DAB/DAR=
Digital Audio Broadcast and
Digital Audio Radio broadcasting
in digital formats via satellites and fiber optic
cable. (See also Networks
and DCC)
DAC= Digital
Analog Conversion hardware that converts
digital signals into analog form. (See also ADC,
Scan converter,
Modem,
and Video)
Daemon = Disk And Execution MONitor
programs that are not initially executed but lie
in wait for certain contingencies to occur. Daemons
are extremely common in UNIX operating systems.The
slightly revised form Demon refers to the program
itself whereas Daemon refers to an operating system
process. See also HTTPd.
Darwin = (See Operating System.)
DAT= Digital
Audio Tape used for recording computer
disc files onto a cheap backup and storage medium.
DAT tapes are contained in small cartridges that
are the cheapest means of storing vast amounts of
data. For example, a cartridge smaller than the
palm of an adult hand can hold two or more gigabyes
of data. Popular manufacturers of DAT backup tape
drives include Sony and Hewlett-Packard.
Data Discman=
(See Games)
Database= A computer file or system of data organized in records
and fields for fast retrieval and ease of updating.
For an overview of network database trends see http://www.trinity.edu/rjensen/260wp/260wp.htm.
Also see CFML,
Concurrency
Control, DTP,
GainMomentum,
Grid
Computing, JDBC,
MDA,
Middleware,
Relational
database management, SAP,
Resource
Description Framework, and 4GL Database
Languages.
Key
database system and enterprise resource planning
(ERP) system web sites for large-scale systems are
listed below:
Some
of the above systems are stronger on personnel
management utilities and weaker on database technologies.
Others are stronger on database technologies and
weaker on personnel management. In all cases,
installation of a system is no piece of cake.
In some cases it can take years and millions of
dollars to get a system in place. But in
those instances these larger systems are the only
feasible alternatives.
Smaller-scale
database systems are reviewed by D.C. Hayes and
J.E. Hunton in the Journal of Accountancy, January
1999, pp. 61-69. These are useful for small
business and small departments within large businesses.
Sometimes it is easier to build a small database
system than to fool with a large system to handle
smaller jobs. Smaller-scale database software
packages include the following:
Microsoft
is promising a greatly improved MS Access that will
probably take over the smaller-scale database market
like Excel took over the spreadsheet market.
One advantage of MS Access is the way it integrates
with other MS Office programs such as Excel.
Networked
databases are exploding in popularity across the
Internet. For a review, see http://www.nytimes.com/library/tech/99/03/circuits/articles/18bots.html
. Microsoft is promoting ActiveX Data Objects
(ADO). The following is a quotation from http://www.microsoft.com/data/ado/prodinfo.htm
:
The
ActiveX® Data Objects (ADO) programming model represents
the best of the existing Microsoft data access programming
models. If you are familiar with Data Access Objects
(DAO) or Remote Data Objects (RDO), you will recognize
the interfaces and will be able to work with them
very quickly. You will also notice considerable
improvements in the model, and tasks that were awkward
in previous models have either been fixed or eliminated
from the ADO model.
The
ADO objects provide you with the fastest, easiest
and most productive means for accessing all kinds
of data sources. The ADO model strives to expose
everything that the underlying data provider can
do, while still adding value by giving you shortcuts
for common operations.
ADO
is Microsoft's strategic, high-level interface to
all kinds of data. ADO provides consistent, high-performance
access to data, whether you're creating a front-end
database client or middle-tier business object using
an application, tool, language, or even an Internet
browser. ADO is the single data interface you need
to know for 1- to n-tier client/server and Web-based
data-driven solution development.
ADO
is designed as an easy-to-use application level
interface to Microsoft's newest and most powerful
data access paradigm, OLE DB. OLE DB provides high-performance
access to any data source, including relational
and non-relational databases, email and file systems,
text and graphics, custom business objects, and
more. ADO is implemented with a small footprint,
minimal network traffic in key Internet scenarios,
and a minimal number of layers between the front-end
and data source-all to provide a lightweight, high-performance
interface. ADO is easy to use because it is called
using a familiar metaphor - the OLE Automation interface,
available from just about any tool and language
on the market today. And since ADO was designed
to combine the best features of, and eventually
replace RDO and DAO, it uses similar conventions
with simplified semantics to make it easy to learn
for today's developers.
