Sampling of IBM Desktop Computers IBM Portable Computer IBM 5100 A larger desktop-sized computer introduced to businesses and educational institutions in September 1975.. Announced in Ja
Trang 1Fiber Optics Illustrated Dictionary
1.410 1~88:
1.610 1995
1.620 1996
1.120 1993
1.130 1988
Basicuser~networkinterface Basic user-network interface -layer
1 specification Prirnary.rateuser-Il~twork interface
PriJnaryrateuser network interface Itlyer.lspecification
1.241.8 1995· Teleaction stage oneservice
description 1.320 1993 ISDN protocol reference model 1.321 1993 B I~DN>prot()colreference Ulodel
and its application
Trang 21.3251993 Reference configurations for ISDN
connection types
1.327 ••1993 B-ISDN functionalarchitecture
1.328·1992 IntelligentNetwork - Service plane
architecture(also Q.1202)
l329 1992 Intelligent Network - Global
functional plane architecture (also
Q.1203)
l331 1997 Internationalpublic
telecommunication numbering plan
1.333 1993 Terminal selection inISDN
1.340·.·1988 ISDNconnection types
1.350.1993 General aspects of quality ofservice
and network performance in digital
networks,including ISDNs
1.3511997 Relationships among ISDN
performance recommendations
1.352 1993 Network perfonnance objectives for
connectioJl processing delays in an
ISDN
1.353 ·1996 Reference events fordefining ISDN
and B-ISDN perfonnance parameters
1.354.1993 Network perfonnanceobjectivesfor
packet mode communicationinan
ISDN
1.355 1995 ISDN 64kbpsconnection type
availability performance
1.3571996 B-ISDN semi-pennanentconnection
availability
1.364<1995 Support of the broadband
cOttJlectionless data bearer serviceby
theB-ISDN
1.370 1991C~:n~estion m~agenlentfor ISDN
FrameRelaying bearer service
1.371 · ·1996 Traffic controlandcongestioncontrol
inB~ISDN
1.372J993 Frante Relayingbearersendee
network-w-nenvorkinterface
requirements
1.373.····.1993 Network capabilities.to support
Universal Personal Telecommunication
(UPT)
L374 1993 Frameworkrecommendation on
"N'etwork capabilities tosupport
multimedia services"
1.376 1995 ISDN network capabilities for the
support of the teleaction service
1.4111993 ISDN user-netw'orkinterfaces·""
referencesconfigurations
1.412.1988 ISDN usernetwork interfaces
-interfacestructuresand access
capabilities
1.413 ·1993 B-ISDN user-networkinterface
1.4141997 Overview of recommendations on
layer 1 for ISDN andB-ISDN
customer accesses
B-ISON - Physical Layer Specification
1.432>1993 B-ISDN user-network
interface-physicallayerspecification
physicallay;erspecification:general characteristics
1.432.2 1996 B-ISDNuser-networkinterface
-physical layer specification: 1S5,S20
~bpsand~t2,080kb~~llperati()n
1.432.3·1996 B-ISDNUSernetWork interface
-physical layer specification:lS44 kbps and 2048 kbpsoperation 1.432.4 1996
B-ISDN~er-networkinterface-physical layer specification:S1,840
kbpsoperation 1.432.5 1997B~ISDN
tiSer-networkinterface-physical layer specification:25,600
kbpsoperation
Multiplexing 1.460 1988 Multiplexing,rate adaption,and
sttpp(lrt°f~~s~~ it,t~~aces
1.464 199t Multiplexing,rate adiiption,and
support ofexisting interfaces for restricted~4 kbitlstransfer capability ATM-related
1.326 1995Functjonalarchitec~ oftransport
networkstiased onATM
1.356 1996 B-ISDNATM layer cell transfer
perfonnance 1.361 1995 B-ISDNATMlayerspecificatioll
1.363 1993 B-ISDN ATMadaptationlayer
(AAL) specification
1.363.1 1.996 ~~..A;1JvI~~9J1:typeI
1.363.3 1996B-ISDNATM adaptation layer
specification: type 3/4AAL
1.363.5 1996B-ISI>N~ at1ap~(lnlayer
specification:typeS·AAL 1.365.1 1993 FrameRelayingservi~e specific
convergencesublayer(FR-SSCS) 1.365.2 1995 B-ISDNATM adaptation layer
sublayers:· service-specific
coor~~~n fU11C1ion~opI'(jvi~~he
connection-orientednetworlc service 1.365.31995 B-ISDNATM adaptationlayer
sublayers:service-specjfic
c()ordinatieJ:lfu~cti0tt~Oprovide~he
connection-oriented transport.service 1.365.4 1996B-ISDN ATMatiaptationlayer
sublayers:service-specific
convergence sublayerfor HDLG
applications
L731 1996 Typesand~eneral.characteristics of
ATMequipment
I.732 1996 Functionalcharacteristics ofATM
equipment I.75 1 1996.<A.synchro~~ustransf~rmode
management ofnetwork element
view
Trang 3Fiber Optics Illustrated Dictionary
monitors are used for both input and output
Key-boards are typically input devices, except for those
that have small LED displays to send configuration,
status, or numeric keypad calculator information to
the user See input device, output device
I1Pinput
i.LINKSee FireWire
IA 1 See implementation agreement 2 See
intelli-gent aintelli-gent
lAB See Internet Architecture Board
lAC 1 See Industry Advisory Council 2 See
Infor-mation Access Company 3 See Infonnation Analy-sis Center 4 See Institute for Advanced Commerce
5 See interactive asynchronous communications
6 See interapplication communications 7 See Inter-net Access Coalition
lADSee Integrated Access Device
IAHC See Internet International Ad Hoc Commit-tee
lAM 1 incoming address message 2 See initial ad-dress message 3 intennediate access memory lANA See Internet Assigned Numbers Authority
Sampling of IBM Desktop Computers
IBM Portable Computer IBM 5100 A larger desktop-sized computer introduced to businesses and
educational institutions in September 1975 The Portable Computer came in a number of configurations, with varying amounts of memory up to 64K (a lot of memory in those days)
