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Open Systems. Computer systems whose standards
are not proprietary.
operating environment. The temperature, relative
humidity rate, and wet bulb temperature of the room in
which the Ultrium Tape Drive routinely conducts
processing.
operating system. The master computer control
program that translates the user’s commands and
allows software application programs to interact with the
computer’s hardware.
optical transceiver. A device that both transmits and
receives analog or digital signals over a light source.
P
parity. The state of being even-numbered or
odd-numbered. A parity bit is a binary number that is
added to a group of binary numbers to make the sum of
that group always odd (odd parity) or even (even parity).
parity error. A transmission error that occurs when the
received data does not have the parity that is expected
by the receiving system. This usually occurs when the
sending and receiving systems have different parity
settings.
port. (1) A system or network access point for data
entry or exit. (2) A connector on a device to which
cables for other devices such as display stations and
printers are attached. (3) The representation of a
physical connection to hardware. A port is sometimes
referred to as an adapter; however, there can be more
than one port on an adapter.
power connector. Located at the rear of the Ultrium
Tape Drive, the connector to which the internal power
cable of an enclosure connects.
power cord. A cable that connects a device to a
source of electrical power.
power-off. To remove electrical power from a device.
power-on, powered-on. (1) To apply electrical power
to a device. (2) The state of a device when power has
been applied to it.
protocol. The meanings of, and the sequencing rules
for, requests and responses that are used to manage a
network, transfer data, and synchronize the states of
network components.
Q
quiesce. To put a device into a temporarily inactive or
inhibited state, but not remove it from the server.
R
read. To acquire or interpret data from a storage
device, from a data medium, or from another source.
reboot. To reinitialize the execution of a program by
repeating the initial program load (IPL) operation.
record. The smallest distinct set of data bytes that is
supplied from a server for processing and recording by
a tape drive, and the smallest distinct set of data to be
read from tape, reprocessed, and made available to a
server by a tape drive.
record boundaries. The fixed limits of a record.
relative humidity. The ratio of the amount of water
vapor actually present in the air to the greatest amount
possible at the same temperature.
repeater. A device that regenerates signals to extend
the range of transmission between data stations or to
interconnect two branches. A repeater is a node of a
local area network.
reset. To return a device or circuit to a clear state.
RS-422 connector. Located at the rear of the Ultrium
Tape Drive, the connector to which the internal RS-422
cable of an enclosure connects. The connection enables
serial devices to communicate with the drive.
RS-422 interface. An electrical interface standard that
is approved by the Electronic Industries Association
(EIA) for connecting serial devices. The RS-422
standard, which supports higher data rates and greater
immunity to electrical interference, is an alternative to
the older RS-232 interface, and uses individual
differential signal pairs for data transmission. Depending
on data transmission rates, RS-422 can be used at
distances up to 1,275 m (4,000 ft). The RS-422
interface also supports multi-point connections.
RS-422 wrap plug. A connector mechanism that
connects to an RS-422 port for the purpose of testing
the Ultrium Tape Drive’s circuitry for the RS-422
interface.
RS-422 wrap test. A diagnostic that can be run on the
Ultrium Tape Drive to determine whether the circuitry
functions properly to and from the RS-422 connector.
S
SAN. See Storage Area Network.
SAN Data Gateway. A device that provides Fibre
Channel attachment between Open Systems servers
and SCSI disk and tape storage systems.
SC. See subscription channel connector.
98 IBM Ultrium Internal Tape Drive
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