NetApp Corporate Glossary

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Numerics

3DES
Data Encryption Standard. A 112-bit algorithm for session encryption.

3DNS
Global server load-balancing solution from F5 Labs that helps distribute traffic across a WAN, based on DNS resolution of client requests. For example, 3DNS identifies which NetCache appliance is nearest a user request and directs the traffic there.

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A

access control list (ACL)
A set of data associated with a file, directory, or other resource that defines users' or groups' access rights to that resource.

Account Migrator Service (AMS)
A service installed on a Windows NT or Windows 2000 system that automatically migrates Windows NT domain users to the filer /etc/passwd file. AMS also has a command-line interface that enables manual control of NT domain user migrations. Developed by NetApp.

ACL
Access Control List. A set of data associated with a file, directory, or other resource that defines users' or groups' access rights to that resource.

active file system
A file system in use, excluding its snapshots.

Active Server Page (ASP)
A Web server scripting language developed by Microsoft for its Internet Information Server.

adapter
An expansion card.

address resolution
The procedure for determining an address corresponding to the address of a LAN or WAN destination.

Address Resolution Protocol (ARP)
A TCP/IP protocol used to obtain a node's physical address.

administration host
A client computer that is used to manage a filer through a Telnet or Remote Shell connection.

administrator
The account that has the required permission to administer a NetApp appliance.

agent
A process that gathers status and diagnostic information and forwards it to network management stations. Also known as "SNMP agent."

American National Standards Institute (ANSI)
A standards organization that defines information technology standards for programming languages, EDI, telecommunications, and physical properties of diskettes, cartridges, and magnetic tapes.

AMS
Account Migrator Service. A service installed on a Windows NT or Windows 2000 system that automatically migrates Windows NT domain users to the filer /etc/passwd file. AMS also has a command-line interface that enables manual control of NT domain user migrations. Developed by NetApp.

ANSI
American National Standards Institute. A standards organization that defines information technology standards for programming languages, EDI, telecommunications, and physical properties of diskettes, cartridges, and magnetic tapes.

API
Application Program Interface. A language and message format used by an application program to communicate with the operating system or some other system, control program, or communications protocol.

appliance
A device that performs a single, well-defined function and is simple to install and operate, for example, a NetCache appliance or NetApp filer.

ApplianceWatch
A suite of products for enterprise system management that is formally certified by leading vendors of system management frameworks. Developed by NetApp.

Application Program Interface (API)
A language and message format used by an application program to communicate with the operating system or some other system, control program, or communications protocol.

application service provider (ASP)
A class of service provider that hosts software applications on its own servers within its own facilities.

application-specific integrated circuit (ASIC)
A custom-designed chip developed for a specific application.

ARP
Address Resolution Protocol. A TCP/IP protocol used to obtain a node's physical address.

ASIC
Application-Specific Integrated Circuit. A custom-designed chip developed for a specific application.

ASP

Active Server Page. A Web server scripting language developed by Microsoft for its Internet Information Server.
Application Service Provider. A class of service provider that hosts software applications on its own servers within its own facilities.
Authorized Service Provider. Third-party organization that services NetApp products.

assertion failure
Type of failure that occurs when a program encounters a line of code that tells the program to panic.

asynchronous transfer mode (ATM)
A network technology that combines the features of cell-switching and multiplexing to offer reliable and efficient network services.

ATM
Asynchronous Transfer Mode. A network technology that combines the features of cell-switching and multiplexing to offer reliable and efficient network services.

authentication
The process of verifying the identity of a user who is logging in to a computer system.

Authorized Service Provider (ASP)
Third-party organization that services NetApp products.

autosupport
Mechanism that triggers e-mail messages from the customer site to NetApp Technical Support or another specified e-mail recipient when a problem occurs with a NetApp appliance.

auto-terminatation
A method by which bus termination is detected and implemented internally such that an external terminator is not required. Currently used on the Fibre Channel StorageShelf FC9.

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B

backup domain controller (BDC)
A copy of the Windows primary domain controller (PDC).

baseline transfer
A complete transfer of a source volume to a mirror volume. The process involves establishing a TCP connection between the mirror and the source and transferring all data blocks from the source volume.

BDC
Backup Domain Controller. A copy of the Windows primary domain controller (PDC).

big-endian
A binary data format for storage and transmission in which the most significant byte comes first.

bind
To establish a software connection between one protocol or application and another, thus creating an internal pathway.

binding ports
A NetApp appliance feature that enables administrators to designate which network interfaces (ports) are configured to handle incoming and outgoing traffic and dedicate them to one direction or the other. This allows, for example, a NetCache appliance to behave like a firewall.

BIOS
Basic Input Output System. The firmware that provides an interface between the operating system and the hardware. See also "open firmware."

blocking factor
In a tape backup operation, the number of tape blocks that are transferred in each write operation.

BSD UNIX
Berkeley Software Distribution UNIX. A version of UNIX developed by the Computer Systems Research Group at the University of California, Berkeley.

BURT
Bug Reporting Tool. The internal system used by NetApp for tracking bugs in NetApp products as well as requests for enhancements or new features. Used also to refer to a report in the BURT system.

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C

cache
Verb. To store data temporarily for expedited access.
Noun. The location in which data is stored temporarily. There are a variety of types of caches, including disk cache, memory cache, and Web cache.

CDDI
Copper Distributed Data Interface. A version of FDDI that uses UTP wires rather than optical fiber.

CDN
Content Delivery Network. A network, or that portion of a network, built specifically to speed the delivery of Web-based content across the public Internet or private intranets.

CFO
Clustered Failover. Method of ensuring data availability by transferring the data service of a failed filer to another filer in the cluster. Transfer of data service is often transparent to users and applications.

chassis
The supporting frame and working parts of a structure. Typically used in reference to a NetApp filer or NetCache appliance.

CIDR
Classless Inter-Domain Routing. A type of network routing that uses the network mask instead of the address class to determine the destination network. NetCache access controls can be specified in CIDR format.

CIFS
Common Internet File System. Microsoft's file-sharing protocol that evolved from SMB.

CIFS authentication mode
The method used for authentication of CIFS users.

CIFS cred
The credential used to validate requests for files with NT-style security.

CIFS share
A directory or directory structure that has been made available to network users and can be mapped to a drive letter on a CIFS client. Also known simply as a "share."

