100BASE-T:
The IEEE 802.3u standard Ethernet
specification for 100Mbps (Fast Ethernet) transmission using UTP cable.
10BASE-T:
The IEEE 802.3i standard
specification for 10Mbps Ethernet transmission over UTP wiring, using a star
configuration with a hub at the center.
Access a database within the Microsoft office suite.
Actuator:
The mechanism which moves the
read/write head in a hard disk drive.
Adapter:
The device that connects a piece
of equipment to the network and controls the electrical protocol for communication
with that network; also called network interface card, or NIC.
Adaptive Technology:
An Intel technology (supported in
adapters and switches) that automatically and dynamically customizes product
performance to match network operating conditions, thus helping to optimize
network performance.
ADCCP
(Advanced Data
Communications Control Procedures):
A bit-oriented, ANSI-standard communications link-layer
protocol.
Address Mask:
A bit mask used to select bits
from an Internet address for subnet addressing. Also known as Subnet Mask.
AFP (AppleTalk File
Protocol):
Apple’ s network protocol provides
file server/client access in an AppleShare network.
AGP:
Accelerated
Graphics Port, is a
dedicated graphics port that delivers a fast, smooth true color video image.
ALAP (AppleTalk Link
Access Protocol):
A link access layer (or data link layer) protocol that governs packet
transmission on LocalTalk.
Anti-Virus:
A program or software that monitors and
protects your system against harmful data that causes internal failure of
your computer
APPC (Advanced
Program-to-Program Communications):
A high-level communications protocol from IBM that
enables one program to interact with another anywhere on the network. It
supplies commands for managing a session, sending and receiving data, and
transaction security and integrity (two-phase commit).
APPN (Advanced
Peer-to-Peer Networking):
An addition to IBM’ s SNA communication, APPN provides the most
efficient route for establishing direct communication between users anywhere on
the network.
ARA 2.0 (Apple Remote
Access):
Communication software designed to offer remote access to an
AppleTalk-compatible network via an ARA server.
ARP (Address Resolution
Protocol):
A
TCP/IP protocol used to obtain a node's physical address when only its logical
IP address is known. An ARP request with the IP address is broadcast onto the
network, and the node with that address responds by sending back its hardware
address so that packets can be transmitted. The protocol translates IP
addresses into physical network addresses, such as Ethernet IDs, by converting
the 32-bit IP addresses into the 48-bit physical network Ethernet addresses.
Another TCP/IP protocol which plays a less visible, but equally important role
in the operation of TCP/IP networks. Reverse ARP, or RARP, is used by a
diskless workstation to obtain its logical IP address.
ATM (Asynchronous
Transfer Mode):
A
high-speed networking technology that transfers packets of data to transmit
various kinds of information (voice, video, data).
AUP (Acceptable Use
Policy):
Procedures used to govern the appropriate usage of a network or service.
Authentication:
The process by which a user’ s
identity is checked within the network to ensure that the user has access to the
requested resources.
Auto
Reconstruction/Recovery:
The ability to reconstruct the data automatically either after a hard
drive has been replaced or without user intervention once a failure has been
detected.
Availability:
Also known as system availability
refers to the ability of the system to keep serving even when one of the
component servers fails. Availability is possible with as few as two servers,
but it shows its power when the cluster consists of multiple servers. It is
also the ability to access data even after a disk driver failure without
disrupting any applications.
Backbone:
The part of the network that
carries the heaviest traffic; it connects LANs, either within a building or
across a city or region.
Bad Block Table:
An area on the hard drive disk
reserved for keeping information on failed sectors on the device.
Bandwidth:
The capacity or amount of data
that is transmitted over a network, processor bus, cache bus, or I/O bus.
Normally expressed in bits/second, bytes/second, or cycles/second.
Bandwidth:
The maximum amount of data that a
network cable can carry, measured in bits per second (bps).
Baseband:
A network transmission technique
that uses voltage to represent data; similar to turning a light switch on and
off.