Related
to ADO the Microsoft®
Remote Data Service (RDS) for distributing data
on the Internet. You can read the following
at http://www.microsoft.com/data/ado/prodinfo.htm#Face
:
RDS
Overview
Multiple
sources...One control...Rich user experience...RDS
is just that simple! The Microsoft® Remote Data
Service (RDS) is your source for distributed data
access through the Web. RDS makes full-featured,
data-centric Web applications a reality by combining
data manipulation of retrieved data, efficient client-side
caching, and support for data-aware ActiveX® controls
with an elegant and powerful programming model.
RDS
is Bringing Data Access to the Web!
RDS
goes beyond the current generation of Web data access
tools by allowing clients to update the data they
see. Using drop-in ActiveX data controls, such as
grids, lists, and combo boxes, developers can deploy
sophisticated user interfaces that allow end users
to view and change data with a minimum of programming.
End users are no longer restricted to staring at
a static HTML results table. With RDS, they may
now alter, add, and delete data they have queried
and retrieved. In addition, all changes are buffered
locally, and can be submitted to the server for
inspection, processing and storage in the database.
The
benefits of traditional client/server technology
have migrated to the Web, and the read-only, static
client is a thing of the past. By providing a local
data cache, the end user is now able to navigate
through large data sets without costly server round
trips.
RDS
provides the ability to invoke remote objects over
HTTP and DCOM, enabling programmers to develop distributed
Web applications that effectively partition application
logic between Visual Basic® Scripting Edition code
on the client and server objects. Automation objects
written in Visual Basic can expose services to client-side
applications, while protecting business logic and
data from distribution. Developers are no longer
restricted to choosing between "thin"
or "fat" clients and servers. They can
make an informed choice and partition their data
and business logic accordingly.
Object-oriented
database systems are quite different from the extremely
relational database systems (e.g., MS Access, FoxPro,
DBase, etc) that are extremely popular today.
I will begin this module with a quote from my favorite
online textbook in accounting information systems
(that I adopt each year for my ACCT 5342 course):
Emerging
database systems concepts
We conclude this chapter with a brief discussion
of an emerging concepts relating to database systems.
Object-oriented (OO) approaches to modeling and
implementing database systems are becoming increasingly
popular. This approach employs object-oriented modeling
(OOM) techniques to model the domain of interest
and then implements the resulting model using an
object-oriented database management system (OODBMS).
The object-oriented approach focuses on the objects
of interest in the domain. Customers, vendors, employees,
sales orders, and receipts are all viewed as objects
that have certain attributes. OOM involves identifying
the objects of interest, their attributes, and relationships
between objects.
A
critical feature unique to the OO approach is that
an "object" package includes both the
attributes of the object and the methods or procedures
that pertain to that object. The methods might dictate
how the object's attributes are modified in response
to different events, or how the object causes changes
in the attributes of other objects. Thus, a key
difference between the database models described
earlier and the OO approach is that OO models combine
data (attributes) and procedures (methods) in one
package, i.e., the "object." This feature
of OO models is referred to as encapsulation - attributes
and methods are represented together in one capsule.
Another powerful feature of OO models is inheritance.
OO models depict the real world as a hierarchy of
object classes, with lower level classes inheriting
attributes and methods from higher level classes.
Thus, lower level object classes do not need to
redefine attributes and methods that are common
to the higher level object classes in the class
hierarchy.
An
OO model contains all details needed for implementation
and object-oriented DBMS are powerful enough to
represent all the information contained in the model.
However, most organizations that have made heavy
investments in RDBMS see little need to migrate
to OO environments. While OO modeling methods are
available, there is no consensus regarding the "best"
method to use. Finally, although OODBMS are beginning
to become commercially available, they have not
gained much acceptance in the marketplace probably
due to their relatively high cost and poor performance
in comparison to RDBMS. Gemstone, ObjectStore, VBase,
and O2 are some examples of OODBMS.
Accounting
Information Systems: A Database Approach
by Uday S. Murthy and S. Michael Groomer
For more information go to http://www.cybertext.com/
Next
I will repeat a great illustration pointed out in
the message below from Alexander Lashenko:
Hello
Bob,
Take
a look at http://www.sanbase.com/cx.html
It's
an original object-oriented DBMS with web interface.