Classless Inter-Domain Routing (CIDR)
A type of network routing that uses the network mask instead of the address class to determine the destination network. NetCache access controls can be specified in CIDR format.

client
A workstation or PC in a client-server architecture; that is, a computer system or process that requests services from and accepts the responses of another computer system or process.

cluster

In Data ONTAP, a pair of filers connected such that one can serve its partner's data if the partner fails.
In NetCache, two or more NetCache appliances that are connected for the purpose of load-balancing of firewall and parenting functions.

clustered failover (CFO)
Method of ensuring data availability by transferring the data service of a failed filer to another filer in the cluster. Transfer of data service is often transparent to users and applications.

cluster interconnect
Cables and adapters with which the two NetApp appliances in a cluster are connected, and over which heartbeat and WAFL log information are transmitted when both appliances are running.

cluster monitor
Software that administers the relationship of filers in a cluster.

Common Internet File System (CIFS)
Microsoft's file-sharing protocol that evolved from SMB.

community
A logical relationship between an SNMP agent and one or more SNMP managers. A community is identified by name, and all members of the community have the same access privileges.

consistency point (CP)
In Data ONTAP, the time at which data is written to disk.

console
A physical or virtual terminal that is used to monitor and control a NetApp appliance.

content provider
Any company in the business of aggregating or producing content for delivery via the Internet.

content delivery network (CDN)
A network, or that portion of a network, built specifically to speed the delivery of Web-based content across the public Internet or private intranets.

controller
An electronic circuit board or system in a computer that allows the computer to use various peripheral devices, for example, a disk controller or Ethernet controller.

cookie
Information sent by a Web server to a client about a particular Web page. This information is generally used to maintain user-specific information and to adjust the appearance of a particular page accordingly, allowing for more personalized content. However, a Web page with a cookie attached to it requires special attention and might be uncacheable.

Copper Distributed Data Interface (CDDI)
A version of FDDI that uses UTP wires rather than optical fiber.

copy-on-write (COW)
The technique for creating snapshots without consuming excess disk space.

core
A short form for "core file." The file that contains the contents of a core dump.

core dump
A display or printout of the contents of memory, usually taken after a system crash.

core file
The file that contains the contents of a core dump.

COW
Copy-On-Write. The technique for creating snapshots without consuming excess disk space.

CP
Consistency Point. In Data ONTAP, the time at which data is written to disk.

CRC
Cyclic Redundancy Check. An error-checking technique that helps ensure accurate transmission of digital data in a network.

CRC error
Cyclic Redundancy Check error. A type of transmission error that may occur due to faulty network hardware, cabling, network interface cards, switch ports, or drivers.

cred
Short for "credential." Access to files and directories is determined by the credentials of the requesting user.

Cricket
A Web-based system that uses SNMP for monitoring trends in time-series data. See also "MRTG."

crossover cable
A cable used to interconnect two computers by reversing, or "crossing over," their respective pin contacts.

CRU
Customer-Replaceable Unit. Any field-replaceable unit (FRU) that can be replaced by the customer.

customer-replaceable unit (CRU)
Any field-replaceable unit (FRU) that can be replaced by the customer.

cyclic redundancy check (CRC)
An error-checking technique that helps ensure accurate transmission of digital data in a network.

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D

DAFS
Direct Access File System. A file system based on virtual interface (VI) architecture, designed for narrow-sharing environments, that is, environments where the machines that are sharing data are only a few yards apart. DAFS bypasses the kernel and transfers data directly from a NIC to a buffer that can be used by an application.

DAR
Direct Access Restore. A process by which select data is restored from an NDMP tape backup device to the filer.

Data ONTAP
A software product designed exclusively for NetApp appliances that optimizes file service by combining patented file-system technology and a microkernel design dedicated to network data access. Developed by NetApp.

DataFabric
A suite of products that allow for the clean separation of the data and the service and application layers by enabling IT staff to create a storage infrastructure that provides a wide range of data accessibility and management services. Developed by NetApp.

DBN
Disk Block Number. A number that identifies a block of data on a disk.

DC
Domain Controller. A computer running NT Server that is contacted when a request comes in to log in a CIFS client or validate a request from an NFS client accessing a file with NTFS-style security. A given domain has one primary domain controller (PDC) and optionally one or more backup domain controllers (BDCs).

degraded mode
The operating mode of a NetApp appliance when a disk in the RAID group has failed or the batteries on the NVRAM card are low.

DES
Data Encryption Standard. A 56-bit algorithm for session encryption.

DFS
Distributed File System. A Windows file management system that allows data scattered across multiple servers to be treated as a single group.

DHCP
Dynamic Host Configuration Protocol. A protocol for automating the assignment of network addresses.

Direct Access File System (DAFS)
A file system based on virtual interface (VI) architecture, designed for narrow-sharing environments, that is, environments where the machines that are sharing data are only a few yards apart. DAFS bypasses the kernel and transfers data directly from a NIC to a buffer that can be used by an application.

direct access restore (DAR)
A process by which select data is restored from an NDMP tape backup device to the filer.

disk block number (DBN)
A number that identifies a block of data on a disk.

disk ID number
A number assigned by the NetApp appliance to each disk when it probes the disks at boot-up, for example, 8.1.

disk scrubbing
The process by which the system reads each disk in a RAID group and attempts to fix media errors by rewriting the data to another disk area. Also known as "RAID disk scrubbing."

disk shelf
A storage unit that contains disk drives.

Distributed File System (DFS)
A Windows file management system that allows data scattered across multiple servers to be treated as a single group.

DNS
Domain Name System. An Internet service for finding computers on an IP network.

DNS caching
A method for preventing unnecessary DNS lookups by caching DNS tables locally.

domain controller (DC)
A computer running NT Server that is contacted when a request comes in to log in a CIFS client or validate a request from an NFS client accessing a file with NTFS-style security. A given domain has one primary domain controller (PDC) and optionally one or more backup domain controllers (BDCs).

Domain Name System (DNS)
An Internet service for finding computers on an IP network.

DOS attributes
Access classifications associated with all DOS files. Typical attributes are read only, archive, hidden, and system.

dump
Noun. A backup to tape, created using the Data ONTAP dump command.

Verb. To make a backup to tape. The data is written in a format that is compatible with the standard BSD-dump format. See also "restore."

dump path
A path that specifies one volume, qtree, or subtree to back up.

Dynamic Host Configuration Protocol (DHCP)
A protocol for automating the assignment of network addresses.

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E

EA
Early Access. Former term for First Customer Shipment (FCS). See "FCS."

Early Access
Former term for First Customer Shipment (FCS). See "FCS."

edge device
Any device, for example a NetCache appliance, that is deployed at the periphery of a LAN and WAN environment to interface traffic from the edge of one network to the other.

EFB
Environmental Fault Bus. A storage shelf component that is used to note disk and shelf events, including disk insertion or removal, fan faults, and power supply faults. Supersedes the EMU.

