage® Productivity Center.; This is an appliance consisting of an IBM server with preloaded Tivoli software including Tivoli Productivity Center.
Stacked volume: A physical volume that contains more than one virtual volume.
stolen volume: A volume whose ownership has been transferred from one cluster to another through the Autonomic Ownership Takeover Manager (AOTM). The ownership transfer happens when the original owning cluster is unreachable for a period of time.
storage node: A component of a storage system that provides internal storage or a connection to one or more external storage systems.
storage pod: A subcomponent of a network-attached storage (NAS) system that consists of two or more storage nodes and one or more supported storage systems.
storage pool: A collection of storage that identifies an underlying set of resources. These resources provide the capacity and management requirements for a volume or set of volumes.
storage system: A system that provides persistent storage within a network. A storage system can include facilities for host attachment, user role authentication, a command-line interface (CLI), a graphical user interface (GUI), and storage devices that most often include Redundant Array of Independent Disks (RAID) controllers. It might also include agents for enabling third-party management software to monitor or manage the storage devices.
subsystem: A secondary or subordinate system, usually capable of operating independently of, or asynchronously with, a controlling system.
SUID: System unique identification.
SW: Short wave laser.
sync: Synchronous, synchronize. Occurring with a regular or predictable time relationship.
synchronous replication: A type of replication in which the application write operation is made to both the source volume and target volume before control is given back to the application. See also asynchronous replication.
syslog: A standard for transmitting and storing log messages from many sources to a centralized location to enhance system management.

T

TAC: Technical area code.
tape controller: A device that provides the interface between a system and one or more tape drives. Synonymous with control unit.
TB: Terabytes.
TCDB: Tape catalog database.
TCP/IP: Transmission Control Protocol/Internet Protocol.; With regard to a tape library, the protocol used for the LAN communication path between the mainframe and the Library Manager.
TS7700 Cluster: TS7740, TS7720, TS7720T, TS7760, or TS7760T.
TS7700 Disk Only Cluster: A TS7700 server that stores data in disk cache. Characterized by TS7720 Server model 3957-VEB or TS7760 Server model 3957-VEC. When a physical library is attached to a TS7700 Disk Only Cluster, it becomes a TS7700 Tape Attach Cluster.
TS7700 Tape Attach Cluster: A TS7700 with a tape library. TS7740, TS7720T, or TS7760T.
TS7700 cache: Refers collectively to the disk storage media within the TS7700, disk controllers, and disk expansion drawers.
thin-provisioned volume: A volume that allocates storage when data is written to it.
thin provisioning: The ability to define a storage unit (full system, storage pool, volume) with a logical capacity size that is larger than the physical capacity assigned to that storage unit. See also volume.
TiB: Tebibyte
TKLM: Tivoli Key Lifecycle Manager
token: An internal data structure that is used to track changes to the ownership, data, or properties of a logical volume. See also hot token.
TSM: Tivoli Storage Manager
TSSC: TS3000 System Console
TS7700: A TS7740, TS7720, TS7720T, TS7760, or TS7760T server.
TS7720: A TS7700 server that stores data in disk cache and optionally can attach to a physical library. Characterized by TS7720 Server model 3957-VEB.
TS7720T: A TS7700 server that stores data in disk cache and on physical tape in an attached physical library. Characterized by TS7720 Server model 3957-VEB.
TS7740: A TS7700 server that stores data in disk cache and on physical tape in an attached physical library. Characterized by TS7740 Server model 3957-V07.
TS7760: A TS7700 server that stores data in disk cache. Characterized by TS7760 Server model 3957-VEC.
TS7760T: A TS7700 server that stores data in disk cache and on physical tape in an attached physical library. Characterized by TS7760 Server model 3957-VEC.

U

UART: Universal asynchronous receiver/transmitter.
URC: Unit reference code.; The last 4 characters of the SRC.; A group of numbers that are displayed on the console or control panel that identifies failing parts, system or device states, or system or device status conditions.
USB: Universal serial bus.; A Plug-and-Play (Intel standard) interface between a computer and add-on devices (such as keyboards and printers). USB allows a user to add a new device to a computer without having to add an adapter card or to turn the computer off.
utilities: Utility programs.
utility programs: A computer program used for general support of the processes of a computer; for instance, a diagnostic program.

V

V07: A server subsystem for the TS7700 used with an attached library and is specific to the TS7740.
VEB: A server subsystem for the TS7700 used with the disk-only storage solution, one that does not attach to a physical library, and is specific to the TS7720 .
V ac: Volts alternating current.
virtual: Synonymous with the term logical when referring to data stored on DDMs that emulates data stored on physical tape.
Virtual tape drives: Emulated tape drives that occur when the TS7740 Server emulates the function and operation of 3490 Enhanced Capacity (3490E) tape drives.
Virtual volume: Data storage on DDMs that shows the same characteristics to a host application as a physical tape volume and contains data that is written or read through a virtual tape drive.
vNode: A distributed node in the TS7700 that presents the image of virtual drives to the host system.
VOLSER: Volume serial number.; An identification number in a volume label that is assigned when a volume is prepared for use on the system.
volume: A fixed amount of physical or virtual storage on a data storage medium.
volume access set: The set of I/O groups that allows host access to a volume. This set can optionally include the caching I/O group.
VPD: Vital Product Data.; The information that is contained within a component that requires nonvolatile storage used by functional areas of the component, and information required for manufacturing, RAS, and engineering.
VTS: Virtual Tape Server.

W

WAN: Wide area network.; A network that provides communication services between devices in a geographic area larger than that served by a local area network (LAN) or a metropolitan area network.
WBEM: Web-Based Enterprise Management.
word: A character string that is convenient for some purpose to consider as an entity.
WORM: Write Once, Read Many.; Any storage media that allows data to be written only once per storage unit and never changed for secure archival purposes. It is allowed to add new content that does not change previously written units of storage.
WOT: Write-ownership takeover.
Write-mount count: A 16-bit sister value of WWID (World Wide Identifier) that represents the total number of times an LWORM volume is mounted and modified due to a write operation. This value is seeded to zero for a newly bound LWORM volume prior to the first write from BOT (beginning of tape).
write-through mode: A process in which data is written to a storage device at the same time as the data is cached.
WTI: World trade interplant.
WWID: World Wide Identifier.; A world-unique, 12-byte, 24-hex digit value assigned to a media cartridge that identifies a volume beyond volume serial. This identifier is also referred to as a cartridge unique identifier or (CUID).
WWNN: World wide node name: a unique 64-bit identifier for a host containing a fibre-channel port.

Z

z Global Mirror: A method of an asynchronous replication function that maintains data consistency across multiple volumes that are attached to a z/OS system. Time-based data consistency is maintained through the Data Facility Storage Management Subsystem (DFSMS) system data mover (SDM) component.
zone: A collection of Fibre Channel device ports that are permitted to communicate with each other using the fabric. Types of device ports for zone purposes are node ports (N_ports) or node loop ports (NL_ports). Any two N_ports or NL_ports that are not members of at least one common zone are not permitted to communicate using the fabric. See also zoning.
zoning: In Fibre Channel environments, the grouping of multiple ports to form a virtual, private, storage network. Ports that are members of a zone can communicate with each other, but are isolated from ports in other zones. See also Fibre Channel, zone.