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Glossary of Terms

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Term Definition
10GbE 10 Gigabit Ethernet - a version of Ethernet with a nominal data rate of 10 Gbit/sec, ten times as fast as Gigabit Ethernet.
8P8C 8 Position 8 Contact - modular plugs and jacks whose connectors have eight contact pins. Commonly (though mistakenly) called RJ45.
a Ampere - A unit of measure for electric current (equivalent to the current produced by one volt applied across a resistance of one ohm).
AC Alternating Current - This occurs when charge carriers in a conductor or semiconductor periodically reverse their direction of movement.
Access Control Limits user access to resources on a computer network, most commonly by requiring a user name and password.
ack Acknowledge - A signal sent by a station to a terminating station as an affirmative response that a connection has been made, or that data has been received.
ACP Array Control Processor
ACPI Advanced Configuration and Power Interface - An open industry specification establishing industry-standard interfaces enabling OS-directed configuration, power management, and thermal management of mobile, desktop, and server platforms. Most recent revision is 3.0b.
ACSLS Automatic Cartridge System Library Software - Allows implementation of a strategic, centralized library management solution.
AdvancedMC Advanced Mezzanine Card - printed circuit board (PCB) that follows a specification of the PCI Industrial Computers Manufacturers Group (PICMG), targeted to requirements for the next generation of carrier grade communications equipment. Also called AMC for short.
AFR Average Failure Rate - Normally identified as the average time a component might fell within a specific time (interval). However, it could refer to system down time too.
Note: You might see other meaning too, such as Authentication Failure Report, Automatic Feature Recognition, Annual Failure Rate, and so on.
ALOM Advanced Lights Out Management - ALOM builds on the best aspects of LOMLite2 and RSC to provide enhanced features and Ethernet access for applicable systems (servers/hosts). Also see ILOM
AMC See AdvancedMC
AMD Advanced Micro Devices - A global supplier of intergrated circuits (ICs) for personal and network computing and communications.
ANSI American National Standards Institute - An organization that reviews and approves product standards in the U.S. In the electronics industry, its work enables designers and manufacturers to create and support products that are compatible with other hardware platforms in the industry; for example, PHIGS and GKS. See also ISO.
ARC Adaptive Replacement Cache - A page replacement algorithm that improves memory performance. ZFS uses a variant of ARC as an alternative to the traditional Solaris page cache in virtual memory. See also L2ARC.
ASIC Application-Specific Integrated Circuit - A chip designed for a particular application.
ASR Automatic Server Restart - A feature of the LOM module that reduces downtime from system lock-up (allows an administrator to enable an automatic restart of an applicable server/host).
ATA Advanced Technology Attachment - A disk drive interface standard.
Since the advent of SATA, ATA has retroactively been termed PATA (Parallel ATA).
ATAPI ATA Packet Interface - Alternate terminology for ATA.
ATCA Advanced Telecom Computing Architecture - A series of industry standard specifications for the next generation of carrier grade communications equipment. Called the largest specification effort in the history of PICMG.
ATO Assemble To Order - This option can be ordered when the system is first purchased, for installation at the factory. The option will have no leading "X" (example, 9269A).
Aurora Bracket A type of disk drive mounting bracket. Refer to the Mounting Hardware page for more details.
AWG American Wire Gauge - A standardized wire gauge system used in the USA and other countries, especially for nonferrous, electrically conducting wire.
AXQ Address eXtender Queue - An ASIC which performs the function of a system address controller.
BBU Battery Backup Unit
BIOS Basic Input/Output System - This is the computer (host) software that determines what system can do without accessing applicable programs from disk.
Block or Block Size Also known as stripe unit size, block size is often used to describe the amount of data sent or received by the host per I/O operation.
BMC Baseboard Management Controller - a specialized microcontroller embedded on the motherboard, acting as the intelligence in the IPMI architecture.
BOM Bill Of Materials
Boot Up The process of starting a computer. Booting up involves checking all hardware components, initializing system components, and loading the operating system.
bps Bits per second (example: 100bps)
Browser Software used for access to information on the World Wide Web.
BTU British Thermal Unit - A British standard unit of energy (heat output).
BW Bandwidth - This is a measure of the capacity of a communication channel, usually specified in MB/second.
Cache A buffer of high-speed memory filled at medium speed from main memory, often with instructions. A cache increases effective memory transfer rates and processor speed.
CAM Common Array Manager
CAP Cartridge Access Port - Allows one to input or remove tape cartridges from a library.
CDE Common Desktop Environment - A desktop for the Solaris Operating Environment (OE); this desktop was replaced with GNOME.
CD-ROM Compact Disc Read-only Memory - A medium for high-capacity data storage (approximately 600 Mbytes). Uses laser optics rather than magnetic capability to read data.
CE Correctable Error
See UE.
CEM Cartridge Expansion Module - Allows the addition of cartridge slots to a library.
CFW Cache Fast Write - Mainframe hosts can specify special attributes (example, cache fast write (CFW) command) to write data (typically a sort command) without write duplexing in the disk controller cache memory. This data is not duplexed and is usually given a discard command at the end of the sort, so that the data will not be destaged to the disk drives.
CGBU Oracle's Communications Global Business Unit
CHA Channel Adapter - Component in larger type disk arrays that allows data transfers between cache and the disk drives.
cHT Coherent HyperTransport - enhanced version of HT from AMD which enables Opteron processors to communicate within SMP systems via HT links.
(also known as cHT3 or cHT-3)
CIC Customer Intensive Care
CIFS Common Internet File System - An enhanced version of the SMB (see SMB) file-sharing protocol that allows groups of users to work together and share documents over the internet in the same way as in LANs (see LAN).
CLI CLI (command line interface) is a user interface to a computer's operating system or an application.
CMA Cable Management Arm
CMM Chassis Management Module (Sun Blade 6000/6048)
Chassis Monitoring Module (Sun Blade 8000)
CMT Chip MultiThreading - A ground-breaking technology that speeds processing by dedicating silicon and threads to network tasks. Compute, packet processing, and switching tasks run concurrently, not sequentially as in single threaded systems, resulting in dramatic increases in performance and system utilization.
CMU CPU/Memory Board Unit
CNA Converged Network Adapter - a network component that combines Fibre Channel HBA and Ethernet NIC functionality on the same adapter card in combination with one or more physical Ethernet ports. Utilized by FCoE technology.
COD Capacity On Demand
COMA Cache Only Memory Architecture - a computer memory design used in multiprocessors, where memory components at each node are used as cache, in contrast to using local memory as actual main memory (as in NUMA). Also called Cache Coherent NUMA (ccNUMA).
CompactPCI A computer system in which all boards are connected via a passive PCI backplane. Often shortened to cPCI.
Compression A procedure in which data is transferred by the removal of redundant information in order to reduce the number of bits required to represent the data.
cPCI See CompactPCI.
CPLD Complex Programmable Logic Device - A PLD with complexity between that of a PAL and an FPGA.
CPU Central Processing Unit - This is part of a computer (host) which controls all other parts of the system (might also be called processor).
CRM Customer Relationship Management - An information industry term for methodologies, software, and usually Internet capabilities that help an enterprise manage customer relationships in an organized way.