Bisync or BSC (Binary SYNChronous):
A synchronous communications
protocol that transmits binary-coded data between two devices by using a set of
control characters and control character sequences. Unlike asynchronous
transmissions, Bisync requires that both sending and receiving devices are
synchronized before transmission of data is started.
BNC (British Naval)
Connector:
A
connector commonly used with coaxial cable.
Boost:
The addition of UPS battery power
to utility power to increase voltage to an acceptable level (usually 120
volts).
BOOTP (Bootstrap
Protocol):
Protocol that allows an Internet node to discover certain startup information,
such as its IP address. An alternate to RARP.
Bridge:
A device that connects two
networks at the OSI Data Link layer and passes data between them; equivalent to
a two-port switch.
Broadband:
A network transmission technique
that uses radio frequencies on a cable; a broadband cable is typically shared
with other networks or services, such as TV or teleconferencing.
Brownout:
A condition in which utility
voltage falls by more than 10 percent.
Browser:
Client software used to search
information posted on the Web; Netscape* and Microsoft Internet Explorer* are
the most popular browsers.
Buck:
The blocking of overly
high-voltage utility power by a UPS before it reaches the attached devices.
Bus topology:
The physical layout of a network
in which all systems connect to a main cable; also known as linear bus.
Cache Flush:
The act of writing all the data
in the cache to either system memory or the hard drive.
Cd-Rom Compact Disc - Read Only Memory:
A
data
storage medium that uses laser optics rather than magnetic means for reading
data. CD-ROMs read compact discs similar to the audio CDs available in music
store
Channel:
A direct path from one resource
to another. For example, a direct path to a set of hard disk drives or a direct
path from a NIC to another NIC.
CHAP/PAP (Challenge
Handshake and Authentication Protocol/Password Authentication Protocol):
Standard authentication protocol
for PPP connections.
Client:
In a client/server network, a node
(or user workstation) on the network that uses resources provided by a server.
CLNP (Connectionless
Network Protocol):
An OSI network layer protocol that does not require a circuit to be established
before data is transmitted. An example of this type of protocol is UDP.
Clustering:
Linking multiple servers to
ensure system resources will be made available to all users. A clustered system
is transparent to users, seeing no difference between a cluster and a
stand-alone server.
Coaxial cable:
A network cable with good noise
immunity; also known as coax or thicknet.
Collision:
The loss of electronic signals,
or packets, that results when two workstations or two computers attempt to
transmit data simultaneously across a shared medium. Data must be resent as a
consequence.
Collision Domain:
The maximum length of the wiring
media that allows collision detection. For example, the collision domain in
Fast Ethernet using 100BASE-TX is 205 meters.
Command Queuing:
The issuing of multiple commands
and allowing the disk controller to execute these commands out of sequence.
Concurrent
Reconstruction:
The act of reconstructing data of a failed hard drive while the server is still
executing applications and servicing client users.
Consistency Check:
In the case of hard drives, this is
the act of checking the hard drives with a shared parity drive to see if their
XOR’ d data matches.
Cookie:
A piece of information sent by a
Web server to a Web browser. The browser software is then expected to save the
data and send it back to the server whenever the browser makes additional
requests from the server.
Crossover Cable:
A type of networking cable in
which some wires are reversed from one end to the other to join two computers
or two hubs.
CSMA/CD:
The acronym for Carrier Sense
Multiple Access with Collision Detection; a LAN transmission technique
implemented in Layer 2 of the OSI model and employed by 10Mbps Ethernet and
Fast Ethernet.
Data Availability:
The ability to access data from a
hard drive, memory, or cache when required by the processor or resource
controller.
Data Reliability:
The ability of the server to
operate and deliver data without failure over an extended period of time.
Data
Transfers:
The process of moving
information from one source to another, usually from one hard drive to an
another hard drive
Database:
A collection of information organized for easy
retrieval.
Databases are organized into a hierarchy of files, records, and fields.