at a cost ranging from just under $9000 to almost $20,000 (nearly the price of a house)
IBM Computing System IBM 5110 A small-scale "affordable" computer that was transitional
between high-priced desktops and mainframes, and later systems known as personal computers or microcomputers Announced in January 1978, the 5110 was aimed at a wide portion of the business market, the market successfully penetrated by Tandy!Radio Shack Computers and the later line
of IBM Personal Computers.Itwas available in configurations
of up to 64K of memory
mM Personal Computer IBM 5150 The frrst relatively low-cost personal computer introduced by
mM to realize significant sales to general consumers The IBM
PC was launched in 1981 to compete mainly with Tandy Radio Shack computers making big inroads in both hobbyist and business markets Due to its better reputation for service and its licensing agreements with third parties, mM eventually succeeded in taking the majority business market away from Tandy Tandy did some things right: they opened a chain of computer centers to support the machines and to provide customer service
1980s The PCjr was intended as a low-cost home alternative to the mM Personal Computer XT by IBM
mM Personal Computer XT Extended Technology.AnIntel 8088-based microcomputer,
introduced in 1983 The processing speeds of the various models ofXTs ranged from 4.77 to 10 MHz (turbo XTs), with 16-bit data buses A clock/calendar chip was not standard MicrosoftBASICwas includedin ROM,and the computer could use cassettes for program reads and writes DOS 2.1 was optional, but was needed in order to read and write floppy disk drives
mM Personal Computer AT Advanced Technology An Intel 80286-based 16-bit
microcomputer, introduced in the fall of 1984 by mM as an updated alternative to the IBM XT The processing speed of the
AT was 6 MHz, with 256 kilobytes of memory It came configured with a 1.2-MByte floppy drive, but the 20-MByte hard disk, graphics adapter, and monitor were optional A clock/calendar chip was built in
Trang 4lAPPSee Inter-Access Point Protocol.
IARL See International Amateur Radio League
IARU See International Amateur Radio Union
IBCSee Integrated Broadband Communications
IBMSee International Business Machines
IBM cloneSee IBM-compatible
IBM smaller scale computing systemsA series of
desktop computers has been marketed by IBM for
business, educational, and home markets since the
1970s The frrst models were compact but expensive,
costing nearly as much as a house, and accessible only
to corporations or institutions with larger budgets
However, with the success of the MITS Altair
per-sonal computer, in 1975, and the introduction
oflow-cost desktop computers by other companies, it
be-came clear that the market for computers was
chang-ing and IBM's ballpark price and promotional
cam-paigns had to be adjusted to compete with startup
companies developing new systems
The first small-scale computer system intended by
IBM to significantly exploit the new competitive
market was the IBM 5110, announced in 1978 This
lower cost successor to the IBM 5100 was
unsuccess-ful in capturing popular attention, however, as it was
overshadowed by the Tandy/Radio Shack TRS-80
and Apple computers and, to some extent, the
Com-modorePET
Thus, in the early 1980s, IBM was scrambling to
cap-ture business and home markets, as demonstrated by
their release of the IBM Personal Computer and the
IBM PCjr By the mid-1980s, they had successfully
recaptured a large portion of the business market,
however; the home market was still showing a
pref-erence for Apple, Atari, and Commodore-Amiga
computers, while the educational market was largely
based on Apple computers
In the graphics industry, professionals were
over-whelmingly selecting Apple Macintoshes over IBM
computers due to the better graphics hardware and
software available for desktop publishing and
pre-press At the time, ffiM computers were difficult to
network and tended to be equipped with
low-resolu-tion monitors and text-based operating systems.It
was not until about 1994 that IBM PCs made
signifi-cant inroads in the publishing service bureau markets
and, even then, companies adding IBM computers
tended to hang on to Macintosh computers for
large-scale printing jobs such as posters, billboards, etc.,
where reliable output and good printer drivers were
important Ironically, the reason IBM and
IBM-li-censed third party computers became better suited to
the needs of the graphics sector was because of the
market force for better games machines Computer
games require substantial computing resources,
in-cluding more memory, faster processors, and better
graphics and sound With the exception of better
sound, these are the same capabilities needed by the
graphics industry, which they finally got in a
round-about way
Over time, in business markets and, eventually, home
markets, IBM computers prevailed Part of the
rea-mid-1980s was IBM's decision to license the tech-nology to third-party manufacturers Thus, IBM
"clones" and IBM "compatibles" became prevalent
in the mid-1980s, but ffiM computers were preferred until about 1987, when it became clear to consumers that the quality of some of the clones was superior to IBM systems and, in many cases, less expensive Once again, IBM had to adjust their marketing and manufacturing to compete with a market that was rap-idly changing and evolving
