Sun Oracle Storage Tek T10000, Reference Manual

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Glossary
258 T10000: Interface Reference Manual • January 2011 • E20425-01
select another port to send data to or receive
data from that same port.
Arbitrated Loop A topology in Fibre Channel
that provides multiple connections for devices
that share a single loop, over which only two
devices can communicate at once. Similar to the
SCSI protocol of the same name, it provides an
“arbitrate and win” scenario between more than
two devices when those devices want to
communicate on the bus. The sending device
must arbitrate and win the connection with the
receiving device before communication can
begin.
Arbitrated Loop Physical Address A one-byte
value that identifies a port in an arbitrated loop
topology.
arbitration Any process by which a user of a
shared resource negotiates with other users for
the right to use the resource. A port connected to
a shared bus must win arbitration before it
transmits data on the bus
Asynchronous Event Notification A form of
communication used between processes to
notify a process of an asynchronous action, such
as an input/output activity or message
transmission.
B
b The abbreviation for bit.
B The abbreviation for byte.
BB_Credit See buffer-to-buffer credit.
Buffer Size The amount of storage space
allocated to the buffer, which is a storage space
reserved temporarily for a given purpose. In
Fibre Channel, this buffer is usually larger than a
single frame, up to the size of an entire
sequence.
Buffer-to-Buffer Credit This is a value which is
managed by the R_RDY primitive signal on a
link, and is used by a transmitter to determine the
permission to transmit frames. If permission is
granted by the recipient, this value also tells the
transmitter how many are permitted. The
transmitter may transmit a frame when Available
BB_Credit is greater than 0. This differs from
End_to_End Credit.
Buffer-to-Buffer A method of transferring
information in which neither the initiator nor
receiver of the information knows the contents.
Byte A group of eight bits.
C
CDB Command descriptor block. A structure for
SCSI commands.
Channel An I/O interface between a central
processor and peripheral device in which large
amounts of data are transferred at the highest
rate of speed possible for the transmission
medium.
Class of Service The Fibre Channel method of
defining a data transmission strategy between
devices. There are three FC Classes of Service
currently specified in the FC-PH-1, and
StorageTek’s implementation includes only one,
Class 3.
Class 3 The Fibre Channel Class of Service in
which the initiator sends a message to a
receiving device without expecting or requiring
an acknowledgement. It is analogous to the
human communication method of sending an
advertisement in hopes that the message is
received.
CLS Close.
Company ID A unique address in IEEE
proposed format.
Control Byte The last byte of every Command
Descriptor Block. The Control Byte contains two
vendor-specific bits, four reserved bits, one flag
bit, and one link bit.
CRC See Cyclic Redundancy Check
Cyclic Redundancy Check A mechanism used
for error detection that calculates a numeric
value by using a special algorithm applied to a
series of bytes that are generally appended to
the data. If no error has occurred when the
receiver executes the algorithm on the received
data, the newly generated CRC value should be
the same as the CRC value originally
transmitted.