CRT Cathode-Ray Tube - This technology in used in television and computer display screens.
Note: Many computer manufacturers are using LCD (liquid crystal display) for monitors.
CRU Customer Replaceable Unit - Same as FRU, but orderable and replaceable by the customer.
CSB Centerplane Support Board
CSM Common Storage Module - These are expansion units (EUs) attached to a NAS appliance.
CTC Counter Timer Control - A programmable device that provides counting and timing functions.
CU Controller Unit - This abbreviation is normally used with a RAID CU in disk arrays.
CUP Control Unit Port - An administrative utility for switch networks
DAS Direct Access Storage - Storage directly attached to servers/hosts (as opposed to SAN storage where storage is attached to a network of storage devices).
DASD Direct Access Storage Device - This acronym is pronounced "DAZ-dee". It is a general term for disk storage historically used in the mainframe and minicomputer (mid-range) environments.
DAT Digital Audio Tape
dB Decibel - Is the measurement of a sound level; however, it is also used in electronics, signals and communication. It is a logarithmic unit used to describe a ratio.
DB Dual Bus - This is a configuration used in attaching disk arrays to a host; this configuration assigns half of the disk drives and their IDs to one channel, and the other half of the disk drives and IDs to the second channel.
DBMS Data Base Management System
DC Direct Current - This is electric current flowing in one direction only and substantially constant in value (as opposed to alternating current).
DDPM Dual Dynamic Power Management - the split power plane feature of AMD Opteron quad-core processors
DDR Double Data Rate - a class of memory module which achieves twice the bandwidth of single rate modules by transferring data on both the rising and falling edges of the clock signal without increasing the clock frequency. DDR memory used within systems includes DIMM and SIMM. See also QDR.
DEM Drive Expansion Module - Allows the addition of cartridge slots and drives to a library.
DFS Distributed File System - A file system that exists on more than one computer, enabling each user to access files on other computers.
DHCP Dynamic Host Configuration Protocol - This function provides a mechanism by which a computer can acquire an IP address automatically when it connects to the network. DHCP allows more flexible and efficient use of network resources than static IP addresses.
DIMM Dual In-line Memory Module - A small circuit (board/card) that holds memory chips (64-bit path).
DIP Switch A set of multisectioned toggle switches that have DIP geometry.
DLT Digital Linear Tape - This technology segments tape media into parallel, horizontal tracks, and records data by running the tape past a stationary head. DLT provides higher performance than helical scan technology.
DMA Direct Memory Access
DMP Dynamic Multipathing
DNS Domain Name System - This is a network service that translates domain names into IP addresses. This is a specific network server that maintains the list of all host names in a domain.
DOM Disk On Module - alternate term for FMOD
Domain A group of computers (hosts) and devices on a network that are adminstered as a unit with common rules and procedures.
DR Dynamic Reconfiguration - This function enables you to dynamically reconfigure, remove or install core system components into your Sun Fire server while the Solaris OE and your applications are operating.
DRAM Dynamic Random Access Memory - a type of memory (used in most personal computers) which must be refreshed constantly or it will lose its contents. See SRAM.
Driver A software program that enables a computer (host) to communicate with a peripheral device. Examples include Procom Technology's SCSI driver, CDROM driver, and printer driver.
DSA Digital Signature Algorithm - An encryption FIPS for digital signatures, developed for use in DSS. Often mentioned in conjunction with RSA.
DSP DSP can have one of the following meanings:
  • Digital Signal Processor - A computer oriented toward math-intensive applications, often a single chip or small chip set.
  • Data Services Platform - Normally used with the larger disk arrays.
DSS Digital Signature Standard - A digital signature standard developed by NIST.
DTQ Directory Tree Quota - A directory tree quota is a quota, or limit, to the space or the number of files that a directory tree (a directory and its subdirectories) can occupy.
DTU Desk Top Unit - Any unit that is a stand-alone system and can be placed in operational status on a desk or table type surface (normally small in size).
DVT Design Verification Test - The intensive test suite performed on a component under development, including functional/usability tests, climatic and reliability tests, safety and compliance tests, etc.
(See EVT and PVT)
DW Data Warehousing
Ecache External Cache (Same as L2 cache) - Memory cache external to the CPU chip.
ECC Error Correction Code - Extra bits added to Words, or Double Words, that correct all single-bit errors, and detect all double-bit errors.
EEPROM Electrically Erasable Programmable Read-only Memory - This acronym is pronounced as "double-ee-prom or e-e-prom." This type of memory can be erased with an electrical charge.
EIS Enterprise Installation Standards - a DVD-based image that provides comprehensive installation services for Sun products.
EISA Extended Industry Standard Architecture - A bus standard that maintains compatibility with the earlier ISA. EISA has a 32-bit data path and uses connectors that can accept ISA cards.
EM ExpressModule - a new form factor from QLogic for PCIe I/O adapters. PCIe ExpressModule defines hot-pluggable I/O modular form factors that enable PCI modules to be installed by sliding cartridges into external slots.
EOL End Of Life - Sun determines that the software product or hardware product will no longer be licensed or sold.
EOSL End of Service Life - EOSL is as follows:
  • The date on which Sun ceases to provide services for a Hardware Product or Software Product under a support contract or on a time and materials basis.
  • Sun documentation refers to EOSL by month and year, e.g. 7/03.
  • The last day of the applicable month is the EOSL date for a product.
EOV End of Version - Sun no longer licenses a specific version of a Software Product but continues to license new versions of the Software Product for sale.
ESCON Enterprise System Connection - An IBM protocol used to link mainframes with peripherals and other mainframes at 10-17 Mbps over fiber optic cable.
ESM Energy Storage Module - A backup electrical power source (such as a battery or capacitor) that supplies power to the main module in case of power interruption.
Ethernet 10/100/1000BaseT The most widely used LAN access method defined by IEEE 802.3 standard; uses standard RJ-45 connectors and telephone wire.
Note: The 100BaseT is also referred to as Fast Ethernet; the 1000BaseT is also referred to as Gigabit Ethernet.
EU Expansion Unit - A storage array that consists of a chassis with disk drives and I/O expansion modules. The EU does not include an I/O controller module; the EU connects to and is managed by a RAID array.
EVT Engineering Verification Test - The initial tests performed on component prototypes to verify that the design meets pre-determined specifications and design goals.
(See DVT and PVT)
F_port A port that supports an N_port on a Fibre Channel switch.
FAB Fabrication - The design and layout of a PCB.
Note: Refer to SunPWB Fabrication Specification 950-1009 for more information.
Fabric A group of interconnections between ports that includes a fabric element. A collection of switches and the connections between them.
Fast Ethernet Is the 100BaseT ethernet (100 bits per second).
Fast Write Allows disk write commands to be safely acknowledged to the host before the data is actually written to the disk media. This process can be enabled/disabled through the storage management software.
Fast/wide SCSI Data transfer rate of 20 MB/sec. Wide devices can be connected to a standard SCSI interface, but the extra data lines need to be terminated.
FATA Fibre Attached Technology Adapted - This is currently Hewlett-Packard (HP) technology that uses Seagate disk drives; they use 400GB and 500GB disk drives for high capacity.