Looks very nice.
Regards,
Alex.
Alexander Lashenko [alashenko@cryptologic.com]
See
also Knowledge
Managment and Search
Engine.
For
non-hierarchical online database design see OLAP.
See
also Data Mining
See
CASE
See
Windows File System (WFS)
Database building from the WWW = (See Web surfing
backwards and OLAP)
Data Mining and Data Warehouse =
Data
Warehouse
A database, frequently
very large, that can access all of a company's information.
While the warehouse can be distributed over several
computers and may contain several databases and
information from numerous sources in a variety of
formats, it should be accessible through a server.
Thus, access to the warehouse is transparent to
the user, who can use simple commands to retrieve
and analyze all the information. The data warehouse
also contains data about how the warehouse is organized,
where the information can be found, and any connections
between data. Frequently used for decision support
within an organization, the data warehouse also
allows the organization to organize its data, coordinate
updates, and see relationships between information
gathered from different parts of the organization.
www.sellmorenow.com/gosfa/glossary.htm
Data
mining is the discovery and modeling of hidden patterns
in large amounts of data. It is usually case-based,
in that the parameters can be statistically modeled.
Technically, data mining is statistical analysis,
but on a complex scale. IBM invented data mining
and holds some of the patents. One of the goals
of data mining is to allow the user to discover
patterns and build models automatically, without
knowing exactly what she's looking for.
The
models are both descriptive and prospective. They
address why things happened and what is likely to
happen next. A user can pose "what-if"
questions to a data-mining model that can not be
queried directly from the database or warehouse.
Examples include: "What is the expected lifetime
value of every customer account," "Which
customers are likely to open a second account,"
or "Will this customer cancel our service if
we introduce higher fees?" (Questions like
this assume a Natural Language front end.)
Text
mining is a subset of data mining which applies
the same rules and logic, but is directed at gleaning
information from large bodies of text rather than
numerical data. The information technologies associated
with making data mining a functional process are
neural networks, genetic algorithms, fuzzy logic,
and rule induction. Data mining is becoming more
prevalent as businesses, governments and organizations
look for ways to leverage the existing mountains
of information they already have.
"Machines in the Myths: The State of Artificial
Intelligence," by DeAnne DeWitt, ChipCenter
--- http://www.chipcenter.com/columns/ddewitt/col002.html
DATATEL
= see database.
DAV= Digital
Audio Video connectors such as those
found on the Apple AV that allow the flow of digitized
video to bypass the computer's main bus. (See also
Bus)
DB 2
= see database.
dbx= The
"companding" compression and expansion
of audio signals to reduce noise distortions of
stereo television broadcasts. (See also MTS/SAP)
DCC= Digital
Compact Cassette format that improves
sound quality relative to traditional analog formats
of audio cassettes. Analog cassettes can be played
on DCC tape decks such that the purchase of a DCC
tape deck does not preclude listening to analog
tapes.
DCOM = (See
CORBA
)
Debugging= Executing
a program, one statement at a time, to identify
and fix errors.
DEC Alpha=
(See Alpha
processor)
Delta Project= A European Economic Community (EEC) funded project
of the Commission of European Communities. With
a budget of over $100 million, this is probably
the world's largest attempt to apply modern technologies
to distance training and education. Partners in
the project include major universities, telecommunications
companies, and business firms of all sizes across
the EEC. Collis
and de Vries (1994) report on 27
major projects with over 300 sub-projects in network
education and multimedia development.
Data Encryption Standard (DAS)=
The Data Encryption Standard, or DES, was the first
official U.S. government cipher intended for commercial
use. DES is the most widely used cryptosystem in
the world.
Also
see security.
Denial of Service Attacks --- http://www.trinity.edu/rjensen/ecommerce/000start.htm#DenialOfService
Desktop Search= Search utilities that
search for words, phrases, characters, pictures,
and even multimedia files on your personal computer.
Popular alternatives are from Google (GDS) , Yahoo,
and Microsoft --- http://www.trinity.edu/rjensen/searchh.htm#WebDesktop
See also OCR.
Device driver= Software that controls the communications
between a computer program and various hardware
devices such as the sound card, the video card,
the CD-ROM player, the MIDI, disk drives, etc.
DHTML
- (See HTML.)
