IBM TotalStorage NAS Gateway 500, Service Manual

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machine, the server the supplying machine. 2) This is
not a common term to me. 3) If we do use this term,
shouldn’t it be
client/server model for consistency with
client/server ?
cluster. In high-availability cluster multiprocessing
(HACMP), a set of independent systems (called nodes)
that are organized into a network for the purpose of
sharing resources and communicating with each other.
(1) A station that consists of a control unit (a
cluster
controller ) and the terminals attached to it. (2) A group
of APPN nodes that have the same network ID and the
same topology database. A cluster is a subset of a
network identifier (NETID) subnetwork. (3) Loosely
coupled collection of independent systems organized
into a network for the purpose of sharing resources and
communicating with each other. Can be used to create
highly-available systems. See also
high-availability
cluster multiprocessing (HACMP) and network identifier
(NETID) .
collision avoidance. In carrier sense multiple access
with collision avoidance (CSMA/CA), the process of
sending a jam signal and waiting for a variable time
before transmitting data. The process is designed to
avoid two or more simultaneous transmissions.
Common Internet File System (CIFS). A protocol that
enables collaboration on the Internet by defining a
remote file-access protocol that is compatible with the
way applications already share data on local disks and
network file servers.
communications protocol. In networking, a set of
standards defining how computers are to exchange
information.
connect. In a LAN, to physically join a cable from a
station to an access unit or network connection point.
Contrast with
attach .
control unit. A processor electronics assembly in a
storage controller that exposes logical unit numbers
(LUNs) to the storage network and connects internally
to the storage controller’s disk drives. A storage
controller can have 1 to
n control units, but typically has
one for each path group. See also logical unit number
(LUN) .
CRC. See cyclic redundancy check .
CRU. See customer-replaceable unit .
customer-replaceable unit (CRU). An assembly or
part that a customer can replace in its entirety when any
of its components fail. Contrast with
field-replaceable
unit .
cyclic redundancy check (CRC). (1) A redundancy
check in which the check key is generated by a cyclic
algorithm (T). (2) A system of error checking performed
at both the sending and receiving station after a
block-check character has been accumulated.
D
DASD. See direct access storage device .
data bus. A bus used to communicate data internally
and externally to and from a processing unit, storage,
and peripheral devices (A).
device identifier (ID). An 8-bit identifier that uniquely
identifies a physical I/O device.
device parity protection. A function that protects data
stored on a disk-unit subsystem from being lost
because of the failure of a single-disk unit in the
disk-unit subsystem. When a disk-unit subsystem has
device parity protection and one of the disk units in the
subsystem fails, the subsystem continues to run. The
disk-unit subsystem reconstructs the data after the disk
unit in the subsystem is repaired or replaced. See also
RAID .
DHCP. See Dynamic Host Configuration Protocol .
DIMM. See dual inline memory module .
direct access storage device (DASD). A
mass-storage medium on which a computer stores data.
Contrast with
random access memory (RAM) .
Direct Memory Access (DMA). A technique in which
an adapter bypasses a computer’s CPU, and performs
the transfer of data between itself and the system’s
memory directly.
DMA. See Direct Memory Access .
DNS. See Domain Name System .
Domain Name System (DNS). In the Internet suite of
protocols, the distributed database system used to map
domain names to IP addresses.
drive bay. A receptacle in the NAS Gateway 500 into
which you insert a hard-disk-drive module. The bays are
in storage units that can be located in a different rack
from the the NAS Gateway 500.
dual inline memory module (DIMM). A small circuit
board with memory-integrated circuits containing signal
and power pins on both sides of the board.
Dynamic Host Configuration Protocol (DHCP). A
protocol defined by the Internet Engineering Task Force
(IETF) that is used for dynamically assigning IP
addresses to computers in a network.
E
EIA. See Electronic Industries Association .
EISA. See Extended Industry Standard Architecture .
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NAS Gateway 500 Service Guide