By the late 1980s, desktop computers were beginning
to supersede mainframes for many types ofcomput-ing applications in spite of the insistence of diehard mainframe reps that mainframes were here to stay Since the mainstay of IBM up to this time had been their medium- and large-scale computers, it was
im-~~~;~;~i:!~r~il~~:~~~~~~~~:r~;:more powerful than many of the main- and • miniframes sold to institutions a decade earlier for tens ofthousands or millions ofdollars This remark-able trend for less expensive computers to have more and more powerful capabilities continues to this day
In chronological order, the Sampling of IBM Desk-top Computers chart includes a brieflist ofearly ffiM computing systems See ffiM-compatible
IBM Token-RingSee Token-Ring network
IBM-compatibleAde facto marketing term used by various companies to promote a desktop computer incorporating licensed Intel-based International Busi-ness Machines (IBM) technology to the extent that most, or virtually all software compatible with IBM personal computers would run on the third-party IBM-compatible machines
IBNInstitut BeIge de Normalisation ABelgian stan-dards body of the Minister of Economic Affairs, lo-cated in Brussels It is also involved in certification and accreditation activities IBN is associated with the Comite Europeen de Normalisation (CEN) and ISO http://www.ibn.be/
IDS 1 See intelligent battery system 2 See Intelsat Business Service
IC 1 See integrated circuit 2 See intercom 3 terexchange carrier See Inter Exchange Carrier 4 in-termediate cross-connect
iCalendar, iCalAn Internet calendaring and sched-uling core object specification submitted as a Stan-dards Track document by Dawson and Stenerson in
1998 The iCalendar spec is intended to provide a foundation for developing and deploying interoper-able calendaring and scheduling services over the Internet Since a number ofdifferent proprietary prod-ucts from commercial vendors were beginning to be extended for use over the Net, a need was seen for defining a common format for the exchange of cal-endar and schedule information Group or personal information managers may exchange information through the MIME content type defined in the speci-fication
As a result ofinterest in this most basic and common
Trang 5Fiber Optics Illustrated Dictionary
type of application for Internet use, the Internet
En-gineering Task Force (IETF) initiated a calendaring
and scheduling working group (CALSCH) Other
protocols with a direct relationship to iCalendar
inter-operability have been defmed, most of them arising
from discussions ofthe CALSCH CALSCH not only
described and submitted specification drafts, but also
administered interoperability testing The work of
CALSCH has also come to the attention of working
groups developing separate but somewhat related
protocols and formats, including the IPTEL working
group
The iCalendar spec is based upon an earlier vCalendar
specification and has been further described inUML
by Michael Arick as to its components, properties,
and parameters related to the properties In 1999,
Mahoney and Taler submitted a draft of the
Imple-mentors' Guide to Internet Calendaring to aid in
un-derstanding the iCalendar effort and the relationships
of the different protocols to facilitate the creation of
conformant applications
Progress towards a final embodiment dragged
some-what and the specification gainedincomplexity over
time Market-sensitive vendors began to be wary not
only ofthe complexity but also ofthe time it was
tak-ing for the effort to solidify CALSCH members
even-tually acknowledged that it might he best to simplify
the project and denote some areas ofiCalendar
imple-mentation as optional rather than mandatory, a move
that sparked some renewed interest See RFC 2445
iCALA Web-based commercial software calendar/
scheduling utility available in personal and
profes-sional editions Demo versions may be downloaded
free from the Web
lealAnX-based calendar/scheduling program
devel-oped by Sanjay Ghemawat Version 2.0 was released
in 1995 C++ Source code may be downloaded from
the Web and through FTP
ICALSee Internet Community at Large (natural
his-tory collections project)
ICALEPInternational Conference on Accelerator
and Large Experimental Physics
ICANN See Internet Corporation for Assigned
Names and Numbers
ICAPI1 International Call Control API 2 See
In-terface Control Application Programming InIn-terface
ICCDSee Internet Configuration Control Board
ICeeSee Internet Channel Commerce
Connectiv-ity Protocol
ICCF 1.See Interexchange Carrier Compatibility
F0-rum.2.International Civic Communication Forum
A nongovernmental organization (NGO) in the
Ukraine, somewhat analogous to a nonprofit
organi-zation' that is assisting in providing guidelines for the
establishment of further NGOs as democratic
insti-tutions 3 See International Correspondence Chess
Federation
ICEASee Insulated Cable Engineers Association,
Inc
ICELAN 2000A commercial software automation
control system developed bylEe.It is a graphical
network management and control product to provide
support and control over LONWorks nodes and ap-plications Based on Peak Components, this Win-dows-based software enables LONWorks users to install, maintain, schedule, and configure LONWorks networks See LONWorks
Birefringent Iceland Spar Mineral
Raw, transparent calcspar, called Iceland spar, prior
to cleavingfor use as refracting lenses.