Dial-up connection= The most
popular form of Net connection for the home user,
this is a connection from your computer to a host
computer over standard telephone lines.
Digital Video (DV) Camcorder= (See Video
camera and Video
from digital (DV) camcorders)
DIP Switch=
Dual In-line Package case on
a computer board that contains small switches for
configuring hardware components. A given board can
be configured in a way that is compatible with the
entire system of other peripheral hardware. (See
also Board)
Direct connection= A permanent
connection between your computer system and the
Internet. This is sometimes referred to as a leased-line
connection because the line is leased from the telephone
company.
DirectTV= (See DSS)
Disabilities products= A variety of hardware and software
options for users having certain types of disabilities.
The Trace R&D Center
(608-263-2309) at the University of Wisconsin-Madison
produces both a Trace Resource Book and a CD-ROM
that describes computer products for persons with
disabilities. An evaluation service is available
from the National Information System (800-922-9234,
Ext. 301), Center for Developmental Disabilities,
Benson Building, University of South Carolina, Columbia,
SC 29208. Mike Paciello has a good paper with links
at http://www.w3j.com/5/s3.paciello.html
. I also recommend that you use the search
term "disabilities" at http://www.cmptv.com/.
(See also Speech
recognition and Text reading)
Disk-at-once recording= Single-session
recording mode, where all the data to be included
on a disk is written in one pass. You must write
in this mode to have your CD mass-produced by a
stamping house. (See also CD-R)
Distributed Network Computing= Distributed Network Computing
where a network computer can perform computing functions
in another computer on the same network. In the
early days of the Internet, Telnet could be used
for remote computing. In modern times, the trend
is toward database access and computing among networked
computers.
Development
tools for data enabled frameworks are starting to
emerge. New standards are also starting to emerge
like CORBA's IIOP, Sun's RMI,
amd Microsoft's DCOM. RMI
is part of the Java programming language library
which enables a Java program running on one computer
to access the objects and methods of another Java
program running on a different computer. Some vendors
are also having their own proprietary extensions
as well. IIOP
is built upon CORBA
technology. DCOM
is Microsoft Corporation's standard for distrubuted
network computing. See Database,
ADO, and RDS .
A
good reference for more extensive distributed network
computing terminology is World Wide Web and Object Technology by
Ashish B. Shahhttp at
http://ei.cs.vt.edu/~wwwbtb/fall.96/book/chap19/index.html
Bob
Jensen's summary document entitled "Networked
Databases: Past, Present, and Future,"
can be found at
http://www.trinity.edu/rjensen/260wp/260wp.htm .
DLL = Dynamic
Link Library bundle of coded subroutines
that can be shared with different programs on the
system.
DNS= An acronym
for Domain Name Server, DNS
refers to a database of Internet names and addresses
which translates the names to the official Internet
Protocol numbers and vice versa.
Docking station= A platform that can be attached to portable
computers giving them a variety of added options
such as stereo speakers, a CD-ROM player, an SCSI
port, and bays for additional components such as
data tape drives and floppy disc drives. The numbers
and types of options vary among vendors. Some docking
stations are small and portable. Others are large
and relatively heavy, especially those docking stations
that provide notebook computers with added expansion
slots for boards such as video capture boards. Some
docking stations are reviewed in PC Computing, January
1995, p. 128. (See also Notebook
computer)
Document= When used
in reference to the World Wide Web, a document is
any file containing text, media or hyperlinks that
can be transferred from an HTTP server to a client
program.
Document Object Model
(DOM) = (See HTML)
Document type definition
= (See DTD.)
Document window= This is
the Web browser's scrollable window in which HTML
documents can be viewed.
Dolby-NR= Dolby-Noise Reduction system invented
by Ray Dolby. There are various levels of quality,
which in rank order from lowest to highest quality
include Dolby B (good), Dolby C (better), Dolby
S (best), and Dolby SR (professional). DSB Dolby
surround digital systems are even higher quality
systems used in movie soundtracks and videodiscs.
HDTV will also include DSD. A sound enforcement
system first used in the movie THX 1138 by
George Lucas is now known as the THX system. The
THX-licensed speakers use a professional Dolby process
for commercial and home theater systems. (See also
HX-Pro)
DOM = (See
HTML)
Domino = (see Lotus
Notes).