FBDIMM Fully Buffered DIMM
FC Fibre Channel
FCAL Fibre Channel Arbitrated Loop - A fast serial bus interface standard (higher speed and increased distance between devices versus SCSI).
FCIP (also FC/IP) Fibre Channel over IP - This technology uses an IP-based storage networking standard to link data storage facilities. FCIP carries SCSI commands over IP networks but is restricted to use in FC technologies.
(See iSCSI)
FCode Forth Code - This term is a stack-based, extensible language without type-checking. It was invented in 1970 and is widely used within personal computers (high performance and economy of memory).
FCoE Fibre Channel over Ethernet - This proposed technology maps FC frames over selected full duplex IEEE 802.3 networks, allowing FC to leverage 10GbE networks while preserving the FC protocol.
FDDI Fiber Distributed Data Interface - This is a 100 Mbit/s ANSI standard local area network architecture.
FEM Fabric Expansion Module - resident in Constellation blades, allowing PCIe-based expansion similar to an HBA within the blade.
FGU Floating/Graphics Unit - also called Floating point [and] Graphics Unit
FICON Fiber Connection - Also known as Fiber Connectivity. Supports full duplex data transfers and enables greater throughput rates over longer distances.
FIPS Federal Information Processing Standards - Publicly announced standards developed by the U.S. Federal Government for use by all non-military government agencies and contractors.
Firmware This is software stored in ROM or PROM; firmware normally is responsible for a system's behavior when it first boots up.
FishWorks FISH = Fully Integrated Software and Hardware
a hardware/software solution designed to be used in supporting storage-oriented workloads.
flar Flash Archive - an image taken from a running system which can then be used to install other systems.
Flash Memory A special type of non-volatile solid-state memory that can be electrically erased and reprogrammed, making it far more economical than traditional memory DIMMs.
FLD Flash Drive
flops Floating Point Operations Per Second. The FLOPS is a measure of a computer's performance.
FMA Fault Management Architecture - component of Solaris that monitors, analyzes and proactively prevents system faults.
FMOD Flash Module - A component housing Flash memory.
(also known as DOM)
FPGA Field-Programmable Gate Array - A semiconductor device containing programmable logic components and programmable interconnects.
FRU Field Replaceable Unit - The smallest serviceable component by a field service engineer or equivalently trained personnel.
FTP File Transfer Protocol - A client-server protocol which allows a user on one computer to transfer files to and from another computer over a TCP/IP network.
Full-Duplex Data transmission in both directions at the same time. Also see "Half-Duplex" and "Simplex."
GA General Availability - Product is available for general shipment.
GB Gigabyte - Equals one billion bytes; a unit of computer memory or data storage capacity equal to 1,073,741,824 (230) bytes.
Gb Ethernet Gigabit Ethernet (GbE) - An ethernet standard that enables data transfer rates of up to 1 Gbps running over copper or fiber optical cable.
GBIC Gigabit Interface Converter - A standard form factor which provides a hot-pluggable connection into a Fibre Channel device.
Gbps Gigabit per second - This is a measure of bandwidth on a digital data transmission medium such as optical fiber (billions of bits per second).
GC Garbage Collection - the process of reclaiming memory taken up by unreferenced objects in an application
GEM Geographically Established Market
GNOME A desktop for the Solaris Operating Environment (OE).
GPIO General Purpose Input Output
GPU Graphics Processing Unit - a dedicated graphics rendering device
GRASP Graphics Redirect And Service Processor - assembly containing both Graphics Board and Service Processor in Galaxy systems
GTM Go To Market
GUI Graphical User Interface - A GUI uses graphical elements to present information to a computer user rather than the traditional text-only command line interface.
HA High Availability - Normally identifies a failover capability.
Half-Duplex Data transmission in only one direction at a time. Also see "Full-Duplex" and "Simplex."
HASRAM High Availability SRAM
HBA Host Bus Adapter - A card that enables a host (server) to connect to a peripheral device.
HCA Host Channel Adapter - See IB-HCA.
HDD Hard Disk Drive
HH Half Height
Hot Plug Hot-pluggable components are components that you can install or remove while the system is running, without affecting the rest of the system's capabilities. However, in many cases, you must prepare the operating system prior to the hot-plug event by performing certain system administration tasks.
Hot Spare Drive(s) within a storage system held in reserve to replace any other drive when it fails.
Hot Swap Hot-pluggable components that require no such preparation are called hot-swappable components. These components can be removed or inserted at any time without preparing the operating system in advance. While all hot-swappable components are hot-pluggable, not every hot-pluggable component is hot-swappable.
HPC High Performance Computing - refers to the use of parallel supercomputers and computer clusters, i.e. computing systems comprised of multiple (usually mass-produced) processors linked together in a single system with commercially available interconnects. Recently, HPC has come to be applied to business uses of cluster-based supercomputers, such as data warehouses, line-of-business (LOB) applications and transaction processing. See also HPTC.
HPTC High Performance Technical Computing - refers to the engineering applications of cluster-based computing, such as computational fluid dynamics, simulation, modeling, and seismic tomography (particularly in the petrochemical industry). See also HPC.
HSM Hierarchical Storage Management - A method for keeping infrequently used data in secondary storage, then restoring it automatically when a user calls for the data.
HT see HyperTransport.
HTML Hyper-text Markup Language - A document format used on the world-wide web.
hsPCI Hot Swap PCI.
HTTP Hyper-text Transmission Protocol - A protocol for exchanging HTML pages and forms.
HTTPS Hyper-text Transmission Protocol over SSL - A protocol using HTTP with additional encryption layers.
Hub A dedicated bandwidth device for connecting fibre cables.
HVD High Voltage Differential - A method of driving data over SCSI cables (used for years); HVD uses 5 VDC whereas LVD (Low Voltage Differential) uses 3.3 VDC.
HyperTransport a bidirectional serial/parallel high-bandwidth, low-latency point-to-point link used by (among others) AMD in its x86 processors. Version 3.0 (known as HT3 or HT-3) has a 2.6GHz maximum frequency.
I2C (I2C) Inter-Integrated Circuit - A simple bi-directional 2-wire bus for efficient inter-IC control. This bus is called the Inter-IC or I2C-bus.
IB-HCA InfiniBand Host Channel Adapter - A switched fabric communications link primarily used in high-performance computing.
IBB Install Base Business (Marketing Group)
IBTA InfiniBand Trade Association - Comprised of leading enterprise IT vendors including Agilent, Dell, Hewlett-Packard, IBM, InfiniCon, Intel, Mellanox, Network Appliance, Oracle, Sun, Topspin and Voltaire.
IC Integrated Circuit - An IC (sometimes called "chip") is a microelectronic semiconductor device consisting of many interconnected transistors and other components.
IDE Integrated Drive Electronics - An older term for the ATA interface.
IDPROM IDentification PROM - on older machines, the component that stored the HostID and Ethernet addresses of a system.
Sometimes the term is used to refer to the addresses themselves, rather than the component that stores them (as in "IDPROM data").
Occasionally referred to as SSCC.