A rendered illustration ofthe birefingent refractive properties ofIceland spar (right), an anisotropic ma-terial, as compared to other common translucent
iso-tropic materials such as glass (left) The directional crystal-like structure ofcalcite causes light to be re-fracted in two directions, resulting in a double image when viewed through the appropriate plane.
Iceland spar, calcspar(symb.-CaC03)Acommon, semihard, soluble, somewhat brittle, crystal-like eral of the calcite group Calcite is one of three min-eral phases of calcium carbonate It is the primary constitutent of limestone The transparent form, known as Iceland spar or calcspar, was predominantly found in Iceland until sources began to dwindle and Mexico became a predominant supplier
Depending upon impurities, calcspar may be pink-ish, amber, or bluish and semitransparent Impurities such as manganese enhance the mineral's ability to fluoresce under ultraviolet light
Iceland spar resembles crystals when cleaved, as the faces within the material are rhomboid with blunted comers.Incrystalline form, the structures are spiked Iceland spar was widely used in optical instruments for almost 200 years
Calcspar has the interesting property of doubling an image seen through certain planes Combining two pieces will yield four images, depending upon the orientation of the pieces and the viewer
In1669, Danish physicist Rasmus Bartholin received
a piece of calcspar from Iceland and studied its
Trang 6ing his findings in 1670 In 1690, Dutch physicist
Christiaan Huygens enlarged upon the study
ofbire-fringence in a published treatise and described light
emanations in terms ofspherical wavelets These
ob-servatierns and later ones by W Wollaston and
L Malus were significant in the understanding
ofpo-larization and the wave nature of light
In 1828, Nicol bonded two pieces ofIceland spar
to-gether with Canada balsam, which has a slightly
dif-ferent refractive index from the spar, thus
develop-ing a polarizdevelop-ing prism component This became a
mainstay ofpolarimeters and microscopes for almost
100 years Calcspar is now used less frequently in
specialized optical instruments, usually for
polariz-ing light in the near-infrared and visible spectra See
birefringent, Nicol prism, refraction, Ulexite
ICISee Interexchange Carrier Interface
ICIASee Information and Communications
Indus-try Association, Ltd
ICMSee Integrated Call Management
ICMPSee Internet Control Message Protocol
ICO See International Commission for Optics in
AppendixG
ICO Galileo Galilei AwardAn international award
given annually for outstanding contributions to the
field of optics achieved under relatively unfavorable
circumstances In addition to the award, which was
established in 1993 and has been awarded since 1994,
the Italian Society of Optics and Photonics (Societa
de Ottica e Fotonica) donates a silver medal to the
recipient See ICO Prize
ICO Global CommunicationsA Craig McCaw
company which at one time was planning a merger
with Teledesic, LLC, the "Internet in the Sky" project
underway by Gates and McCaw This proposal was
discontinued in late 2001 See New ICO
ICO PrizeAninternational award given annually to
an individual who has made a noteworthy
contribu-tion to the field of optics that has been submitted for
publication prior to the nominee reaching the age of
40 The award was established in 1982 and is
admin-istered by the ICO Prize Committee In addition to a
cash award, the Carl Zeiss foundation donates an
Ernst Abbe medal to the ICO Prize winner See Abbe,
Ernst; ICO Galileo Galilei Award
iCOMPIntel Comparative Microprocessor
Perfor-mance index A simplified means of evaluating and
expressing relative microprocessor power, introduced
by Intel in 1992 Intel, as a major vendor of
micro-processing chips, sought a straightforward way to
convey processor information to purchasers The
iCOMP is an index rather than a benchmark in a
tech-nical sense, as it narrowly describes instruction
ex-ecution speed (not clock speed) Benchmarks involve
sophisticated and careful evaluation of many
perfor-mance factors, whereas an index is a basic indicator,
in this case, a compilation based on four
industry-standard benchmarks, without taking into
consider-ation other aspects ofthe system architecture,
includ-ing video display, device addressinclud-ing, etc
iCOMP is expressed on a comparative scale, which
cessor as a baseline, assigning it a value of 100, with subsequent processors rated relative to this
icon 1 Pictorial representation, symbolic image, emblem 2 In telecommunications documents and applications, a symbolic image, usually small and abbreviated, representing an object, program, state,
