Appendix C. Terminology 779
Input/output group
A collection of volumes and canister relationships that present a common interface to host 
systems. Each pair of canister is known as an I/O group.
I/O throttling rate
The maximum rate at which an I/O transaction is accepted for a volume.
iSCSI initiator
An initiator functions as an iSCSI client. An initiator typically serves the same purpose to a 
computer as a SCSI bus adapter would, except that, instead of physically cabling SCSI 
devices (such as hard disk drives and tape changers), an iSCSI initiator sends SCSI 
commands over an IP network. 
iSCSI session
The interaction (conversation) between an iSCSI Initiator and an iSCSI Target. 
iSCSI target
An iSCSI target is a storage resource on an iSCSI server.
Latency
The time interval between the initiation of a send operation by a source task and the 
completion of the matching receive operation by the target task. More generally, latency is the 
time between a task initiating data transfer and the time that transfer is recognized as 
complete at the data destination.
Least recently used
Least recently used (LRU) pertains to an algorithm used to identify and make available the 
cache space that contains the data that was least recently used.
Licensed capacity
The amount of capacity on a storage system that a user is entitled to configure.
License key
An alphanumeric code that activates a licensed function on a product.
License key file
A file that contains one or more licensed keys.
Lightweight Directory Access Protocol
Lightweight Directory Access Protocol (LDAP) is an open protocol that uses TCP/IP to 
provide access to directories that support an X.500 model. It does not incur the resource 
requirements of the more complex X.500 directory access protocol (DAP). For example, 
LDAP can be used to locate people, organizations, and other resources in an internet or 
intranet directory.