EMU
Environmental Monitoring Unit. A storage shelf component that is used to note disk and shelf events, including disk insertion or removal, fan faults, and power supply faults.

EMS
Event Management System. A subsystem that controls the generation and propagation of events in the Data ONTAP kernel.

emulated filer
A software copy of the failed filer that is hosted by the takeover filer. The emulated filer appears to users and administrators like a functional version of the failed filer. For example, it has the same name as the failed filer.

end of availability (EOA)
The date when a product ceases to be sold.

end of life (EOL)
The period when a product is supported but not sold.

end of support (EOS)
The period when a product is no longer supported.

environmental fault bus (EFB)
A storage shelf component that is used to note disk and shelf events, including disk insertion or removal, fan faults, and power supply faults. Supersedes the EMU.

environmental monitoring unit (EMU)
A storage shelf component that is used to note disk and shelf events, including disk insertion or removal, fan faults, and power supply faults.

EOA
End Of Availability. The date when a product ceases to be sold.

EOL
End Of Life. The period when a product is supported but not sold.

EOS
End Of Support. The period when a product is no longer supported.

Event Management System (EMS)
A subsystem that controls the generation and propagation of events in the Data ONTAP kernel.

expansion adapter
The hardware used to extend a computer's control over a peripheral device. The expansion adapter includes the expansion card, expansion slot, and connector port.

expansion card
A printed circuit board that plugs into an expansion slot and extends a computer's control over a peripheral device.

expansion slot
The slots on the system board in which you insert expansion cards.

export
The NFS mechanism used to define which areas of the filer are to be made available to NFS clients.

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F

failed filer
The filer in a clustered pair that has ceased operating. It remains the failed filer until giveback succeeds. See also "takeover."

failover
The process by which an alternate system takes over and emulates the primary system if the primary system becomes unusable.

FAServer
The original name for NetApp filers.

fast-narrow (FN)
A type of SCSI bus that supports 8-bit transfer.

fast-wide (FW)
A type of SCSI bus that supports 16-bit transfer.

fast-wide-differential (FWD)
A fast-wide SCSI implementation that uses differential signaling.

FC
Fibre Channel. A high-speed transmission technology.

FC-AL
Fibre Channel-Arbitrated Loop. A type of Fibre Channel network in which devices are connected in a loop topology.

FC-GS
Fiber Channel Generic Services. An ANSI standard that specifies various Fibre Channel services.

FCIA
Fibre Channel Industry Association. A trade association devoted to promoting Fibre Channel technology.

FCS
First Customer Shipment. The initial shipment of a NetApp product. Products with this designation have undergone extensive internal testing and fully met the NetApp criteria for production deployment. See also �GA.�

FDDI
Fiber Distributed Data Interface. An ANSI standard LAN architecture that uses optical fiber cable for high-speed transmission.

FDDI adapter
An adapter for connecting devices to an FDDI network.

FDDI-fiber
An FDDI adapter that supports fiber-optic cable.

FDDI-TP
An FDDI adapter that supports twisted-pair cable.

feeder server
The component of a news server that accepts news feeds from other news servers. It might be on the same computer as other news server software components or it might be on a different computer.

Fibre Channel (FC)
A high-speed transmission technology.

Fibre Channel-Arbitrated Loop (FCAL)
A type of Fibre Channel network in which devices are connected in a loop topology.

Fiber Channel Generic Services (FCGS)
An ANSI standard that specifies various Fibre Channel services.

Fibre Channel Industry Association (FCIA)
A trade association devoted to promoting Fibre Channel technology.

Fiber Distributed Data Interface (FDDI)
An ANSI standard LAN architecture that uses optical fiber cable for high-speed transmission.

field-replaceable unit (FRU)
Any hardware unit that can be replaced at the customer site.

file-level ACL
In a Windows system, a list of permissions associated with a file that determines a user's or group's rights to access the file.

file lock
The implicit state of a file when opened by a client. Depending on the open mode, the file may be locked so as to prevent any other access, or certain types of shared access may be granted.

file mark
Data on a tape that signals the boundaries of a tape file.

file server
A computer that provides file-handing and storage functions for multiple users.

filer
An appliance that attaches to a computer network and is used for data storage. NetApp filers operate using Data ONTAP software.

FilerView
A Web-based tool for administering NetApp filers, which provides access through a graphical user interface. Developed by NetApp.

firewall
A server or device deployed between a LAN and the external WAN to control all inbound and outbound traffic, thus the enhancing security of the network behind the firewall.

First Customer Shipment (FCS)
The initial shipment of a NetApp product. Products with this designation have undergone extensive internal testing and fully met the NetApp criteria for production deployment. See also �GA.�

flush

To clear a memory buffer to by writing the contents of the buffer to disk.
To clear cached data on disk from a NetCache appliance.

FN
Fast-Narrow. A type of SCSI bus that supports 8-bit transfer.

forward proxy
A NetCache appliance configured as an intermediary server that accepts requests from clients and forwards them to a Web server or, if appropriate, services the requests from its own cache. A forward proxy acts as an agent for the client browser. Also known as "Web cache."

FQDN
Fully Qualified Domain Name. The complete name of a specific computer on the Internet, consisting of the computer's host name and its domain name.

FRU
Field-Replaceable Unit. Any hardware unit that can be replaced at the customer site.

fully qualified domain name (FQDN)
The complete name of a specific computer on the Internet, consisting of the computer's host name and its domain name.

FW
Fast-Wide. A type of SCSI bus that supports 16-bit transfer.

FWD
Fast-Wide Differential. A fast-wide SCSI implementation that uses differential signaling.

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G

GA
General Availability. An FCS release that has demonstrated high availability and reliability over a sufficient number of customer sites. This is the release level installed on most new systems.

Gb
Gigabit. One billion bits. Unit of measure for data transfer.

GB
Gigabyte. 1,073,741,824 bytes, or 1,024 megabytes. Unit of measure for computer storage. Sometimes defined as one billion bytes.

GbE
Gigabit Ethernet. A type of high-speed network hardware. Also known as 1000base-T.

General Availability
An FCS release that has demonstrated high availability and reliability over a sufficient number of customer sites. This is the release level installed on most new systems.

GID
Group ID. The number used by UNIX systems to identify groups.

gigabit (Gb)
One billion bits. Unit of measure for data transfer.

gigabyte (GB)
1,073,741,824 bytes, or 1,024 megabytes. Unit of measure for computer storage. Sometimes defined as one billion bytes.