or task Visually similar iconic representations are sometimes used to show different aspects or states
of the same thing, such as aghostedicon to show something is in use or an iconized version of an ap-plication symbol to show something is loaded and available Icons are used extensively in documenta-tion and graphical user interfaces (Gills) to represent concepts or contents Some are specific to an appli-cation or platform, but some are common enough to
be recognized across a variety ofsystems, e.g., folder
~~~~~er::;:'~i~;r:~=:ications networkbeing it.if:;
put into place by ICO Global Communications See :1,:1:'·
NewICO
ICONTEC Instituto Colombiano del Normas Tecnicas A Columbian technical standards body
ICTA1 Idaho Cable Telecommunications tion 2 Indiana Cable Telecommunications Associa-tion 3 See Independent Cable & Telecommunica-tions Association 4 See International Center for Technology Assessment 5 International Christian Technologists' Association 6 See International Com-mission on Technology and Accessibility 7 Interna-tional Conference on Technology and Aging
ID1 identification, identifier 2 See input device
3 See integrated dispatch 4 intermediate device
IDA1 See integrated data access 2 integrated digi-tal access Digidigi-tal systems intended to facilitate ac-cess to networks and/or application or information sources The phrase is usually used with reference to systems where a number of features have been inte-grated into one easily used unit, such as a portable scheduler with a built-in wireless modem 3 intelli-gent drive array See RAID
IDAISee Accessible Information on Development Activities
IDCMAIndependent Data Communications Manu-facturers Association.Anindependent trade organi-zation representing the interests ofindependent com-munications manufacturers The IDCMAhas spoken out on some ofthe FCC-related rulings regarding new technologies that mayor may not be considered as customer premises equipment
IDESee integrated development environment
IDE devices and controllersIntegrated Drive Elec-tronics.Acontrol mechanism and format for com-puter hard disk drive devices developed in 1986 by Compaq and Western Digital IDE provides data transfer rates of about 1 to 3 Mbytes per second, de-pending upon other system factors, including the data bus On common Intel-based microcomputers, the IDE uses an intenupt interface to the operating system
IDE has been highly competitive with the SCSI stan-dard, another very common drive format To get the production costs down, and becausemanyIntel-based
Trang 7Fiber Optics Illustrated Dictionary
computers in the early 1980s did not come standard
with controllers for extra peripherals, the IDE
con-troller mechanism was incorporated into the drive
Each controller can handle two drives, a "master" and
a "slave" (compared with seven, including
control-ler, for SCSI)
IDE is more limited than SCSI (fewer devices can
be chained, smaller addressable space, IRQs
neces-sary, not compatible with RAID systems, etc.), but it
is also less expensive and has become widely
estab-lished In order to overcome some of its limitations,
a number of enhanced IDE formats now exist
Most workstations and Motorola-based desktop
com-puters (Suns, SOls, Amigas, most Apple
Macin-toshes, NeXTs, and others) include SCSI controllers
on the basic machine, making it unnecessary to
pur-chase a separate drive controller to add SCSI
periph-eral devices to the computer Some of the newer
Macintosh and PowerMac computers support both
SCSI and IDE Most Intel-based desktop computers
come with IDE controllers on the basic machine and
SCSI controllers can be purchased as options See
FireWire, hard disk drive, SCSI
IDEA See International Data Encryption Algorithm.
iDEN integrated Digital Enhanced Network Digital
phone technology developed and marketed by
Motorola for workgroups The phones may be used
like two-way radios over a cellular network, thus
overcoming the distance limitations of conventional
portable two-way radios while also offering other
services such as phone, messaging, and data
trans-missions Fax and Internet access capabilities are also
provided on data-ready iDEN units The system is
based on the concept of multiple workgroups
com-municating within a private virtual network that is
part of a larger common infrastructure See Enhanced
Specialized Mobile Radio
IDEN integrated digital electronic network.
identifier ID I In database management, a keyword
used to locate information, or a category of
informa-tion 2 In programming, a variable name, extension,
prefix, suffix, or other device to provide a means to
easily recognize an element, or distinguish it from
others
IDF intermediate distribution frame See distribution
frame
IDL See Interface Design Language.