IEEE Institute of Electrical and Electronics Engineers - An international non-profit professional organization for the advancement of electronics technology, which sets standards in many industries including Information Technology and telecommunications.
IETF Internet Engineering Task Force - An open standards organization with voluntary participation from the technology industry.
ILOM Integrated Lights Out Management - Used for remote management of servers (has a dedicated service processor); also see ALOM.
IMPI Intelligent Platform Management Interface - An open standard for monitoring, logging, recovery, inventory, and control of hardware that is implemented independent of the main CPU, BIOS, and OS.
InfiniBand A high performance, switched fabric interconnect standard for servers.
Initiator Typically a server or workstation that initiates transactions to disk or tape targets.
I/O Input/Output - Transferring data between the CPU and any peripherals. Normally measured in operations per second.
IOPS Input/Output Operations Per Second - A measure of I/O performance usually used to quote random I/O performance.
I/O rate A measure of a device capacity to transfer data to and from another device within a given time period, typically as I/O operations per second.
IP Address Internet Protocol Address - A unique 32-bit value that identifies network hosts using TCP/IP. No two network hosts can be assigned the same IP address.
IPMB Intelligent Platform Management Bus/Bridge - In IPMI implementations, the bus/bridge that connects the BMC to controllers within the same chassis (an enhanced implementation of I2C).
(See IPMC)
IPMC Intelligent Platform Management Chassis - In IPMI implementations, the bus/bridge that connects the BMC to controllers in a remote chassis.
(See IPMB)
IPMI Intelligent Platform Management Interface - An open standard used for monitoring and control of hardware that is implemented independent of the main CPU, BIOS, and OS (most commonly implemented on x64/x86 platforms).
ISA Industry Standard Architecture - This is a bus standard for IBM compatibles that extend the bus architecture to 16 bits.
iSCSI Internet SCSI (Small Computer System Interface) - This technology uses an IP-based storage networking standard to link data storage facilities. iSCSI carries SCSI commands over any existing IP networks.
(See FCIP)
ISP Internet Service Provider - A company that provides other companies (or individuals) with access to the Internet.
ISV Independent Software Vendor - Software only, not a hardware manufacturer.
ITU Install Time Update - The Driver Update diskette, sometimes called an Install Time Update (ITU), is a medium through which users can add new and updated device drivers to an off-the-shelf version of Solaris.
Java Is a programming language developed by Sun Microsystems to be portable to any type of computing device.
JBOD Just a Bunch of Disks - A storage array with independent disk drives. Software RAID would have to be used for any data protection.
JFS Journaling File System - A fault-resilient file system in which data integrity is ensured because updates to directories and bitmaps are constantly written to a serial log on disk before the original disk log is updated.
Jiffy Bracket A type of disk drive mounting bracket. Refer to the Mounting Hardware page for more details.
JTAG Joint Test Action Group - An IEEE standard for serial scanning of chip internal registers.
Kb Kilobit - Equals one thousand bits; a unit of computer memory or data storage capacity equal to 1,024 (210) bits.
KB Kilobyte - Equals one thousand bytes; a unit of computer memory or data storage capacity equal to 1,024 (210) bytes.
KMA Key Management Appliance - any of the devices serviced by KMS.
KMS Key Management Station - Data encryption system for tape drives, which centrally authorizes, secures and manages encryption keys.
Also known as Crypto KMS.
KVMS A series of interfaces that enables a system to respond to keyboard, video, mouse, and storage events.
kVa Kilovolt ampere - A unit of power.
L2 Cache Same as Ecache (External cache) - Memory cache external to the CPU chip.
L2ARC Level 2 ARC - ZFS technology which extends main memory cache with fast storage devices such as SSDs to improve read performance. Works in conjunction with ZIL.
LAN Local Area Network - A communications network that provides high-speed (over 1Mbps) data transmission and is limited to a specific physical area (up to about six miles).
LCA Low Cost Array
LCD Liquid Crystal Display - A type of display used in digital watches and many computer devices. This technology uses two sheets of polarizing material with a liquid crystal solution between them.
LCU Library Control Unit
LD Logical Drive - A group of physical drives configured with a RAID level. Each logical drive can be configured for a different RAID level.
LDAP Lightweight Directory Access Protocol
LDEV Logical Device - a device connected to a host, identified by a LUN.
LDoms Logical Domains - LDoms technology allows a user to allocate a system's various resources, such as memory, CPUs, and devices, into logical groupings and create multiple, discrete systems, each with their own operating system, resources, and identity within a single computer system.
LED Light Emitting Diode - A type of diode that emits light when current passes through it.
Linux A UNIX-like operating system, one of the most prominent examples of free software and open source development.
LMU Library Management Unit
LOD Last Order Date - The last day a customer can order a unit (system).
Longwave GBIC Gigabit Interface Converter (GBIC) designed for transmission of data over long (10km) distances.
LP Low Profile
LPC Low Pin Count
LRU Least Recent Used. See MRU.
LSD Last Ship Date - The date that Sun ceases to ship the Hardware Product, a specific version of a Software Product, or the Software Product, as indicated in the EOV or EOL announcement issued by Sun.
LSM Library Storage Module
LTO Linear Tape-Open - This type of tape storage is basically an open-format tape storage technology developed by Hewlett-Packard (HP), International Business Machines (IBM), and Certance. It is also known as LTO Ultrium format.
LUN Logical Unit Number - A numbering sequence for logical devices (LDEVs) connected to a host.
LUSE Logical Unit Size Expansion - method used to create Logical Devices (LDEVs) larger than the standard device emulations. LUSE concatenates numerous LDEVs into a single larger LDEV, which is then presented to the host as a single LUN.
LVD Low Voltage Differential - A method of driving data over SCSI cables; LVD uses 3.3 VDC whereas HVD (High Voltage Differential) uses 5 VDC. LVD is less expensive and allows higher transfer speeds.
MAC Media Access Control (MAC address) - also known as "Ethernet address" or "physical address" - the hardware-encoded network address that uniquely identifies a piece of network hardware.
MAID Massive Array of Idle Disks - a system using hundreds to thousands of hard drives for near-line data storage. Each drive is only spun up on demand as needed to access the data stored on that drive.
MAL Minimum Acceptable Level
MAU Modular Arithmetic Unit - An on-chip component in CoolThreads processors, driven by the NCP driver to offload and accelerate encrypted operations without compromising performance of the regular core functionality.
MB Megabytes - Equals one million bytes; a unit of computer memory or data storage capacity equal to 1,048,576 (220) bytes.
Mbps Megabits per second - Measurement of data tranmissions.
MCA Machine Check Architecture - feature of Intel processors (now also standard in AMD processors) by which the CPU reports hardware errors to the operating system.
MCU Memory Control Unit
MD1/MD2 There are two defined card lengths for low profile PCI 2.2: MD1 and MD2.
MD1 defines the shortest 32-bit card length available (121.79 mm) and MD2 defines the maximum card length of 169.52 mm and can accommodate 32-bit or 64-bit PCI Bus connector standards.
MHz Megahertz - A measurement of frequency equivalent to 1 million cycles per second.
MIB Management Information Base - A collection of objects in a virtual database used to manage entities for SNMP.