Gigabit Ethernet (GbE)
A type of high-speed network hardware. Also known as 1000base-T.

giveback
The return of identity from the emulated filer to the failed filer, resulting in a return to normal operation. The reverse of takeover.

global group
A collection of user accounts in a Windows NT domain that are members of the domain in which the global group is defined.

group

In Windows NT, a set of user accounts whose individual privileges are determined by the privileges that have been specified for the group.
In Data ONTAP, a group of users defined in the /etc/group file.

group ID (GID)
The number used by UNIX systems to identify groups.

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H

H release
Hardware-specific release. A software product that is restricted to run on an identified platform or subset of platforms. In most cases, an H release is also categorized as an FCS release. Used primarily to enable the timely shipment of new hardware platforms. H releases are identified by the suffix Hx.

HA
High Availability. NetApp support for failover; that is, one appliance assuming the identity and duties of a failed appliance.

halt
To stop, in an orderly manner, all activity in a computer system.

hang
When a computer freezes waiting for an event that will never occur.

HBA
Host Bus Adapter. Any hardware bridge between a storage interconnect and a system's I/O bus.

head
The filer chassis that contains the motherboard.

heartbeat
A repeating signal transmitted from one appliance to another that indicates that the appliance is in operation. Heartbeat information is also stored on disk.

high availability (HA)
NetApp support for failover; that is, one appliance assuming the identity and duties of a failed appliance.

host bus adapter (HBA)
Any hardware bridge between a storage interconnect and a system's I/O bus.

hot spare
A disk in a NetApp appliance that can be used to substitute for a failed disk. Before the disk failure, the hot spare disk is not part of a RAID group.

hot swap
To add, remove, or replace a disk in a NetApp appliance while the appliance is running.

HTTPS
Hypertext Transport Protocol Secure. A variant of HTTP used for accessing secure Web servers. See also "SSL."

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I

iCAP
Internet Content Adaptation Protocol. A high-level protocol that provides a common format for requesting services from a server.

ICP
Internet Cache Protocol. The method by which a hierarchy of NetCache appliances communicate with each other. ICP, which runs on top of UDP, enables NetCache to query other caches for individual Web pages.

IIS
Internet Information Server. Web server software developed by Microsoft.

If-Modified-Since (IMS)
A query that NetCache sends to a Web server in order to verify the freshness of an object, that is, to determine whether the object has been modified.

IMS
If-Modified-Since. A query that NetCache sends to a Web server in order to verify the freshness of an object, that is, to determine whether the object has been modified.

increment chain
A series of incremental backups of the same path.

Internet Cache Protocol (ICP)
The method by which a hierarchy of NetCache appliances communicate with each other. ICP, which runs on top of UDP, enables NetCache to query other caches for individual Web pages.

Internet Content Adaptation Protocol (iCAP)
A high-level protocol that provides a common format for requesting services from a server.

Internet Information Server (IIS)
Web server software developed by Microsoft.

interrupt switch
A switch on the front panels of some NetApp appliances that is used for debugging purposes.

IP address
The unique numerical address of a computer that is attached to a TCP/IP network, for example, 198.95.226.66.

IPL
Initial Program Load. The initial execution of instructions on a computer when it is powered on or reset. Also known as "boot."

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J

JBOD
Just a Bunch Of Disks. An array of disks without any redundancy, that is, without RAID configuration.

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K

Kb
Kilobit. One thousand bits. Unit of measure for data transfer.

KB
Kilobyte. 1,024 bytes. Unit of measure for computer storage.

Kbps
Kilobits per second. A digital transmission speed.

keepalive
A network option that detects inactivity on a client-server connection and, if detected, terminates the connection.

kilobit (Kb)
One thousand bits. Unit of measure for data transfer.

kilobyte (KB)
1,024 bytes. Unit of measure for computer storage.

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L

LANE
LAN Emulation. The architecture, protocols, and services that allow ATM-connected end systems to use the ATM network as if it were a LAN.

LDAP
Lightweight Directory Access Protocol. A client-server protocol for accessing a directory service. NetCache can be configured to point to an LDAP server for authentication of user requests; later versions of Data ONTAP can use Microsoft�s Active Directory, which uses LDAP.

LFS
Log-structured File System. A file system that avoids both multiple-write and synchronous-write problems by batching large numbers of writes into large, contiguous writes.

Lightweight Directory Access Protocol (LDAP)
A client-server protocol for accessing a directory service. NetCache can be configured to point to an LDAP server for authentication of user requests; later versions of Data ONTAP can use Microsoft�s Active Directory, which uses LDAP.

little-endian
A binary data format for storage and transmission in which the least significant byte comes first.

live stream
A streaming media presentation that occurs in real time.

load balancer
A type of networking switch that is able to utilize additional information beyond a simple destination MAC/IP address to distribute, or load balance, incoming requests across servers or caches according to various algorithms.

local filer
The filer you are logged in to.

local group
A collection of user accounts and global groups in a Windows NT domain. Unlike global groups, local groups can contain members from other, trusted domains.

Logical Unit Number (LUN)
A logical unit of storage.

log-structured file system (LFS)
A file system that avoids both multiple-write and synchronous-write problems by batching large numbers of writes into large, contiguous writes.

LUN
Logical Unit Number. A logical unit of storage.

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M

mailbox disk
One of a set of disks owned by each filer that is used to store the cluster state information of the filer.

maintenance mode
One of the options available when you boot a NetApp appliance from a system boot disk. Maintenance mode provides special commands for troubleshooting hardware and system configuration.

Management Information Base (MIB)
ASCII files that describe the information that the SNMP agent sends to network management stations.

Mb
Megabit. One million bits. Unit of measure for data transfer.

MB
Megabyte. 1,048,576 bytes, or 1,024 KB. Unit of measure for computer storage.

Mbps
Megabits per second. A digital transmission speed.

MD5
Message Digest 5. An algorithm for checksum generation for use in security applications. See also "RSA."

mean time between failures (MTBF)
A measure of the mean time a component works before failing.

mean time to repair (MTTR)
A measure of the mean time required to repair a failed component.

megabit (Mb)
One million bits. Unit of measure for data transfer.

megabyte (MB)
1,048,576 bytes, or 1,024 KB. Unit of measure for computer storage.

Message Digest 5 (MD5)
An algorithm for checksum generation for use in security applications. See also "RSA."

MIB
Management Information Base. ASCII files that describe the information that the SNMP agent sends to network management stations.

Microsoft Management Console (MMC)
A GUI framework for management applications.

Microsoft Media Streaming (MMS)
The streaming media control protocol used in Windows Media Technologies 3 and 4 streams.