IDLC See Integrated Digital Loop Carrier.
idle In a state ofreadiness, but not cUrtently activated.
Idle is often used as a power-saving measure, and may
be a state in which only minimal power is used by
the system until full power is needed, as in laptops
that power-down the monitor and hard drives when
they are not in active use
idle channel code A repeated signal that identifies a
channel that is available, but not currently in active
use See idle
idle channel noise Noise in a communications
chan-nel that can be heard or occurs when no transmissions
are active For example, low level hums can often be
heard in phone lines when no one is talking, but are
not noticed when talking continues
idle line cutoff In computer networks, it is not
un-common for Internet Services Providers (ISPs) or network administrators to set the system to log off any clients (machines or applications) that are inac-tive for longer than a specified period of time (e.g.,
15 minutes) This frees up abandoned terminals or modem lines that are no longer in use
idle signal I In networking, a channel which is open
and ready, and which may besendingan idle signal, but through which no active or significant transmis-sions are occurring 2 Any signal in a circuit intended
to signify that no significant transmission is cUrtently
in progress An administrative tool to allow poten-tial users, operators, or operating software to detect available lines and put them into use, or to compile and record usage statistics for further evaluation and tuning of a system See idle channel code
IDML See International Development Markup
Lan-guage
IDMLInitiativeAcollaborative initiative to improve global information exchange using XML in an inter-national context through use of a standardized Inter-national Development Markup Language (IDML) http://www.idmlinitiative.org/
IDN See Integrated Digital Network.
IDSCP See Initial Defense Communications
Satel-lite Program
IDIV See Improved Definition Television.
IDU See Interface Data Unit.
IEC I See Inter Exchange Carrier 2 See
tional Electrotechnical Commission 3 See Interna-tional Engineering Consortium
IEEE Institute of Electrical and Electronic Engineers,
Inc The world's largest electrical, electronics, and computer engineering/computer science technical professional society, founded in 1963 from a merger
of the American Institute of Electrical Engineers (AlEE) and the Institute of Radio Engineers (IRE) IEEE is a respected and influential organization that serves about a quarter of a million professionals and students in almost 200 countries IEEE's activities are broad-reaching, including standards-setting, publica-tions, conferences, historical preservation and study, and much more See American Institute ofElectrical Engineers, IEEE Standards Association, Institute of Radio Engineers, Organizationally Unique Identifier http://www.ieee.org/
IEEE Canada Institute of Electrical and Electronic
Engineers of Canada The Canadian arm of the well-known IEEE, organized across the country into groups based on geographic regions
http://www.ieee.ca/
IEEE History Center The historical archive of the
IEEE, including about 300 artifacts and a number of oral histories The IEEE includes among its early members some of the pioneer inventors in the tele-communications field, including Thomas Edison and Nikola Tesla It works in cooperation with the IEEE library in which IEEE publications are stored See IEEE
IEEE Standards Association IEEE-SA An
interna-tional organization serving individual and corporate
Trang 8IEEE-SA focuses on full consensus standards
pro-cesses as well as innovative policies for standards
development It is affiliated with the IEEE and is
empowered to formulate and promote international
engineering standards to further globally beneficial
applications oftechnology Membership in IEEE-SA
is not necessarily a requirement to participate in a
standards working group See IEEE
IEEE 802.11Standard for wireless local area
net-works (LANs) adopted in June 1997
lENSee Internet Experimental Note
IES, IESNASee Illuminating Engineering Society
ofNorth America
IETFSee Internet Engineering Task Force
IFintermediate frequency
IFax deviceAnInternet-interfaced device capable of
sending and/or receiving Internet facsimiles through
existing Internet mail mechanisms as defined in
RFC 822 and RFC 1123 In general, IFax formats
must be MIME compliant
IFax devices can also be used as gateways between
the Internet and G3Fax (traditional) phone-based
fac-simile machines, with the IFax configured to handle
the connection and dialup and any authentication
nec-essary to prevent undue cost or unauthorized use An
IFax device can serve as a mail transfer agent (MTA)
for one or more G3Fax devices In general, Simple
Mail Transfer Protocol (SMTP) should be used for
such applications, although dedicated servers may use