Micron An obsolete metric unit, = 10-6 meter. The term is still commonly used in certain fields, including semiconductor fabrication.
MIME Multipurpose Internet Mail Extensions - This is the standard for common data formats like GIF, JPEG, TIFF, PDF, and so on.
Mirror To duplicate data from a primary location to a secondary location, so that the data is still available if the primary location fails (normally called RAID 1 in disk arrays).
Mirrored Cache Redundant copies of data residing in cache - The write cache data residing in cache which has not yet been written to the hard disks is duplicated for failover operation.
Mirroring (RAID) Redundant storage of data, achieved by duplicating files (so there is always a primary file and a copy of the primary file) onto separate disks.
MLC Multi-Level Cell - a memory element capable of storing more than a single bit of information by using multiple cell levels.
See SLC.
MLF2 Molded Quad Flat No Lead Package
MMF MultiMode Fiber - MMF uses optical fiber to carry multiple light rays or modes concurrently.
Note: MMF is normally used for relatively short distances. Single mode fiber (known as monomode) is used for longer distances.
MMU Memory Management Unit - a hardware component responsible for handling accesses to memory requested by the CPU.
Motherboard A large circuit board that contains the computer's (host's) central processing unit (CPU), microprocessor support chips, random-access memory (RAM), and expansion slots.
MPIO MultiPath I/O - a fault-tolerance and performance enhancement technique whereby there is more than one physical path between the CPU in a computer system and its mass storage devices through the buses, controllers, switches, and bridge devices connecting them.
MPO Memory Placement Optimization - technology in Solaris to keep NUMA informed of memory and processor placement for improved performance.
MPxIO Multiplexed I/O - architecture integrated into Solaris, that enables I/O devices to be accessed through multiple host controller interfaces from a single instance of the I/O device.
MRU Most Recent Used. See LRU.
MSP Master Service Processor - Storage service processor that acts as the point of aggregation for a network of storage service processors.
MTBDL Mean Time Between Data Loss - In a RAID system, this is the average expected time between two rapid disk failures that would cause irreparable data loss (unless RAID 6 is being used).
MTBF Mean Time Before Failure - The average time a component works without failure.
MTTR Mean Time To Repair - The average time it takes to repair a failed component.
Multipathing The ability to manage two or more physical or logical paths to a given target or device.
N_Port A Fibre channel port in a point-to-point or fabric topology.
Nanometer See nm.
NAR Narrow Aisle Removal
NAS Network Attached Storage - This is normally a NAS appliance with applicable expansion units (EUs) attached as the storage modules.
NCP Niagara Crypto Provider - A device driver in Solaris 10, which works with CoolThreads processors to increase the speed and efficiency of encrypted throughput.
N2CP Niagara2 Crypto Provider - Update of the NCP driver for the Niagara2 processor.
NCQ Native Command Queuing
NDMP Network Data Management Protocol - This technology uses an open protocol to control data backup and recovery communications between primary and secondary storage in a heterogeneous network environment.
NEBS Network Equipment-Building System - NEBS describes the environment of a typical Regional Bell Operating Company (RBOC) Central Office (CO). NEBS is the most common set of safety, spatial and environmental design guidelines applied to telecommunications equipment in the United States. See TCG.
NEM Network Express Module
NEMA National Electronic Manufacturers Association - a standards-setting body for many industries including the data industry.
NetBIOS Network Basic Input/Output System - This is a protocol used for networking. NetBIOS was designed to support communications between symbolically named stations and the transfer of arbitrary data.
Network An arrangement of nodes and connecting branches, or a configuration of data processing devices and software connected for information exchange.
NFS Network File System - Sun-created file system allowing a client computer to access files over a network as easily as if the network devices were attached to its local disks.
NIC Network Interface Card - A card that provides a host access to the network.
NIST National Institute of Standards and Technology - a non-regulatory agency of the U.S. Department of Commerce, which publishes a wide variety of standards on many topics including technology.
NL_Port A port attached to a node for use in all thre topologies (point-to-point, arbitrated loop, or fabric).
nm nanometer - unit of measurement used to describe the wavelength of light (equal to one billionth of a meter).
Node A device that has at least one N_Port or NL_Port.
NPI New Product Introduction
NPIV N_Port ID Virtualization - a Fibre Channel facility allowing multiple N_Port IDs to share a single physical N_Port.
NSV Network Share Volume - a CD-ROM (or CD image) containing supplementary software tools and packages such as diagnostics and device drivers.
NTC Network Terminal Concentrator - A modem connection point for Sun Storage Remote Response offering Helps facilitate a point-to-point connection from a remote support center.
NTP Network Time Protocol - NTP provides a mechanism for synchronizing the time among a number of computers connected to a network.
NUMA Non-Uniform Memory Access - a computer memory design used in multiprocessors, where memory access time depends on the memory location relative to a processor (implemented in modern computers whose CPUs run faster than memory). See COMA and MPO.
NVRAM Non-Volatile Random Access Memory - a type of memory that retains its contents when power is turned off.
NVSRAM Non-Volatile Static Random Access Memory - a type of SRAM memory that retains its contents when power is turned off.
OEM Original Equipment Manufacturer
OKM Oracle Key Manager
OLTP On-Line Transaction Processing
OpenSSL Open source implementation of SSL and TLS, available for most UNIX-like operating systems.
OPL Olympus Product Line - midrange & high-end SPARC64-VI platforms, partnered with Fujitsu
Optical Fiber Any filament of fiber, made of dielectric material, that guides light.
OS Operating System
Out-of-band Transmission of a management protocol outside of the Fibre channel network, typically over Ethernet.
OVM Oracle Virtual Machine
PAL Programmable Array Logic - A term used to describe a family of PLD semiconductors used to implement logic functions in digital ciurcuits.
Parity In an array environment, data that is generated from user data and is used to regenerate user data lost due to a drive failure.
Parity error handling This refers to the processing of the data when the parity does not match the data sent, signifying an error condition.
Partition Sections on a LUN. Each partition can either have some space allocated to it, or can be empty.
Partner Group Sometimes called a partner pair. Two controller units providing redundant data and management paths, and mirrored cache duplexing (which provide controller failover and path failover capability).
PATA Parallel ATA - see ATA.
Path Failure This occurs when an I/O to a unit is interrupted for any reason other than for a controller failure (such as, a bad cable, host adapter, or an non-I/O root cause such as removal of an application host system I/O board.
PB Petabyte - Equals one thousand terabytes (1,024 terabytes); a unit of computer memory or data storage capacity equal to 1,125,899,906,842,624 (250) bytes.
PCB Printed Circuit Board
PCBA Printed Circuit Board Assembly
PCI Peripheral Component Interconnect - a computer bus for attaching peripheral devices to a computer motherboard.
PCI-E / PCIe / PCI Express Peripheral Component Interconnect Express - Formerly known as third generation I/O, this implementation of the PCI computer bus that uses existing PCI programming concepts and communication standards, but bases it on a much faster serial communications system.
PCI-X Peripheral Component Interconnect-eXtended - A computer bus technology that increases the speed that data can move within a computer from 66 MHz to 133 MHz.
PDB Power Distribution Board - Used in many systems to distribute power (AC & DC) to other components.
