document type definition (DTD)

DTD is short for document type definition. The DTD states what tags and attributes are used to describe content in an SGML, XML or HTML document, where each tag is allowed, and which tags can appear within other tags.

Example of Document Type Definition

For example, in a DTD one could say that LIST tags can contain ITEM tags, but ITEM tags cannot contain LIST tags. In some editors, when authors are inputting information, they can place tags only where the DTD allows. This ensures that all the documentation is formatted the same way. Applications will use a document’s DTD to properly read and display a document’s contents. Changes in the format of the document can be easily made by modifying the DTD.

(Thanks to technical writer Ryan Mauldin for help in updating this definition.)

OMG IDL

Short for The Object Management Group (OMG) Interface Definition Language (IDL) it is used to describe the interfaces that client objects call and that object implementations provide. An OMG IDL interface definition fully specifies each operation’s parameters and provides the information needed to develop client applications that use the interface’s operations. [Source: OMG IDL Syntax]

HDMI – High-Definition Multimedia Interface

Short for High-Definition Multimedia Interface, it is the first industry-supported uncompressed, all-digital audio/video proprietary interface. It is a single cable and user-friendly connector that replaces the maze of cabling behind the home entertainment center. An HDMI cable provides an interface between any audio/video source, such as a set-top box, DVD player, or A/V receiver and an audio and/or video monitor, such as a digital television (DTV), over a single cable. HDMI supports standard, enhanced, or high-definition video, plus multi-channel digital audio on a single cable. It transmits all ATSC HDTV standards and supports 8-channel digital audio with bandwidth to spare to accommodate future enhancements and requirements. [Source: Adapted from HDMI.org, Nov 2005]

HDMI was defined to carry 8 channels, of 192kHz, 24-bit uncompressed audio, which exceeds all current consumer media formats. In addition, HDMI can carry any flavor of compressed audio format such as Dolby or DTS. HDMI has the capacity to support existing high-definition video formats such as 720p, 1080i, and 1080p, along with  support of enhanced definition formats like 480p, as well as standard definition formats such as NTSC or PAL. Since the original release of HDMI in 2002 there have been several HDMI versions however all use the same cable and connector.

HDMI Founders and Licensed Adopters

HDMI was developed by Developed by Sony, Hitachi, Thomson (RCA), Philips, Matsushita (Panasonic), Toshiba and Silicon Image. The 7 HDMI founders began development on HDMI 1.0 in 2002. The HDMI specification is not an open technology standard. This means manufacturers need to be licensed by HDMI LLC in order to implement HDMI in any product or component. Companies who are licensed by HDMI LLC are known as HDMI Adopters. Adopters have access to the latest HDMI standards, while earlier versions of HDMI specifications are available to the public for download. HDMI development is overseen by the HDMI Working Group.

Java IDL

Java IDL adds CORBA (Common Object Request Broker Architecture) capability to the Java platform, providing standards-based interoperability and connectivity. Java IDL enables distributed Web-enabled Java applications to transparently invoke operations on remote network services using the industry standard OMG IDL (Object Management Group Interface Definition Language) and IIOP (Internet Inter-ORB Protocol).

SDTV

Short for Standard Definition Television it is a type of digital television operation method which is able to transmit and produce images which are of a higher quality than standard analog broadcast. SDTV is typically a 480i signal – where 480 represents the vertical resolution and i represents interlaced. Digital cable and digital satellite programming is widely available in SDTV format. While SDTV does not reach near the quality of HDTV, it is superior over traditional analog television.

* SDTV Minimum Performance Attributes:

• Receiver: Receives ATSC terrestrial digital transmissions and decodes all ATSC Table 3 video formats, and produces a useable picture
• Display Scanning Format: Has active vertical scanning lines less than that of EDTV
• Aspect Ratio: None specified
• Audio: Receives and reproduces usable audio

(* Adapted from Digital Connection)

DDL

Short for Data Definition Language, DDL is a computer language that is used to define data structures. In Database Management Systems (DBMS), it is used to specify a database scheme as a set of definitions (expressed in DDL). In SQL, the Data Definition Language (DDL) allows you to create, alter, and destroy database objects.