DDCMP (Digital Data
Communications Message Protocol):
A byte-oriented, link layer protocol that supports half-
or full-duplex modes and either point-to-point or multipoint lines in a Digital
Network Architecture network.
DHCP (Dynamic Host
Configuration Protocol):
A protocol for automatic TCP/IP configuration that provides static
and dynamic address allocation and management.
Diagnostics:
A software program that allows the user
to troubleshoot problems within a computer system
Disconnect:
The act of freeing the SCSI bus
while a hard drive is seeking and reconnecting when the drive is ready to
transfer data.
Diskless workstation:
A system on the network that boots
up its operating system from a remote boot server, rather than locally.
DNS (Domain Naming
System):
A
hierarchical system for assigning unique names to Internet hosts. Special hosts
running DNS server software accept host name queries and return either the IP
number of the desired host or a pointer to another DNS server that
"knows" about the desired host. From the user's point of view, this
resolution of host names to machine addresses usually occurs transparently and
almost instantaneously, allowing the user to reference Internet hosts and
resources symbolically rather than via arbitrary numeric identifiers.
Domain:
An element of the naming
hierarchy on the Internet.
Domain Name:
The unique name that identifies
an Internet site.
Dpi:
Dots per inch, a measurement of resolution
within a monitor or printer
DTDS (Disaster Tolerant
Disk Systems):
A new term from the RAID advisory
board which describes server systems which must be divisible into two or more
zones which cooperate to protect against loss of access to data in the event of
one system’ s complete failure. Protection also is provided against massive
power outages, cooling system failures, and disconnection of power or bus
cables. DTDS+ adds a distance between zones of at least 1Km.
Dumb terminal:
A monitor and keyboard that
displays information only (as opposed to the processing capability of a PC);
usually connected to a mainframe.
Dvd:
digital veratile disc, a large-capacity
optical disc able to store more data than a standard CD.
ECC (Error Correction
Code):
An
algorithm which tests for and promptly corrects errors (in memory) on the fly.
The algorithm normally used will take checksums generated by hardware circuitry
to correct any memory errors greater then one bit.
E-Commerce:
Conducting business transactions
through electronic transmissions between computers. Typically used in reference
to doing business over the internet.
Encryption:
A type of network security in
which information sent over the network is encoded so that only the intended
users can access the information.
Enhanced Error Recovery:
The ability to keep track of
partial failures during the lifetime of a unit and analyze those errors to
locate early potentially fatal failures.
Error Logging:
the ability to store errors
between service periods. Normally stored in a Flash Memory device.
Ethernet:
A LAN cable-and-access protocol
that uses twisted-pair or coaxial cables and CSMA/CD (Carrier Sense Multiple
Access with Collision Detection), a method for sharing devices over a common
medium. Ethernet runs at 10 Mbps; Fast Ethernet runs at 100 Mbps. Ethernet is
the most common type of LAN.
Excel:
A spreadsheet within the Microsoft office
suite.
Expansion
Slot:
An outlet on the
motherboard that is used to connect expansion boards (cards that give the
computer more power and/or features) expansion slots provide a way to improve
the computer system.
Fast Ethernet:
The high-bandwidth networking
technology based on the 802.3 Ethernet standard (100BASE-T); supports 100Mbps
performance, a tenfold increase over original 10Mbps Ethernet (10BASE-T).
Fault Tolerance:
The measurement of a system’ s
ability to recover from a failure.
FDDI: The acronym for Fiber Distributed
Data Interface; a standard for fiber optic cable.
Fiber optic:
A cable that uses light to
communicate; the fastest and most noise-resistant cable available for network
wiring, but also the most expensive.
Firewall:
Hardware and/or software used to
divide a LAN into two or more parts for security reasons.
Flatbed
Scanner:
A computer input device
that converts an image on a piece of paper into an electronic representation
that can be stored in a computer file.