PDU Power Distribution Unit - Used in many systems to distribute power (AC & DC) to other system components.
PFA Predictive Failure Analysis - Allows individuals to review a report and identify a potential failing component.
PHY Physical - This is a generic electronics term refering to a special electronic integrated circuit or functional block of a circuit that provides physical access to a digital connection cable.
PICMG PCI Industrial Computer Manufacturers Group - A consortium of over 450 companies that collaboratively develop open specifications for high performance telecommunications and industrial computing applications.
PLCC Plastic Leaded Chip Carrier
PLD Programmable Logic Device - An electronic component used to build reconfigurable digital circuits, with no defined function at the time of manufacture. The PLD must be programmed before it can be used in a circuit.
PMC PCI Mezzanine Card - a PCB compatible with the PCI bus but smaller than standard PCI cards, inserted between two adjacent host cards. Often used in CompactPCI systems.
POD Ports On Demand - A switch technology that allows a user to activate the licensing for additional ports on his switch as they are needed.
Point-to-Point A topology where exactly two ports communicate.
Port An access point on a device for attaching a link.
POSIX Portable Operating System Interface for UniX - The collective name of a family of related standards specified by the IEEE to define the programming interfaces for variants of the Unix operating system.
PROM Programmable Read-Only Memory - This is ROM which can be written using a PROM programmer.
Protocol A convention for data transmission that defines timing, control, format, and data representation.
PSB Physical System Board - The physical system board, as opposed to logical counterparts into which it can be partitioned.
See also XSB, Uni-XSB, Quad-XSB.
PSU Power Supply Unit
PTP Pass Through Port
PVT Production Verification Test - Tests to verify that a system (or a component within that system) operates in the expected manner from an end-user and operator perspective, principally to determine the supportability of the product.
(See DVT and EVT)
PWB Printed Wiring Board
PXE Short for Pre-Boot Execution Environment. Pronounced pixie. PXE is an environment to bootstrap computers using a network interface card independently of available data storage devices (like hard disks) or installed operating systems (like GNU/Linux).
QDR Quad Data Rate - a class of memory module that can transfer up to four words of data in each clock cycle. Like DDR, QDR transfers data on both the rising and falling edges of the clock signal, but QDR uses two clocks, one for read data and one for write data.
QFS A high performance file system for Solaris environments designed to solve file system bottlenecks by maximizing file system throughput in conjunction with the underlying disk technology and storage hardware.
Quad-XSB A PSB that is logically divided into four boards.
See also PSB, XSB, Uni-XSB.
Quiesce To slow down the computer or make one of its resources inactive, but still available, in order to conserve power. The term comes from "quiescent," which means "to become quiet."
QSFP Quad Small Form-factor Pluggable - product line (including cages, connectors, and cable assemblies) which offers three times the density of SFP and can support speeds up to 10 Gb/second per channel.
RAID Redundant Array of Independent Disks - A set of disk drives which appear to be a single logical disk drive to an application, such as a database or file system. Different RAID levels provide different capacity, performance, availability, and cost characteristics.
RAID 0 Non-redundant striped array.
RAID 1 Mirrored arrays.
RAID 1+0 Mirrored and striped array (might see it as RAID 1/0).
RAID 2 Parallel array with ECC.
RAID 3 Parallel array with parity.
RAID 4 Striped array with parity.
RAID 5 Striped array with rotating parity (allows an array to function with one failing disk).
RAID 6 Block-level striping with dual distributed parity (allows an array to function with two failing disks).
RAIN Redundant Array of Independent Nodes
RAM Random Access Memory - This is the physical memory that is internal to the computer (host). It is sometimes called main memory.
RAS Reliability, Availability, and Serviceability
RCCOM Redundant Controller Communication - Provides the communication channels by which two controllers in a redundant RAID array communicate with one another.
RDAC Redundant Disk Array Controller - The RDAC driver is included in the RAID Manager software, and manages the rerouting of active I/O operations when a controller fails.
RDMA Remote Direct Memory Access - A technology that allows data to move directly from the memory of one computer into that of another without involving either one's operating system.
Read-ahead Sequential data read from disk into cache without having actually been requested by the application host, in anticipation that it will be requested by the host.
Reconstruction The process used to restore a degraded RAID 1, 3, 5, or 6 LUN to its original state after replacing a failed drive.
REM RAID Expansion Module
  • Request For Change - a generic term in the technology industry
  • Request For Comments - a series of memoranda on Internet technical issues. The IETF adopts some RFCs as Internet standards.
RFID Radio Frequency IDentification - A technology that allows remote identification of a product by the insertion of an electronic tag that can be read by radio waves.
RHEL Red Hat Enterprise Linux - a Linux distribution produced by Red Hat Inc. and targeted toward the commercial market.
RIA Rich Internet Application - a Web application that has the features and functionality of traditional desktop applications. RIAs typically run in a Web browser and transfer user interface processing to the web client while keeping the bulk of the data on the application server.
RISC Reduced Instruction Set Computer - a CPU design based on the theory that simplified instructions that do less can provide faster execution.
RJ45 Registered Jack - RJ45 is a term commonly used to refer to any 8P8C modular connector.
RKVMS Remote Keyboard, Video, Mouse, Storage. Allows redirection of the server keyboard, video output, mouse and storage devices via a networked system.
RME Removable Media - You might find this term used as follows:
  • Identifying any object and/or device that can store data (example, tape drives, CD-ROMs, DVD-RW, and so on)
  • Specifying a reference to an assembly (example, removable media tray, removable media assembly, removable media key switch, and so on)
RNG Random Number Generator
RO Read-Only
RoHS Restriction of Hazardous Substances - It is a Directive enacted in the European Union (EU) Parliament February 2003.
  • RoHS bans the sale of certain electronic equipment containing these materials in the EU:
    Lead, Mercury, Hexavalent Chromium, Cadmium, and certain brominated flame retardants
  • All 25 EU nations are currently enacting their own legislation in support of the Directive.
  • Implementation date: 7/01/06
  • Lead in solders is exempt in some Sun products: servers, storage arrays, and network infrastructure.
RoHS:Y Based on present information and belief, this equipment/part number complies with the European Union RoHS Directive, 2002/95/EC, and amending and guidance documents, and does not contain any restricted substances above the homogeneous materials' maximum concentration values, except for selected exemptions allowed by law (EXCLUDING the exemption for lead in solders for servers, storage and storage array systems, network infrastructure equipment for switching, signaling, transmission as well as network management for telecommunications).
RoHS:YL Based on present information and belief, this equipment/part number complies with the European Union RoHS Directive, 2002/95/EC, and amending and guidance documents, and does not contain any restricted substances above the homogeneous materials' maximum concentration values, except for selected exemptions allowed by law (INCLUDING the exemption for lead in solders for servers, storage and storage array systems, network infrastructure equipment for switching, signaling, transmission as well as network management for telecommunications).
RoHS-5 RoHS-5 is used by Sun and is defined by Sun as: RoHS-5 equals the RoHS:YL definition.
RoHS-6 RoHS-6 is used by Sun and is defined by Sun as: RoHS-6 equals the RoHS:Y definition.