MIME
Multipurpose Internet Mail Extensions. A specification that defines the mechanisms for specifying and describing the format of Internet message bodies. An HTTP response containing the MIME Content-Type header allows the HTTP client to invoke the application that is appropriate for the data received.

mirror
A volume that contains a read-only copy of data in the active file system of another volume, usually on another filer.

MMC
Microsoft Management Console. A GUI framework for management applications.

MMS
Microsoft Media Streaming. The streaming media control protocol used in Windows Media Technologies 3 and 4 streams.

mount
To make the file system on a particular device accessible by attaching it to the file hierarchy.

MRTG
Multi-Router Traffic Grapher. A Web-based tool for monitoring traffic and other SNMP variables on network connections. See also "Cricket."

MTBF
Mean Time Between Failures. A measure of the mean time a component works before failing.

MTTR
Mean Time To Repair. A measure of the mean time required to repair a failed component.

Multi-Router Traffic Grapher (MRTG)
A Web-based tool for monitoring traffic and other SNMP variables on network connections. See also "Cricket."

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N

name server
A network server that provides a directory service. See also "DNS," "NIS," and "WINS."

NAP
Network Access Point. Traditionally the point at which an entity connects to the public Internet; but the term generically applies to any point of entry to a WAN.

NAS
Network Attached Storage. A file-storage device that is accessed through a network.

NDMP
Network Data Management Protocol. A communications protocol for backing up data in a heterogeneous environment.

NetApp
The trademarked short form for NetApp, Inc.

NetCache
The proprietary software that runs on NetCache appliances. Developed by NetApp.

NetCache appliance
An appliance designed specifically to serve Internet and intranet content quickly and reliably. Developed by NetApp.

NetCache Manager
The browser interface through which a NetCache appliance is managed.

network access point (NAP)
Traditionally the point at which an entity connects to the public Internet; but the term generically applies to any point of entry to a WAN.

network adapter
A printed circuit board that connects a computer or other node to a network. Also known as a "network interface card" or "NIC."

network attached storage (NAS)
A file-storage device that is accessed through a network.

Network Data Management Protocol (NDMP)
A communications protocol for backing up data in a heterogeneous environment.

Network File System (NFS)
A client-server protocol for sharing files and directories over a network.

Network Information Service (NIS)
An administrative database for networks. Formerly called Yellow Pages.

network interface card (NIC)
A printed circuit board that connects a computer or other node to a network. Also known as a "network adapter."

network lock manager
A facility that works with NFS to provide a System V-style of advisory file and record locking over the network.

network management station (NMS)
A client workstation on a network that uses a third-party application (SNMP) to process status and diagnostic information.

network trace
A facility for tracing the route of a computer that is connected to the Internet. See also "packet trace."

news cache
A NetCache appliance configured to accept news requests from clients and to fetch requested news data from a news server or another NetCache appliance that connects to a news server.

NFS
Network File System. A client-server protocol for sharing files and directories over a network.

NIC
Network interface card. A printed circuit board that connects a computer or other node to a network. Also known as a "network adapter."

NIS
Network Information Service. An administrative database for networks. Formerly called Yellow Pages.

NMS
Network Management Station. A client workstation on a network that uses a third-party application (SNMP) to process status and diagnostic information.

nonvolatile random access memory (NVRAM)
Type of computer memory that retains data in the event of a loss of power. In NetApp filers, NVRAM is used for logging incoming write data and requests.

normal mode
The state of a filer when there is no takeover in the cluster.

NOW
NetApp On the Web. The secure customer service Web site for NetApp.

NTAP
The NetApp stock-ticker symbol on NASDAQ.

NT domain
A group of Windows NT systems that share a common database of security objects. A filer must be installed into a domain in order to use NTFS-style security.

NTP
Network Time Protocol. A protocol used to synchronize computer clocks in a network.

NT file system (NTFS)
The Windows NT hierarchical file system.

NTFS
NT File System. The Windows NT hierarchical file system.

NTFS permissions
The permissions used in NTFS-style security to control access to files and directories.

NT LAN Manager (NTLM)
A Windows NT authentication protocol; supported by NetCache.

NTLM
NT LAN Manager. A Windows NT authentication protocol; supported by NetCache.

NTLM credential
A message containing a challenge and response, sent from the browser to NetCache or from NetCache to a domain controller, for the purpose of authenticating a user.

NVFAIL
Software that warns you of compromised database validity and automatically renames the database so that it does not restart automatically. Developed by NetApp.

NVRAM
Nonvolatile Random Access Memory. Type of computer memory that retains data in the event of a loss of power. In NetApp filers, NVRAM is used for logging incoming write data and requests.

NVRAM mirror
A synchronously updated copy of the contents of a clustered filer's NVRAM stored on the partner filer.

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O

OFW
Open Firmware. The firmware or system startup code used in some NetApp appliances. Like the widely known BIOS, OFW is used to bring the hardware out of reset and perform basic configuration of the system before transferring control to Data ONTAP.

on-demand stream
A previously recorded media stream that users can request at a time most convenient to them. Users can rewind and fast-forward on-demand media streams. Also known as "video on demand" or "VOD."

ONTAP
Open Network Technology for Appliance Products. Generally referred to as Data ONTAP.

open firmware (OFW)
The firmware or system startup code used in some NetApp appliances. Like the widely known BIOS, OFW is used to bring the hardware out of reset and perform basic configuration of the system before transferring control to Data ONTAP.

Open Systems Interconnect (OSI)
A standard description for transmitting data in a telecommunications network. OSI defines a framework for implementing protocols in seven layers: physical (1), data link (2), network (3), transport (4), session (5), presentation (6), and application (7).

OSI
Open Systems Interconnect. A standard description for transmitting data in a telecommunications network. OSI defines a framework for implementing protocols in seven layers: physical (1), data link (2), network (3), transport (4), session (5), presentation (6), and application (7).

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P

packet trace
A facility for tracing network traffic that is directed to a filer. See also "network trace."

panic
A serious error condition that causes the NetApp appliance to stop operating. Similar to a software crash in the Windows system environment.

parity checking
A method of data verification. Parity information is used to reconstruct data.

parity disk
Disk on which parity information is stored for a RAID group.

partner
A member of a clustered pair. From the point of view of the local filer, the other filer in the cluster is the partner. See also "takeover partner."

partner mode
The method used to communicate through the command-line interface with the failed filer in a cluster during a takeover.

PCB carrier
Printed Circuit Board carrier. The unit that slides out from the chassis of a NetApp appliance and might contain (depending on the PCB carrier) expansion adapters, DIMMs, and motherboard.