Frame relay:
A high-speed, low-latency packet
switching technology, based on a switched virtual network topology, used for
WANs; popular for LAN-to-LAN connections.
FRDS (Failure Resistant
Data Systems):
A new
term from the RAID advisory board which describes server systems which are
designed to protect against data loss due to any single component failure
within the system and against loss of data to single disk failure. FRDS+ adds
automatic hot disk swap and protection against data loss due to cache failure
or external power failure.
FTDS (Failure Tolerant
Data Systems):
A
new term from the RAID advisory board which describes server systems which must
offer continuous data availability in the event of any single system component
failure. FTDS+ adds data access protection against host and host I/O bus
failure and external power failure. FTDS+ also requires hot swapping of any
major component and the ability to connect at least two hosts using separate
I/O buses.
FTP (File Transfer
Protocol):
A
file-sharing protocol that requires users to log in their name for verification
and security purposes. It allows users to transfer text and binary files to and
from a PC, list directories on the foreign host, delete and rename files on the
foreign host, and perform wildcard transfers between hosts. Designed to work
with TCP/IP.
Full-Duplex:
Using simultaneous two-way
communication between network cards, which effectively doubles the available
bandwidth by transmitting and receiving simultaneously. For example the
bandwidth would double from 10 to 20 Mb per second in Ethernet or from 100 to
200 Mb per second in Fast Ethernet when in full-duplex mode.
Full-duplex:
Allows a packet to be transmitted
and received at the same time.
Gateway:
Any hardware or software that is
used for the purpose of providing access from one system to another.
Gateway:
A network station used to
interconnect two or more dissimilar networks or devices; may perform protocol
conversion.
Gigabit Ethernet:
A developing technology for 1
gigabit per second (1Gbps) Ethernet; equivalent to 1000Mbps and 10 times faster
than Fast Ethernet.
Gigabyte:
A unit of measurement of computer memory,
referring to the capacity of the new larger had drives
Graphics:
Files that consist of visuals, like a scanned
or digitized version of a picture
Half-duplex:
Allows packets to be either
transmitted or received, but not both at the same time.
Hard
Drive:
Consists of a rigid
platter which is fixed inside a sealed casing. A hard drive can store more
information and retrieve data at faster speeds than a diskette. The
permanent storage place for software/programs within your computer.
Hardware:
The physical apparatus of a computer
system.
Home page:
The main page of a Web site and
the first screen that a visitor sees displayed when connecting to that site;
usually has links to other pages, both within that site and to other sites.
HTML:
HyperText Markup Language, the
authoring language of the Internet; used to create Web pages.
Hub:
The central wiring concentrator in
a star-configured network; useful for centralized management, the ability to
isolate nodes from disruption and extending the distance of LAN coverage.
Hyperlinks:
Embedded "hot spots" in
Web pages that allow users to jump from one document to another related
document, regardless of where it "lives" on the Internet.
IEEE:
The Institute of Electrical and
Electronics Engineers, a body that defines standards and specifications.
Internet:
Is a network of networks composed of tens of
thousands of computers.
IP:
Internet Protocol, the part of
TCP/IP that governs packet forwarding.
IPX:
Internet Packet Exchange, a
NetWare protocol that provides connectionless communications between devices on
a network.
ISDN:
Integrated Services Digital
Network, a telecommunications standard for sending digitized voice, video and
data signals over the existing public switched telephone network.
ISO:
International Standards
Organization, a body that promotes computer standards and developed the OSI's
model for network communication.
Keyboard:
A typewriter-like device used to enter,
or input, instructions into the computer
Local Area Network (LAN):
Workstations and computers that
are tied together in a specific work area in the same general location.
Local: Typically refers to devices
attached to the user's workstation, as opposed to remote devices that are
accessed through a server.
LocalTalk:
Apple Computer's proprietary LAN,
based on the AppleTalk architecture.
MAC address:
Unique address assigned to each
active infrastructure end station (including adapters, LAN on motherboard,
switch ports and router ports).