ROM Read-Only Memory - This is computer (host) memory on which data has been prerecorded (written data cannot be removed from the chip).
Note: RAM is is faster than ROM; some manufacturers have their BIOS copied from ROM to RAM when the system is booted up (shadowing).
RR Revenue Release - Product is available for limited shipment.
RSA An algorithm for public-key cryptography, widely used in electronic commerce protocols. Its name derives from the initials of the originators of the algorithm at MIT (Rivest, Shamir, Adleman). Often mentioned in conjunction with DSA.
RSC Remote System Control - Provides enhanced features and Ethernet access for applicable systems (servers/hosts)
RTC Real Time Clock - This is a clock that keeps track of the time even when the computer is turned off. Do not confuse the RTC with the CPU clock (regulates the execution of instructions)
RTM Rear Transition Module
RTS Redundant Transfer Switch
RTU Redundant Transfer Unit
RU Rack Unit - The modular unit "U" on which panel heights are based is 1.750 inches (44.45mm).
  • 1U: One rack unit which equals 1.750 inches (44.45mm). Also called 1RU.
  • 2U: Two rack units which equals 3.5 inches (88.9mm). Also called 2RU.
RW Read-Write
SAF-TE SCSI Accessed Fault-Tolerant Enclosures
SAM-FS Storage and Archive Management-File System - A high performance, 64-bit Solaris file system and volume manager.
SAN Storage Area Network - An advanced storage option to deploy centrally pooled storage. SAN technology provides a variety of business and technical advantages over current disk attachment and data storage architectures.
SAS Serial Attached SCSI - a computer bus technology primarily designed for transfer of data to and from devices like hard drives. Designed for the corporate and enterprise market as a replacement for parallel SCSI, allowing for much higher speed data transfers than previously available. Marketed for critical server applications, it is faster and more versatile than SATA.
SATA Serial Advanced Technology Attachment - a computer bus primarily designed for transfer of data between a computer and storage devices (like hard disk drives or optical drives). Designed as a successor to the legacy Advanced Technology Attachment standard (ATA). See also PATA
SB Single Bus - This is a configuration used in attaching disk arrays to a host; this configuration assigns all of the disk drives and their IDs to one channel. This configuration allows the user to assign all RAID controller drive array drive IDs to Channel 0, and assigns all expansion array drive IDs to Channel 2.
SC System Controller
SCC System Configuration Card
SCI Scalable Coherent Interface
SCSI Small Computer Systems Interface
SCSI Address The octal representation of the unique address (0-7) assigned to a narrow device; or hex representation of the unique address (0-15) assigned to a wide SCSI device.
SCSI ID Small Computer Systems Interface Identification - This is the priority number (address) of a SCSI device in a SCSI device chain. Only one device at a time can transmit through a SCSI connection (port), and priority is given to the device with the highest address. Each address (ID) on a chain must be unique (no duplication).
SDI System Data Interface - An ASIC which connects data switches to system boards.
SEEPROM Serial Electrically Erasable Programmable Read-only Memory - This technology uses an EEPROM chip (smaller & less power) for a serial interface to the applicable circuit card.
SESI An abbreviation of two product codenames: SEbring and SIlverstone.
SFF Small Form-Factor
SFP Small Form-Factor Pluggable - A compact optical transceiver used in optical communications for both telecommunication and data communications applications.
SIA Sun Installation Assistant
SIM Service Information Message - System messages from normally the larger units identifying a problem.
SIM SAS Interface Module
SIMM Single In-line Memory Module - A small circuit (board/card) that can hold a group of memory chips (32-bit path).
Simplex Data transmission in one preassigned direction only. Also see "Full-Duplex" and "Half-Duplex."
SLA Service Level Agreement
(or Software License Agreement)
SLC Single-Level Cell - a memory element capable of storing only one bit of information in a cell.
See MLC.
SLES SUSE Linux Enterprise Server - a Linux distribution supplied by Novell Inc., targeted at the business market. SLES receives much more intense testing than other SUSE Linux products.
SMB Server Message Block - A Microsoft-compatiable network protocol for exchanging files. SMB is typically used by Windows for Workgroups, OS/2 Warp connect, and DEC Pathworks.
SMBus System Management Bus
SME Storage Media Encryption
SMP Symmetric Multiprocessing - This type of architecture uses two or more processors to share main memory. This technology allows tasks to be shared between processors to balance the workload efficiently.
SMS System Management Services - software application for controlling and monitoring domains.
SMTP Simple Mail Transfer Protocol - This is a TCP/IP protocol used in sending and receiving e-mail.
SNDR StorEdge Network Data Replicator
SNEEP Serial Number in EEPROM - This tool stores serial numbers and other critical information in a safe manner that persists across system software installations. It provides easy access to the serial number from the Solaris shell as well as from the OBP. Also see infodoc 81619, Serial Number in EEPROM (SNEEP) Tool, for more information.
SNIA Storage Networking Industry Association - A non-profit organization made up of over 400 member companies, dedicated to advancing IT technologies, standards and education relating to storage and information management.
SNMP Simple Network Management Protocol - SNMP is primarily used for network monitoring and notification of network errors and other events.
SOA Service-Oriented Architecture
SP Support Processor - can also be referred to as System Processor or Service Processor (depending on system and documentation).
SPARC Scalable Processor ARChitecture - a microprocessor standard implemented in processors used in a range of computers from laptops to supercomputers
SPU Streams Processing Unit - a component of the CoolThreads processor cores, offering Encryption/Decryption and Hash-Operations offload engine, which can be used to offload encrypted operations.
Spud bracket Storage Pedestal Upgrade Drive bracket - A type of disk drive mounting bracket. Refer to the Mounting Hardware page for more details.
SRAM Static Random Access Memory - a type of memory that does not need to be refreshed regularly like DRAM, but is consequently more expensive and requires more power.
SSCC Socketed System Configuration Chip - see IDPROM.
SSD Solid State Drive - a data storage device that uses solid-state memory to store persistent data. An SSD emulates a conventional hard disk drive, thus easily replacing it in any application.
SSL Service Support Life
SSL Secure Sockets Layer - A cryptographic protocol that provides secure communications on the Internet. Slightly different but essentially identical to TLS.
SSP System Service Processor - Also know as SVP (Service Processor). The management device integrated into storage systems that provides unified management access to system components and remote management functionality.
Striping This is a RAID-based method for data storage in which a single drive is designated to store error-correction (or parity) data, with the remaining drives in an array used to record sequential, smaller-sized portions of data.
Note: Normally RAID 3 uses one drive for parity; RAID 5 stripes parity and the data on its drives.
SUE Solaris Utility Environment - a Solaris image that can be used on customer systems to perform a vareity of diagnostic and maintenance functions.
SUSE Software- Und System-Entwicklung (German: Software and System Development) - a major Linux distribution produced in Germany by Novell Inc.
SUSE is also a founding member of the Desktop Linux Consortium.
SVP Service Processor - Also know as SSP (System Service Processor). The management device integrated into storage systems that provides unified management access to system components and remote management functionality.
SWaP Space, Watts, and Performance - CoolThreads technology that provides unsurpassed performance and efficiency (examples, Sun Fire T1000 and T2000 server technology).