POP or IMAP The IFax specification was developed
by the IETF Fax Working Group and described as a
Standards Track comment in 1998 See facsimile
for-mats, G3Fax, TIFF-FX, RFC 2305
IFCMSee independent flow control message
IFD See image file directory
IFIPSee International Federation for Information
Processing
IFRB See International Frequency Registration
Board
IFTLSee Fiber in the Loop, Integrated
IFWPSee International Forum on the White Paper
IGCintelligent graphics controller
IGMPSee Internet Group Multicast Protocol
ignitionLighting, kindling, applying a spark so as
to inflame or provide sufficient heat or current to set
off a chain of events
IGPSee Interior Gateway Protocol
IGRPSee Interior Gateway Routing Protocol
IGTIspettorato Generale delle Telcomunicazioni
General Inspectorate ofTelecommunications in Italy
IGYInternational Geophysical Year
IIA 1 See Information Industry Association 2 See
Irish Internet Association
DCASee International Intellectual Capital Codes
Association
llIA 1 See Integrated Internet Information
Architec-ture 2 See International Internet Industrial
Associa-tion 3 See Internet Information Infrastructure
Archi-tecture
IIR Interactive Information Response
HOP Internet Inter-ORB Protocol Awire-level
com-Broker
IISP 1 See Information Infrastructure Standards Panel 2 Interim Interswitch Signaling Protocol A basic call routing scheme which does not automati-cally handle link failures; routing tables established
by the network administrator are used instead IITCInformation Infrastructure Task Force IJCAIInternational Joint Conferences on Artificial Intelligence An international biennial forum (in odd-numbered years) held since 1969
http://ijcai.org/
ILDinjection laser diode See laser diode
ILECSee Incumbent Local Exchange Carrier ILLIACI Ahistoric large-scale computer introduced
in 1952 by the University of Illinois It consisted of vacuum-tube technology and performed 11,000 ar-ithmetical operations per second See ENIAC, MA-NIAC
ILLIAC IIThe successor to the ILLIAC I, the ILLIAC IT was introduced in 1963 It was based upon transistor and diode technology and could perform
up to 500,000 operations per second
ILLIAC InThe ILLlACillwas introduced in 1966
It was designed to process nonarithmetical data, and
so was a departure from ILLIAC II, a special purpose machine
ILLIAC IVBased on the new semiconductor tech-nology, the ILLIAC IV was introduced in the early 1970s It was logically designed after the Westing-house Electric Corporation's SOLOMON computers developed in the early 1960s The ILLlAC IV con-sisted of a battery of 64 processors which could ex-ecute from 100 million to 200 million instructions per second It was significant not only for its speed, but also for the ability of its multiple processors to per-form simultaneous computations The services ofthe ILLIAC IV were made available to other institutions through high-speed phone line timesharing illuminatorA radiant energy source that provides light which may be used directly or channeled through fiber optic filaments to another location Il-luminators commonly light buildings, microscopic stages, projectors, lighthouses, signal systems, cali-bration and aiming systems, and, when modulated, provide communications signals that can be sent over long distances through a lightguiding channel Com-mon sources of illumination for fiber optic systems are lasers and light-emitting diodes (LEDs) Illuminating Engineering Society of North AmericaIES, IESNA A leading technical authority
on illumination For almost a century, the IESNA has been providing expertise on lighting practices through programs, publications, and services Members in-clude engineers, educators, scientists, manufacturers, and utility services personnel
http://www.iesna.org/
ILMISee Interim Link Management Interface IMA Interactive Multimedia Association of Malay-sia Information about this standards-setting organi-zation is available on the Web
http://wwwl.jaring.my/cornerstone/ima/about.htm
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IMACSee Isochronous Media Access Control
image antennaA hypothetical antenna, used for
mathematical modeling, defined as a mirror-image of
an above-ground antenna, located below the ground
symmetric to the surface, at the same distance as the
actual antenna is above the surface
image dissectorA vacuum tube-based image
scan-ning mechanism about the size and shape of a long
flashlight, developed by television pioneer Philo T
Farnsworth in the early 1920s It was a type
ofpho-tomultiplier component enabling the transmission of
straight line images by sweeping the image past an
aperture at about thirty times per second When
Farns-worth applied for a patent for an electronic television
system, in January 1927 (U.S #1,773,980), the
de-sign included the "image dissector tube."