PCI
Peripheral Component Interconnect. A bus architecture.

(PC)NFS
Personal Computer Network File System.

PDC
Primary Domain Controller. In Windows, the computer that manages security for its local domain.

permanent virtual circuit (PVC)
A network connection with a static route defined in advance, usually by manual setup.

permissions
In UNIX, the bits that determine access to files. See also "ACL" and "privileges."

persistent connection
A connection between two networked devices that remains opened after the initial request is complete, to handle additional requests.

Point of Presence (POP)
A remote location that provides network connectivity back to the core of the network for users within its service area. Service providers deploy POPs to give customers an entry point to their networks from their local loops.

POP
Point of Presence. A remote location that provides network connectivity back to the core of the network for users within its service area. Service providers deploy POPs to give customers an entry point to their networks from their local loops.

POST
Power-On Self-Tests. A series of diagnostic tests performed by a computer when it is turned on.

power-on self-tests (POST)
A series of diagnostic tests performed by a computer when it is turned on.

power supply unit (PSU)
The replaceable device that supplies power to a NetApp appliance.

prefetch
The process of retrieving and caching data before it is requested by the client.

privileges
In Windows, the rights associated with SIDs to perform certain operations. See also "ACL" and "permissions."

proxy mode
The default mode of operation for NetCache in which the cache serves all users who set up their browsers to use NetCache as their proxy. While acting as a proxy, NetCache also caches Web pages requested by users, greatly decreasing response time for subsequent requests for the same Web page, as well as greatly decreasing total network bandwidth usage. See also "forward proxy" and "reverse proxy."

proxy server
A server, deployed between users and a network or servers, that intercepts and terminates user requests. These requests are then forwarded, or "proxied," to the network on behalf of the user.

PSU
Power supply unit. The replaceable device that supplies power to a NetApp appliance.

PVC
Permanent virtual circuit. A network connection with a static route defined in advance, usually by manual setup.

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Q

Quality of Service (QoS)
The performance level defined for a data communications system.

QoS
Quality of Service. The performance level defined for a data communications system.

qtree
A special subdirectory in a volume that acts as a virtual subvolume with special attributes, primarily quotas and permissions.

quota
A limit that restricts disk space usage.

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R

RADIUS
Remote Authentication Dial-In User Service. A client-server protocol for accessing a directory service. NetCache can be configured to point to a RADIUS server for authentication of user requests.

RAID
Redundant Array of Independent Disks. NetApp appliances use RAID 4, which protects against disk failure by computing parity information based on the contents of all the disks in the array.

RAID group
A set of data disks and a parity disk that implement RAID 4.

RAID disk scrubbing
The process by which the system reads each disk in the RAID group and tries to fix media errors by rewriting the data to another disk area. Also known simply as "disk scrubbing."

RARP
Reverse Address Resolution Protocol. A way of converting Ethernet addresses to IP addresses.

reader server
The component of a news server that obtains the data that the news cache requests from the news storage device. If the news cache does not have that requested news, it connects to the reader server component of the news server, through NNTP.

Real Time Streaming Protocol (RTSP)
An open standard for delivery of real-time media over the Internet.

Real-time Transport Control Protocol (RTCP)
A feedback protocol that provides QoS information to the streaming server. The RTCP feedback mechanism periodically describes the state of the network so the streaming server and client can negotiate the optimum bit rate for current network conditions. By default, RTCP uses UDP for transport.

Real-time Transport Protocol (RTP)
An Internet protocol for the transmission of real-time data, including voice and video.

Recommended Release (RR)
Former term for General Availability (GA). See "GA."

redundant array of independent disks (RAID)
NetApp appliances use RAID 4, which protects against disk failure by computing parity information based on the contents of all the disks in the array.

Remote Authentication Dial-In User Service (RADIUS)
A client-server protocol for accessing a directory service. NetCache can be configured to point to a RADIUS server for authentication of user requests.

Remote Shell
A program that enables a user on one system to execute a program on another system. Remote Shells are usually established with the rsh command and are not interactive.

request for enhancement (RFE)
Request for change or enhancement to an existing system or application.

restore
To copy back to the filer data files that were backed up to tape using the Data ONTAP dump command. See also "dump."

return material authorization (RMA)
Paperwork for returning a product to the manufacturer.

Reverse Address Resolution Protocol (RARP)
A way of converting Ethernet addresses to IP addresses.

reverse proxy
A specific deployment of a proxy server as a front-end accelerator between the origin servers and the incoming user connections. Also known as "Web acceleration."

RFE
Request For Enhancement. Request for change or enhancement to an existing system or application.

RMA
Return Material Authorization. Paperwork for returning a product to the manufacturer.

root volume
The volume that a NetApp appliance first looks at when booting to obtain configuration information.

RR
Recommended Release. Former term for General Availability (GA). See "GA."

RSA
Rivest, Shamir, and Adleman. Public key encryption algorithm.

rsh
The command used to establish a Remote Shell connection.

RTCP
Real-time Transport Control Protocol. A feedback protocol that provides QoS information to the streaming server. The RTCP feedback mechanism periodically describes the state of the network so the streaming server and client can negotiate the optimum bit rate for current network conditions. By default, RTCP uses UDP for transport.

RTP
Real-time Transport Protocol. An Internet protocol for the transmission of real-time data, including voice and video.

RTSP
Real Time Streaming Protocol. An open standard for delivery of real-time media over the Internet.

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S

SAN
Storage Area Network. A network that transfers data between computer systems and storage devices via peripheral channels such as SCSI or Fibre Channel.

SCSI
Small Computer System Interface. The hardware interface between the computer and peripheral devices, such as storage systems.

SCSI address
The full address of a device, consisting of the SCSI adapter number and SCSI ID, for example, 8a.1

SCSI ID
The number of a device on the SCSI chain.

SD
Security Descriptor. The NTFS security information associated with a file. The SD contains the owner SID; owning group SID, which is not used; the Discretionary ACL, which is used to control access to files; and the System ACL, which is used to control auditing of file accesses.

SecureAdmin
A security product that enables you to administer a NetApp appliance in a nontrusted environment by creating a secure exchange between a client and the NetApp appliance using SSH and SSL protocols. Developed by NetApp.

SecureShare
A suite of products that enable UNIX and Windows-based applications to concurrently access and update shared files, with the integrity and cache coherency of the shared data being protected by enforced locking and file-open semantics. SecureShare coordinates and manages all lock types used with multiprotocol file sharing. Developed by NetApp.

Secure Shell (SSH)
A protocol that is a standard method for replacing Telnet and Remote Shell sessions to secure encrypted communication over the Internet.