TAA Trade Agreements Act - legislation that requires Government purchases over a certain price threshold to be certified as "U.S.-made or designated country end products". The legislation defines a broad array of "designated countries" from which purchases are TAA-certified.
TB Terabyte - Equals one thousand billion bytes (1000 Gigabytes); a unit of computer memory or data storage capacity equal to 1,099,511,627,776 (240) bytes.
TBBU Transportable Battery Backup Unit
TCG Two relevant definitions:
1. Trusted Computing Group - This organization develops and promotes open specifications.
2. Telecommunications Carrier Group - a coalition of telco carriers (AT&T, Verizon, Qwest, etc.) that set NEBS standards.
TCPA Trusted Computing Platform Alliance
TCP/IP Transmission Control Protocol/Internet Protocol - A commonly used networking protocol that allows interconnection of different network operating systems.
Telnet A terminal emulation program for TCP/IP networks.
teraflop A teraflop is a measure of a computer's speed and can be expressed as:
  • A trillion floating point operations per second
  • 10 to the 12th power floating-point operations per second
  • 2 to the 40th power flops
Termination The electrical connection at each end of the SCSI bus, composed of a set of resistors on internal SCSI devices or an active or passive SCSI terminator block on external SCSI devices.
TLS Transport Layer Security - see SSL
TOD Time Of Day - the clock chip on most system boards
TOE TCP Offload Engine - A technology used in NICs to offload processing of the entire TCP/IP stack to the network controller.
TOI Transfer Of Information
TOR Top Of Rack
TP Twisted Pair - The use of ordinary copper wire that connects home and many business computers to the telephone company. This technology reduces crosstalk or electromagnetic induction between pairs of wires; basically, two insulated copper wires are twisted around each other.
Note: This technology can use two or more twisted pairs within a single cable (due to multiple connection requirements).
TPM Trusted Platform Module - This term is used in system block diagrams.
Transfer Rate The rate at which data is transferred, usually measured in megabytes per second (MB/sec).
TSS TCG (Trusted Computing Group) Software Stack
TSSOP Thin Shrink Small Outline Package
Twinax Twinaxial Cable - cable similar to coaxial but with two inner conductors intead of one. Becoming common in modern very-short-range high-speed differential signaling applications.
UE Uncorrectable Error
See CE.
UFS UNIX file system
UIM Unit Information Module
Ultra320 SCSI A standard for SCSI data transfers. It allows a transfer rate of up to 320 MBytes/sec over a 16-bit SCSI bus.
Unicode This is a standard for representing letters that allows the language of computer messages and commands to be displayed in a variety of languages without rewriting the underlying programs.
Uni-XSB A PSB that is logically divided into only one board (i.e. undivided status).
See also PSB, XSB, Quad-XSB.
UPS Uninterruptible Power Supply
URL Uniform Resource Locator - An address system used by servers and clients to request documents. See IP address.
USB Universal Serial Bus - This is an external standard interface cable for communication between a computer (host) and peripherals (such as, keyboards, mice, monitors, printers, and so on).
USP Universal Storage Platform - An enterprise-class storage system from Hitachi which combines standard storage technology with storage virtualization (see UVM).
UTP Unshielded Twisted Pair - UTP is the most common kind of copper telephone wiring; this technology uses ordinary copper wire that connects home and many business computers to the telephone company. This design reduces crosstalk or electromagnetic induction between pairs of wires; basically, two insulated copper wires are twisted around each other. UTP is also used in many electronic systems.
Note 1: This technology can use two or more twisted pairs within a single cable (due to multiple connection requirements).
Note 2: Each pair is uniquely color coded when it is packaged in multiple pairs. Different uses such as analog, digital, and Ethernet require different pair multiples.
UVM Universal Volume Manager - A tool from Hitachi which enables storage virtualization, allowing the presentation of externally connected storage from multiple vendors through a USP.
VCS Veritas Cluster Server
VGA Video Graphics Array
VIM Vendor Interface Module - a component in a XAM library designed to interface with a specific vendor's storage devices.
VLP Very Low Profile
Voltage Formula is current x resistance = Voltage (I x R = E)
Volume A volume is a virtual disk into which a filsystem, a DBMS, or an application can place data.
VPN Virtual Private Network - Allows connection of both branch offices and telecommuters into an enterprise-wide corporate network via the Internet.
VRM Voltage Regulator Module - electronic device that provides a microprocessor the appropriate supply voltage.
VSM Virtual Storage Manager - Hardware/Software system for interfacing servers and tape storage
VTL Virtual Tape Library
Warm Plug The ability to remove, replace, or add a device while power is still applied, but all I/O processes are supended.
Wavelength The measured distance between one peak of a wave of light, heat, or other energy and the next corresponding peak.
WINS Windows Internet Naming Service - A WINS server resolves NetBIOS names to IP addresses, allowing computers on a network to locate other NetBiOS devices more quickly and efficiently. WINS performs a similar function for Windows environments as DNS does for the Unix environments.
WWN World Wide Name - This is an identification of a 64-bit address used in fibre channel networks to uniquely identify each element in a Fibre Channel network.
WWWW What Works With What
XAM eXtensible Access Method - a specification from SNIA that describes an architecture defining a standard access method between software and storage devices to manage fixed content storage systems.
XAUI 10 Gigabit Attachment Unit Interface - a standard for connecting 10 Gigabit Ethernet (10GbE) ports to each other and to other electronic devices on a printed circuit board. (X = Roman numeral 10)
XBus A packet-switched bus that supports multiple buses by using a cache controller in large multiprocessing configurations.
XCP XSCF Control Package - XSCF plus OpenBoot PROM
XFP 10Gb Small Form-Factor Pluggable
X-Option An X-option can be ordered after the system is first purchased and installed. The option will be installed in the field. It has a leading "X" (example, X9269A).
XOR eXclusive OR - A binary mathematical operation performed on data to produce parity information. In RAID levels 3 and 5, parity is generated from the user data, stored, and used to regenerate lost data if a drive falure occurs.
XSB eXtended System Board - Any of the logical partitions into which a PSB can be divided.
See also PSB, Uni-XSB, Quad-XSB.
XSCF eXtended System Control Facility - software which includes specific features implemented for OPL
XSCFU eXtended System Control Facility Unit - service processor containing XSCF within an OPL system.
xVM "Intersection of Virtualization and Management" - A family of virtualization products that integrate virtualization and management to help customers manage both physical and virtualized assets across heterogeneous environments.
Y-cable Normally a single connector/plug on one end and 2 connectors/plugs on the opposite end of the cable.
ZIL ZFS Intent Log - ZFS technology which allows addition of SSDs as log devices to improve write performance. Works in conjunction with L2ARC.
Zombie A process that has terminated but remains in the process table because its parent process has not sent the proper exit code. When a user reboots a system, zombie processes are removed from the process table. They consume no system resources.
Zone The administrative boundary within a network domain, often made up of one or more subdomains.
ZFS Sun-created high-capacity file system built on virtual devices to span multiple volumes
(originally Zettabyte File System, but that term is never used anymore)
ZULU Greenwich Mean Time

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