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Terms for computer junkies
PUMP up your computer-related vocabulary! Load your brains with these frequenty used i-terms.
Metadata: Data about data. Metadata describes how and when and by whom a particular set of data was collected, and how the data is formatted. Metadata is essential for understanding information stored in data warehouses.
Near-line storage: Near-line storage is used by data warehouses as an inexpensive, scalable way to store large volumes of data. Near-line storage devices include DAT and DLT tapes (sequential access), CD-ROMs, DVD-ROMs DVD-RAMs and Magneto-Optical (random access) devices. Retrieval of data can be slow, but the type of data dictates that the information will not be accessed often.
Dynamic DNS: Short for dynamic Domain Name System, a method of keeping a domain name linked to a changing IP address as not all computers use static IP addresses. When a user connects to the internet, the user’s ISP assigns an unused IP address from a pool of IP addresses, and this address is used only for the duration of that specific connection. This method extends the usable pool of available IP addresses.
A dynamic DNS service provider uses a special program that runs on the user’s computer, contacting the DNS service each time the IP address provided by the ISP changes and subsequently updating the DNS database to reflect the change in IP address.
Static: Generally refers to elements of the internet or computer programming that are fixed and not capable of action or change. The opposite of static is dynamic.
A static website can only supply information that is written into the HTML and this information will not change unless the change is written into the source code. When a web browser requests the specific static web page, a server returns the page to the browser and the user only gets whatever information is contained in the HTML code.
IP Multicast: Sending out data to distributed servers on the MBone (Multicast Backbone). For large amounts of data, IP Multicast is more efficient than normal Internet transmissions because the server can broadcast a message to many recipients simultaneously. Unlike traditional Internet traffic that requires separate connections for each source-destination pair, IP Multicasting allows many recipients to share the same source. This means that just one set of packets is transmitted for all the destinations.
Narrowcast: To send data to a specific list of recipients. Cable television is an example of narrowcasting since the cable TV signals are sent only to homes that have subscribed to the cable service. In contrast, network TV uses a broadcast model in which the signals are transmitted everywhere and anyone with an antenna can receive them.
The internet uses both a broadcast and a narrowcast model. Most Web sites use a broadcast model since anyone with internet access can view the sites. However, sites that require you to log-in before viewing content are based more on the narrowcast model. The various push technologies are another form for narrowcasting. Perhaps the best example of narrowcasting are e-mail lists where messages are sent only to individuals who subscribe to the list.
The terms multicast and narrowcast are often used interchangeably, although narrowcast usually refers to the business model whereas multicast refers to the actual technology used to transmit the data.
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