DOS= MS
DOS Microsoft Disk Operating
System introduced by Microsoft Corporation
in 1981. It became the operating system standard
for PCs around the world and still serves as the
foundation of the popular Microsoft Windows extended
operating system. The ability to operate from DOS
on low-capacity PCs having only 640K of random access
memory (RAM) has become the limitation in modern
times for DOS to remain a standard for higher speed
and higher RAM computers. DOS has not been upgraded
for newer 32-bit processors and will eventually
fade as the newer 32-bit, 64-bit, and higher capacity
PCs spread across world markets. (See also Operating
system, Windows,
Windows
Chicago, Windows
2000, and OS/2)
Download= To transfer
to your computer a copy of a file that resides on
another computer. For details see Modem.
Driver= A memory
resident program usually used to control a hardware
device.
Dry camera=
A digital camera that records images directly to
a disk or other medium that can be read directly
into computers without having to develop imaging
film with "wet" developer chemicals. Various
vendors have relatively inexpensive dry cameras
whereas these same vendors like Nikon, Kodak, Logitech,
and Dycam have superior and very expensive models
that have much higher imaging quality. Apple, Stormware,
and other vendors have only the lower priced modes.
Photographs can be scanned readers that plug into
the back PCs, although the later versions will also
plug directly into a PCMCIA slot for downloading
into a computer. An example of the latter option
is Nikon's Coolpix model. (See also Video
camera and Video
from digital (DV) camcorders)
DSD= (See
Dolby-NR)
DSL= Digital
Subscriber Line technology for transmitting data
up to 50 times faster than present analog modem
and ISDN alternatives. Telephone companies are hoping
that DSL service will keep telephone lines competitive
with cable modems and other competitive alternatives
to present telephone transmission services. Telephone
companies are considering two dominant DSL technologies:
Asymmetric Digital Subscriber Line (ADSL, ASL) and
High Rate Digital Subscriber Line (HDSL). ADSL technology
will deliver higher downstream speeds (6 Mbps) than
upstream speeds (640 kbps).
By
the way, ADSL or ASL differs from DSL in that there
is an asymmetry in transmission speeds into (download)
and out of (upload) your computer. In ASL,
the upload speeds are much slower than the download
speeds. However, ASL connections are being
pushed heavily into the huge home market, whereas
DLS is being touted for the business firm market.
For
additional information, seehttp://www.kentrox.com/news/110696.pr.html.
See also MMDS
and Modem.
Bob:
Below is something that might make a good entry
into your Technology Glossary. (Text below from
What is.com) Ever since I got a DSL line I have
been unable to log onto Temple University's primary
mail server. I receive an abrupt and annoying message
"The TCP/IP connection was unexpectedly terminated
by the server." It happens that Temple has
security procedure in place for this server that
traces my IP address back to my ISP to verify my
name when I try to log on to get my mail. However,
my ISP uses a newer system called "Reverse
Address Resolution Protocol" (RARP), which
does not keep a list of names on a name server for
immediate verification. (Maintaining an up-to-date
list of client names on a name server apparently
is an expensive, labor-intensive process.) I doubt
if my ISP is the only one using this technology.
This is an interesting clash of old fashioned security
procedures and newer technology.
Steve Fogg
Reverse
Address Resolution Protocol
RARP
(Reverse Address Resolution Protocol) is a protocol
by which a physical machine in a local area network
can request to learn its IP address from a gateway
server's Address Resolution Protocol (Address Resolution
Protocol) table or cache. A network administrator
creates a table in a local area network's gateway
router that maps the physical machine (or Media
Access Control - MAC address) addresses to corresponding
Internet Protocol addresses. When a new machine
is set up, its RARP client program requests from
the RARP server on the router to be sent its IP
address. Assuming that an entry has been set up
in the router table, the RARP server will return
the IP address to the machine which can store it
for future use. RARP is available for Ethernet,
Fiber Distributed-Data Interface, and token ring
LANs.