By the 1930s, Farnsworth had improved the
technol-ogy so that it could transmit 300 lines per frame,
leap-frogging over his competitor, John Logie Baird, in
the U.K At this point, Farnsworth began
demonstrat-ing and promotdemonstrat-ing his device in Europe Gaumon
British licensed the technology, with Baird in charge
of incorporating the tube into a new television
sys-tem Baird took an unexpected path and hybridized
Farnsworth's electronic system with a mechanical
system and produced a 700-line image by 1935
The technology caught the attention of other
scien-tists.AsRCA was working to simplify and improve
upon photomultipliers, J Pierce and W Schockley
(coinventor of the transistor) at Bell Laboratories
were working on the concept as well, in the late
1930s R Winans joined Pierce in the effort and they
published their results in the early 1940s The mecha-nisms developed at that time are similar to those in use today
The invention and its evolutionary descendents was
an important component in image display/reading products and some military guidance systems for sev-eral decades until solidstate components began re-placing vacuum tubes Working as a television pickup
it made it possible to broadcast film programs for tele-vision broadcasting It differed from Zworykin's Iconoscope in light sensitivity and storage capabil-ity and thus was not as well-suited as the Iconoscope for broadcasting live performances
Over the years, image dissectors became more com-pact than Farnsworth's original tube, measuring about 2-in diameter by the 1940s and halfthat by the 1960s, while retaining the same general structure By the 1950s, the basic flashlight-shaped image dissector had been integrated with a bulbous camera tube for commercial television sets
Vacuum-tube-based image dissectors have been in-corporated into optical readers, electronically scanned spectrometers, industrial defect detectors, and elec-tronic astronomical star trackers Modem versions have been used to image synchrotron radiation emis-sions in conjunction with phase-locked radio fre-quency signals, similar to the functioning of a stro-boscope The image can be scanned and viewed on
an oscilloscope
Image dissectors have applications in current optical systems Goldstein et a1 have developed an acousto-optical laser-scanning confocal microscope incorpor-Fiber Optic Illumination Source and Beam Conditioning
l'
10 5"
This example ofa patented illumination source for fiber optic systems illustrates many ofthe basic concepts and components related to fiber light sources The initial light source is provided by an array oflight-emitting diodes (3, 3') from which the light beams propagate outwards (like flashlight beams) The light beams encounter an array of lenses matched to the LEDs The lenses align the beams so they travel in congruent rather than varying paths (colli-mation) The collimated beams then pass through a transparent Fresnel lens(8), with facets angled relative to the center to amplify and "concentrate" the beam (like a lighthouse assembly) This conditioned beam propagates to-ward the connectorfor the light pipe(9)where afiber orfiber bundle can be coupled to the light source [Maas et al., U.S patent #6,402,347, awarded June 2002.J
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motion inside MRI and PET medical imaging
scan-ners and image dissectors are used for certain
photo-nic space-based star sensors
See Baird, John; Farnsworth, Philo; iconoscope;
pho-tomultiplier; television history; Zworykin, Vladimir
Farnsworth Dissecting Target Tube
Farnsworth continued to make adaptations to the
dissecting tube technology hefirst conceived in 1922.
In July 1930, he described a more sensitive dissector
target tube,with amplification by secondary emissions
application for an electron discharge apparatus for
the electrical scanning and transmission oftelevision
images.
lM'ENI'OIt,
Excerpts adaptedfrom the patent show the
dissec-tor tube (left) and a detailed view of the target
com-ponent (right) housed at the top ofthe dissector tube.
The image to be transmitted is focused through a
photosensitive surface on the face ofa front-silvered
mirror (12) [U.S patent #1,941,344.]
image file directoryIFD A data file structure
pro-viding location information for image data in the form
of image information and data pointers In a TIFF
raster image file, for example, the IFD is an ordered
sequence of tagged fields that begins on a word
boundary somewhere after the header data As more
than one raster image may be in a TIFF file (as in a
multi-page document or document with different
ver-sions ofthe same image), there can be more than one
tures or as linked lists See TIFF
image intensifierIn the optical spectrum, a device that increases the luminance of an image The tech-nology was first pioneered by French researchers in the 1930s and significantly developed two decades later by U.S Army Corps engineer John Johnson un-der the direction ofRobert Wiseman
Image intensification in the optical spectrum is ac-complished by means of a photocathode in a photo-multiplier electron tube that amplifies the signal and turns it back into an image with increased luminance Outside the optical spectrum (e.g., X-rays), the radi-ant energy is first passed through a scintillator, that converts the high-energy rays to frequencies in the optical spectrum, from which a photocathode can sense the signals For imaging over a larger area than
sometimes also used to take the image out of the de-vice and feed it into a computer or remote viewing device The contrast or sharpness of the image may
be processed with computer algorithms in conjunc-tion with image intensificaconjunc-tion, prior to reconstruc-tion of the intensified image
The range of frequencies and the particular part of the spectrum that are intensified depend upon the sys-tem and the application The syssys-tem may be config-ured to intensify only certain parts ofan image within stated bounds
The three basic components ofan image intensifier
proportion to the light falling upon the cathode, a microchannel plate (2), which is a finely fused array ofglass channels coated with a resistive layer, and a phosphor screen (3) The phosphor screen typically emits light into a light-guiding component such as a fiber optic taper (4) which may be coupled to a charge coupled device (5).
The microchannel plate (MCP) provides a cascad-ing amplifycascad-ing effect to the electrons provided to it by the photocathode The phosphor screen converts the amplified electron signal back into photons.
The fiber optic taper may be substituted with a fi-ber opticfaceplate (a fifi-ber optic a"ay similar inform
to the microchannel plate) and mayfurther include a
twist in the fiber filaments to invert the image.
Image intensifiers are typically used with weak light