Secure Sockets Layer (SSL)
A protocol that is a standard method for secure, encrypted communication over the Internet. See also "HTTPS."

security descriptor (SD)
The NTFS security information associated with a file. The SD contains the owner SID; owning group SID, which is not used; the Discretionary ACL, which is used to control access to files; and the System ACL, which is used to control auditing of file accesses.

security ID (SID)
The unique identifier that is used to identify Windows NT security objects (users and groups).

security style
The security scheme in effect for a given file or directory. This may be UNIX-style, NTFS-style, or mixed. Any given file or directory has only one effective style at a given time. File accesses with UNIX-style security are validated using the UNIX security mechanisms; files with NTFS-style security are validated using the NTFS security mechanisms.

serial console
A terminal attached to the serial port of a NetApp appliance. Used to monitor and manage the appliance's operations.

server
A computer that provides services for other computers connected to it in a network.

Server Message Block (SMB)
The Microsoft file-sharing protocol that preceded CIFS.

SFS
System-level File Server. A series of SPEC benchmarks for NFS performance.

share
A directory or directory structure that has been made available to network users and can be mapped to a drive letter on a CIFS client. Also known as a "CIFS share."

share-level ACL
In Windows, a special type of ACL, distinct from ACLs on files, that can be used to restrict access to various users or groups.

shut down
To halt and power off a computer.

SID
Security ID. The unique identifier that is used to identify Windows NT security objects (users and groups).

Simple Network Management Protocol (SNMP)
A standard Internet protocol that facilitates communications between a system being managed and the management console or framework.

SmartFilter
Software that restricts access to Web sites. It identifies the sites that contain content in various categories, maintains lists of those sites in control files, and restricts access accordingly.

SMB
Server Message Block. The Microsoft file-sharing protocol that preceded CIFS.

SnapCopy
A software feature that enables you to copy one volume to another through the vol copy command set. Developed by NetApp.

SnapManager for Exchange
A suite of products that provide rapid data recovery for Microsoft Exchange, back up files without interrupting e-mail service, and enable efficient management of Information Stores. Developed by NetApp.

SnapMirror
A product that performs automated file system replication of a volume onto the same or a separate disk or filer. Developed by NetApp.

SnapRestore
A product that restores an entire volume to the state recorded in a previously taken snapshot. Developed by NetApp.

Snapshot
A Data ONTAP feature that creates an online, read-only copy of the entire file system--called a "snapshot"--that protects against accidental deletions or modifications of files without duplicating file contents.

Snapshot reserve
The portion of a volume's disk space that is reserved for snapshots.

SNIA
Storage Networking Industry Association. An organization dedicated to the advancement and development of standards for network storage.

SNMP
Simple Network Management Protocol. A standard Internet protocol that facilitates communications between a system being managed and the management console or framework.

SNMP agent
A process that gathers status and diagnostic information and forwards it to network management stations.

SNMP community
Name that is used as a password by the SNMP manager to communicate with the SNMP agent.

SNMP trap
An asynchronous, unsolicited message sent by an SNMP agent to an SNMP manager indicating that an event has occurred on the filer. Also known simply as a "trap."

SNTP
Simple Network Time Protocol. A variation of NTP used to synchronize computer clocks on the Internet.

soft link
A file system object that can be used to redirect a path transparently to another part of the file system. Also known as "symlink" or "symbolic link."

SPEC
Standard Performance Evaluation Company. An organization that establishes computer performance benchmarks.

SSH
Secure Shell. A protocol that is a standard method for replacing Telnet and Remote Shell sessions to secure encrypted communication over the Internet.

SSL
Secure Sockets Layer. A protocol that is a standard method for secure, encrypted communication over the Internet. See also "HTTPS."

storage area network (SAN)
A network that transfers data between computer systems and storage devices via peripheral channels such as SCSI or Fibre Channel.

Storage Networking Industry Association (SNIA)
An organization dedicated to the advancement and development of standards for network storage.

stream
A media file that is transmitted in a continuous flow over a network. Streams are of two types, live and on-demand.

stream splitting
The process of delivering a unique stream to multiple clients simultaneously. Stream splitting reduces the number of requests sent across the network to the streaming server.

streaming accelerator
A NetCache appliance configured to cache and split content from one or more streaming servers and provide that content to clients that request it.

streaming media
A term used to describe media files that begin playing while they are being transmitted over the network to the media player on the client computer.

streaming media cache
A NetCache appliance configured to proxy client requests for streaming media. Also known as "streaming media proxy."

streaming media presentation
A general term used to describe the delivery of live or on-demand streaming media. A streaming media presentation can consist of multiple unique streams.

streaming server
A server configured to serve streaming media to clients.

SVC
Switched Virtual Circuit. An ATM network connection established through signaling. The user defines the endpoints when the call is initiated.

switched virtual circuit (SVC)
An ATM network connection established through signaling. The user defines the endpoints when the call is initiated.

symbolic link
A file system object that can be used to redirect a path transparently to another part of the file system. Also known as "symlink" or "soft link."

symlink
A file system object that can be used to redirect a path transparently to another part of the file system. Also known as "symbolic link" or "soft link."

system board
A printed circuit board that contains the CPU, expansion bus slots, and system memory. Also known as a "motherboard."

system-level file server (SFS)
A series of SPEC benchmarks for NFS performance.

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T

takeover

In Data ONTAP, the emulation of the failed filer identity by the takeover filer in a cluster; the reverse of giveback.
In NetCache, the configuration of one specific NetCache appliance to take over NetCache servicing functions of one other NetCache appliance in the event of failure.

takeover filer
A filer that remains in operation after the other filer in a cluster stops working and that hosts an emulated filer that manages access to the failed filer disk shelves and network connections. The takeover filer maintains its own identity and the emulated filer maintains the failed filer identity.

takeover mode
A management mode used from a takeover filer to interact with a failed filer. The console prompt indicates when the filer is in takeover mode.

takeover partner
The NetCache appliance that is configured to take over certain specified functions of a partner appliance if that partner appliance fails.

tape block
A unit of data on tape.

tape device
A logical representation in the file system of a piece of tape hardware, such as a tape device or stacker.

tape file
Data on a tape delimited by file marks.

tape library
Hardware that can access tape cartridges randomly.

tape media changer
Hardware that can load and unload tape cartridges.

tape stacker
Hardware that can access tape cartridges from a stack.

TB
Terabyte. 1,024 GB. Unit of measure for computer storage.

Terabyte (TB)
1,024 GB. Unit of measure for computer storage.

thinning
In streaming media, the streaming server's process of dropping a consistent number of video or audio frames to try to ensure the data being delivered to the client is streamed more efficiently during playback.