MAC:
Media Access Control, the IEEE
specification for the lower sub layer of the OSI Data Link layer; CSMA/CD and
Token Ring are types of MACs.
Mb:
Megabyte, a unit of measurement of computer
memory of storage equivalent to approximately one million (1,048,576) bytes.
MDI (Medium Dependent
Interface):
The
predefined physical layer interface for 10Mbps Ethernet.
Mhz:
Megahertz, used to measure a computer system's
speed, one MHz is equivalent to one million cycles per second.
MIB (Management
Information Base):
A database of objects that stores information used by SNMP-enabled management
devices.
MII (Medium Independent
Interface):
The
predefined physical layer interface for 100BASE-T.
Modem:
A device that enables data to be transmitted
between computers,
generally over telephone lines but sometimes on fiber-optic cable or radio
frequencies.
Monitor:
A television-like output device for displaying
data.
Motherboard:
The circuit board containing the vital
components of a computer system. The central processing unit is located on the
motherboard and all expansion boards must be connected to the motherboard.
Mouse:
A handheld device which operates by the signals
sent from a rolling ball on the bottom of the mouse. A common input
device for a computer.
Multitasking:
Executing more than one program at a time in an
operating system.
Network:
A group of computers and associated devices
that are connected by communications facilities. Small or large, a
computer network exists to provide computer users with a means of communicating
and transferring data electronically.
Network Operating System
(NOS):
Software
that manages the resources of a network; typically provides file sharing,
e-mail, print services, security measures, etc.
NIC: A Network Interface Card:
see
adapter.
Node:
Each of the individual computers
or other devices on the network.
Online
Service:
Also known as an ISP, a
dial-up service that provides access to the world wide web.
Operating
System:
The master control program
that manages the computer's internal
functions and enables you to direct the computer's operations.
OSI:
Open System Interconnection, a LAN
communication model developed by ISO.
Packet analyzer:
A network diagnostic tool that
hooks into a LAN and analyzes its traffic; capable of capturing a packet,
examining it and breaking it down into its component parts of destination,
origin, protocol, data, etc.
Packet:
A chunk of data bits and
associated information, including source address and destination address,
formatted for transmitting from one node to another.
Peripherals:
A device like a printer or modem that is externally connected to the
computer.
Print server:
An application-specific computer
that manages printers and requests for print services; allows multiple users to
share a network printer.
Print spooler:
A software application, typically
installed on a LAN server, that manages multiple print requests.
Printer:
An input device that transfers information from the computer onto a
sheet of paper.
Processor CPU:
The brain chip of your computer, about the size of a large
stamp.
Protocol:
Any defined set of procedures,
conventions or methods that, when adhered to, allow two devices to
interoperate; used to implement LAN services.
RAM:
Random-Access-Memory,
memory that holds the instructions and data currently being used. Data in
RAM is lost when the computer is turned off.
Remote boot:
A firmware-based program in a
network adapter that asks to have the workstation's operating system downloaded
from a boot server on the network; used by networked diskless PCs.
Remote execution:
The ability to run programs on
remote systems; exporting time-consuming processes to other systems frees up
the local workstation.
Repeater:
A device that regenerates and
amplifies signals to create long-distance networks.
Ring topology:
A network cabling configuration in
which each system is connected in a series, forming a closed loop.
RMON:
An SNMP standard for managing
network devices; lets network engineers with properly configured SNMP
management consoles view packet information on a port-by-port basis.
ROM:
Read-Only-Memory, permanently stored memory
that contains data that can be read but cannot be altered.
Router:
A device that connects two
networks at the Network layer (Layer 3) of the OSI model; operates like a
bridge but also can choose routes through a network.
Server:
A network node that provides
services to client PCs, for example, file access, print spooling or remote
execution.
SNMP (Simple Network
Management Protocol):
A de facto standard for managing network devices, including adapters, switches,
routers, servers and workstations; garners information from various agents.