Stephen
L. Fogg, Ph.D., CPA,
Chair Department of Accounting Fox School of Business
and Management
Temple University Philadelphia, PA 19122 Phone:
215-204-1915 Fax: 215-204-5587 URL: http://www.sbm.temple.edu/~fogg
DSP= Digital
Signal Processing chips that are common
in cards (boards) added to expansion slots in computers,
especially for adding multimedia to computers. In
the future, DSPs and video hardware will probably
be more common on motherboards instead of add-on
boards. All major sound systems for PCs in the future
will probably be upgraded to DSP-based audio chips,
many of them right on the motherboard. (See also
Sound
board and Multimedia
Video Processor)
DSS= Digital
Satellite Systems such as those introduced
by Hughes Communications and USSB United States
Satellite Broadcasting, Inc. The term for commercial
satellite dishes used for this system is DirectTV
which will compete actively with full-service cable
TV. Since 120 channel capacity is expected on small
18-inch home satellite dishes, it becomes much more
feasible to bring remote education into homes, schools,
and offices. For a review of DSS, see Barcroft
(1993). (See also Teleconference)
DSU= The abbreviation
for Digital Services Unit,
DSU replaces the modem in synchronous connections
to the Internet.
DTD = Document Type Definition A document type definition
(DTD) that follows the rules of the Standard Generalized
Markup Language (SGML). A DTD is a specification
that accompanies a document and identifies what
the funny little codes (or markup) are that separate
paragraphs, identify topic headings, and so forth
and how each is to be processed. For example,
the most common DTD in web documents is HTML.
DTD is vital to extracting SGML and XML from
web documents and databases that are not marked
up with SGML or XML. See wrapper.
DTP = can stand for DeskTop Publishing
or Distributed Transaction Processing.
Anthony Frey on Network Computing Online, October
24, 1997 compares four middleware DTP monitors and
states the following at http://techweb.cmp.com/nc/820/820r1.html
If someone told you Microsoft
Windows 2000 is a better application server than
Novell NetWare or Unix, what kind of applications
would they be talking about? Microsoft Exchange
or Lotus Notes? No. Oracle? Not likely. A Web server?
Definitely not. In most cases these folks are refering
to distributed transaction processing (DTP) monitors.
When networking vendors claim "one billion
transactions per day" or quote Transaction
Processing Council TPC-C benchmark results, they're
talking about DTP.
These often-overlooked
middleware packages provide the essential communications
and other services that enable business logic to
be hosted on distributed servers in the middle tier.
This business logic is made up of real applications--applications
that are vital to most enterprise line-of-business
operations. DTP monitors ensure complete transactional
integrity for transactions between distributed relational
database management systems (RDBMSes). Perhaps more
than any other type of middleware, DTP monitors
have enabled true three-tier client/server computing.
See
also Database
and Middleware.
Dual Boot=
"Before Going to Buy High-Tech Devices, Learn the New Terms,"
by Walter S. Mossberg, The Wall Street Journal,
November 16, 2006; Page B1 --- http://online.wsj.com/article/personal_technology.html
Dual Boot: A computer that is configured to boot, or to start up,
in two different operating systems, depending on
which the user chooses at any one time. The most
important example of this currently is on Apple's
Macintosh computers, which now can be set up to
run either the Mac operating system or Microsoft
Windows using Apple's free dual-boot software, called
Boot Camp.
Dual Core=
Dual Core: A type of microprocessor -- the brain that runs a computer
-- which packs the equivalent of two processors
into a single chip. The best known dual-core processors
in consumer computers are Intel's Core 2 Duo and
Core Duo, but rival AMD also makes them. They are
a good bet for most people.
DVD= (See CD-DVD)
DVD-RAM= (See CD-DVD)
DVI= Digital
Video Interactive video compression
hardware and standard developed by the Moving Pictures
Experts Group (MPEG)
before MPEG
video boards hit the market. DVI is a form of compressed
full-motion video for computer file storage. Full-motion
video at over 30 frames per second takes up so much
digitized storage that video must be compressed
to make it more useful in hypermedia. DVI was an
early compression option that required special and
somewhat expensive DVI hardware installation inside
the computer of both authors and users (readers)
of hypermedia materials. New technology allows for
video compression without such expensive hardware.
MPEG hardware for video coded compression and decompression
seems to be taking over the recent market share
lead over DVI largely due to quality of the MPEG
and options emerging after DVI. At present, it is
not clear whether MPEG or DVI/Indeo will emerge
as the international standard with greatest market
acceptance. Many analysts are betting on MPEG at
the moment. (See also Video
for Windows, QuickTime,
Compression,
Video,
Indeo,
MCI,
Ultimedia
Video, and MPEG)