Time To Live (TTL)
The time limit on how long a copy of an object remains in the cache before NetCache verifies the object with the originating Web server.

TP
Twisted Pair. A type of wire generally used for telephone and network cabling.

traceroute
A utility that records the route of a computer connected to the Internet.

transparency
A network configuration in which client Internet requests are automatically routed through a NetCache appliance without any user knowledge or special browser configuration required.

trap
An asynchronous, unsolicited message sent by an SNMP agent to an SNMP manager indicating that an event has occurred on the filer. Also known as "SNMP trap."

tree quota
A type of disk quota that restricts the disk usage of a qtree.

TSE
Technical Support Engineer.

TTL
Time To Live. The time limit on how long a copy of an object remains in the cache before NetCache verifies the object with the originating Web server.

twisted pair (TP)
A type of wire generally used for telephone and network cabling.

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U

U
Unit. A standard vertical measurement of rack space.

UDP
User Datagram Protocol. A connectionless network protocol that provides simple but unreliable transmission. An alternative to TCP that does not contain error checking.

UID
User ID. Any numerical identifier for users in a computer system.

Unicode
A 16-bit character set standard. It was designed and is maintained by the nonprofit consortium Unicode, Inc. (http://www.unicode.org/).

uninterruptible power supply (UPS)
Backup power supply that is available when the electrical power fails or drops to unacceptable levels.

unique stream
A stream whose connection speed, media type, or thinning parameters are different from another stream that is part of the same streaming media presentation.

UNIX cred
The credential used to validate requests when accessing files with UNIX-style security. It consists of the UID and a list of GIDs corresponding to the groups to which the user belongs. In the case of NFS requests, the UNIX cred is passed with each request. For CIFS clients, the UNIX cred is constructed at login from the mapped UNIX identity.

UNIX permissions
The bits used in UNIX-style security to control access to files and directories. These include the owning UID, the owning GID, and separate read, write, and execute permissions for each of three categories of users: the owner, group members, and everyone else.

unmount
To make the file system on a particular device inaccessible by detaching it from the file hierarchy.

unshielded twisted pair (UTP)
A type of wire generally used for telephone and network cabling.

UPS
Uninterruptible Power Supply. Backup power supply that is available when the electrical power fails or drops to unacceptable levels.

User Datagram Protocol (UDP)
A connectionless network protocol that provides simple but unreliable transmission. An alternative to TCP that does not contain error checking.

user ID (UID)
Any numerical identifier for users in a computer system.

user mapping
A method of assigning identities between UNIX and NTFS, where one identity is mapped to another.

UTF
Universal Transformation Format. A method for conversion of 16-bit Unicode characters into 7-bit or 8-bit characters.

UTP
Unshielded twisted pair. A type of wire generally used for telephone and network cabling.

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V

VCI
Virtual Channel Identifier. A unique numerical tag defined by a 16-bit field in the ATM cell header that identifies a virtual channel over which the cell is to travel.

VI
Virtual Interface. An architecture designed to allow bulk data transfer directly to or from application buffers. VI also allows applications to access VI-capable hardware directly without operating system intervention. See also "VIF."

video on demand (VOD)
A previously recorded media stream that users can request at a time most convenient to them. Users can rewind and fast-forward on-demand media streams. Also known as "on-demand stream."

VIF
A single virtual interface that is created from multiple physical interfaces by using the EtherChannel technology. Created using the Data ONTAP vif command.

virtual channel identifier (VCI)
A unique numerical tag defined by a 16-bit field in the ATM cell header that identifies a virtual channel over which the cell is to travel.

virtual interface (VI)
An architecture designed to allow bulk data transfer directly to or from application buffers. VI also allows applications to access VI-capable hardware directly without operating system intervention. See also "VIF."

virtual local area network (VLAN)
A LAN created via software rather than dedicated hardware.

virtual path identifier (VPI)
A field in the ATM cell header that indicates the virtual path over which the cell should be routed.

VLAN
Virtual local area network. A LAN created via software rather than dedicated hardware.

VOD
Video On Demand. A previously recorded media stream that users can request at a time most convenient to them. Users can rewind and fast-forward on-demand media streams. Also known as "on-demand stream."

volume
An independent file system with its own RAID groups.

volume copy
A way of copying both data in the active file system and data in snapshots from one volume to another. Implemented using the volcopy command.

VPI
Virtual path identifier. A field in the ATM cell header that indicates the virtual path over which the cell should be routed.

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W

WAFL
Write Anywhere File Layout. A patented file system designed exclusively for NetApp appliances to optimize write performance. Developed by NetApp.

WAFL check
Data ONTAP utility to repair filer volumes.

WAFL credential cache (WCC)
A temporary in-memory database that keeps mappings from UNIX UIDs to CIFS credentials.

WCC
WAFL credential cache. A temporary in-memory database that keeps mappings from UNIX UIDs to CIFS credentials.

WCCP
An open protocol that when installed on Cisco Routers enables them to transparently redirect client browser Web requests from their target Web servers to a Web cache.

Web acceleration
A specific deployment of a proxy server as a front-end accelerator between the origin servers and the incoming user connections. Also known as "reverse proxy."

Web accelerator
A NetCache appliance configured as an intermediary server that caches content from one or more servers and provides that content to clients that request it.

Web cache
A NetCache appliance configured as an intermediary server that accepts requests from clients and forwards them to a Web server or, if appropriate, services the requests from its own cache. A Web cache acts as an agent for the client browser. Also known as "forward proxy."

Web Cache Communication Protocol (WCCP)
An open protocol that when installed on Cisco Routers enables them to transparently redirect client browser Web requests from their target Web servers to a Web cache.

widelink
A parameter that controls whether or not links in the UNIX file system may be followed by the server. Links that point to areas within the directory tree exported by the server are always allowed; this parameter controls access only to areas that are outside the directory tree being exported.

Windows Internet Naming Service (WINS)
Microsoft name service.

Windows Media Technologies (WMT)
A collective term for Microsoft's streaming audio and video technologies.

WINS
Windows Internet Naming Service. Microsoft name service.

WMT
Windows Media Technologies. A collective term for Microsoft's streaming audio and video technologies.

workgroup
A collection of computers running Windows NT or Windows for Workgroups that is grouped for browsing and sharing.

Write Anywhere File Layout (WAFL)
A patented file system designed exclusively for NetApp appliances to optimize write performance. Developed by NetApp.

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X

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Y

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Z

zero
Verb. To replace all blocks on a disk with zeros.