Software:
Instructions, or programs, that enable a computer to douseful work; contrasted with hardware, or the actual computer.
Sound Card:
A circuit board that can be installed in side your computer case to enhance your system's sound capabilities.
Speakers:
A device that takes the signal from the sound card and makes it audible.
Spreadsheet:
A program that simulates and accountant's worksheet, which is made up of
rows and columns. It's used to calculate budgets and perform financial
analysis.
Star topology:
A network cabling configuration
that uses a central connection point (called a hub), through which all
communication must pass.
Store-and-forward:
A switching technique, used by
bridges and switches, in which complete packets of information are stored in
internal buffers before they are sent to another port.
STP:
Shielded Twisted Pair; a
thin-diameter network wire, wrapped with a metal sheath for extra protection
against electrical interference.
Surge Protector:
An electronic device that absorbs excess
voltage from power surges coming through the outlet where the PC is plugged in.
Switching:
The process by which packets are
received, stored and transmitted to the appropriate destination port.
System Disk or boot disk:
A diskette that contains the files that make an operating
system and can be used to boot, or start, a computer.
TCP/IP:
Transmission Control
Protocol/Internet Protocol; a network protocol that breaks messages into
manageable chunks and verifies that they arrive at the correct destination
node.
Thick Ethernet:
The original Ethernet cable
specification, requiring an AUI connector; noise-resistant, but expensive and
difficult to install.
Thinnet:
(Thin Ethernet) A CSMA/CD network
based on thin coaxial cable (also called thin Ethernet) that requires a BNC
connector; based on the 10BASE-2 IEEE standard.
Token passing:
A network transmission method that
requires a node to have control of a "token" before it can send
messages; typically fairer than CSMA/CD on busy networks, but more complicated
to implement.
Token Ring:
IBM's implementation of token
passing, governed by the IEEE 802.5 standard; second most popular network
topology after Ethernet.
Twisted pair:
A popular and low-cost LAN cabling
method, also commonly used for telephone wiring; uses two wires twisted
together to minimize electrical interference (see STP and UTP).
URL:
Uniform Resource Locator, the
standard way to write the address of a specific site or piece of information on
the Web; for example, http://www.intel.com/.
USB:
universal
serial bus, is a peripheral bus standard that enables automatic detection of
certain peripheral devices, such as scanners.
Utilities:
Software that takes care of housekeeping functions such as hard disk
organization, file management and other matters relating to the performance of
the computer.
UTP:
Unshielded Twisted Pair; a
thin-diameter network wire that is very popular in network cabling
installations.
Video Card:
A circuit board that enables a computer to display text and images on a
monitor.
Virtual terminal:
A terminal emulation program that
makes a workstation appear to be a dumb terminal connected to some remote
system, such as a mainframe.
VLANs:
Virtual LANs; a switching
technology that enables logical segmentation of switched networks, independent
of physical grouping or collision domains.
Web Browser:
A software program, such as Netscape or Microsoft Internet Explorer that
allows the user to view the world wide web.
Wide Area Network (WAN):
A geographically dispersed network
that connects two or more LANs; typically involves dedicated high-speed phone
lines or satellites.
Windows:
is an operating system developed by Microsoft that allows users to access the operations of a computer using a graphical user interface
rather than a character-based interface such as DOS.
Word:
A
word processing
program within the Microsoft office suite.
Word Processor:
the computerized version of a typewriter.
It is a form of applications software that allows users to manipulate text
onscreen and usually offers
features such as spell checking, moving text and various types of formatting.
Workgroup (also called
segment):
A
grouping of workstations, server(s) and any network devices dedicated to
similar functions, using similar applications and/or sharing common resources,
and serving as a sub network entity; members may have a common geography or
function, e.g., engineering, marketing, manufacturing and administration.
Workstation:
For the purposes of this guide, a
personal computer in a network; also called a client.
X.25:
A WAN standard for protocols and
message formats; used to access public packet-switching networks.
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A world-wide-web site which comprehends
