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Hub
A switching device through which a
number of devices (such as
computers) can be connected to a
network. Since connected devices are
arrayed with the hub at the center,
this type of connection is referred to
as a star topology. Most hubs used
with the Internet are equipped with
signal amplifier (repeater) to support
physical extensions.
IP address
An identifier used to indicate the
addresses of devices (such as
computers) that are connected to a
network. Since this identifier is used
to designate a particular destination
during data exchange, each IP
address must be unique. The address
consists of four period-delimited
fields, each consisting of a number
from 0 to 255. (In other words, a
group of four 8-bit decimal numbers,
where a bit is the smallest unit of data
handled by a computer, and
represents a 1-digit binary number of
0 or 1. With 8 bits, 28 or 256 values
can be represented; e.g.,
123.234.231.241)
LAN (Local-Area Network)
A network encompassing a relatively
limited area, such as a building, a
floor, an organization, or a company.
The distance covered typically
ranges from a few meters to a few
kilometers.
LED (light-emitting diode)
A diode that emits light, and is used
as a status indicator.
Log
A record of events occurring during
system operation, along with their
times of occurrence; or, the file
containing such a record. For
example, an error log contains a list
of errors occurring in the system,
while an access log records access to
the server.
MAC (Media Access Control)
address
A number that is assigned to each
NIC (Network Interface Card; also
referred to as LAN card or LAN
board, a NIC is installed in the
computer to allow connection to a
network, and is equipped with a port
for connection to a 100Base-TX,
10Base-T, or other network cable.)
The numbers are not duplicated
anywhere in the world. Used for
physical communication within the
network, they are converted to IP
addresses by the NIC driver software.
With Windows, it is called the
adapter address, and with the
Macintosh OS it is called the network
address.
Mount
To make accessible, either by
connection to the computer itself, or
by placement on the hard disk drive
or other storage medium of a
computer on the network.
Network card
A device installed in a computer or
router to enable connection to a
network. Equipped with a port
(connector) for connection to a
100Base-TX, 10Base-T, or other
network cable. Also referred to as a
LAN card, LAN board, or NIC
(network interface card.
Network system
A system for sharing resources such
as files and printers.
Operating system
Basic software that manages and
controls operation of a computer.
(Example: Windows, Macintosh,
UNIX)
Rack mount
Ordinarily, a 19-inch rack (cabinet)
in which servers or disk units made to
fit such a rack are mounted. A rack
mount kit is hardware for mounting
devices in such a rack.
Router
A repeater for connecting networks
to one another. Determines the
optimum path (route) for forwarding
received data. A router provides
control over a higher level of
processing than a device such as a
hub, and is used in constructing
medium- to large-scale networks.
SMTP (Simple Mail Transfer
Protocol)
A protocol (established set of means
and procedures for conducting data
communication) used for sending
mail over the Internet or an intranet.
Using during transmission by client
PCs, and for communication between
servers. POP (Post Office Protocol)
is used for receiving mail from a
server.)
SMTP server
A server used for sending mail via the
Internet or an intranet.
Server
A computer that provides a variety of
types of service. Examples include
file servers, WEB servers, and
database servers.
Service
A task (also referred to as a process,
viewed from the system as a single
processing unit) or application that
resides in the system and runs in the
background (i.e., constantly runs, but
is not controlled by the user). Also
referred to as a daemon or driver.
Subnet mask
A number that is used for dividing IP
addresses used on a TCP/IP network
into network numbers and host
numbers. This method is used to
allow different networks that are
connected through a router to
recognize that they are different
networks. (Example) When the
subnet mask is 255.255.255.0, in the
IP address 123.234.56.78, the
123.234.56 is the network number,
and 78 is the host number. In this
case, up to 254 terminals can be
connected to the network.
55
Glossary
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