THE WHATIS.COM WORD-OF-THE-DAY March 5, 2004 sonar
_____________ SPONSORED BY: PC Lifecycle Info Center Visit the new PC Lifecycle Info Center on SearchCIO.com. You'll find news, tips, webcasts, white papers and targeted Web resources focused on all aspects of managing the PC lifecycle - from purchase to retirement. Get valuable advice and insight on how your IT organization can make smart PC investment decisions. Topics covered include PC replacement cycles, patch management, ROI, mobile workforce management, desktop security, data backup, wireless LAN -- and much more! http://WhatIs.com/r/0,,25773,00.htm?track=NL-34&ad=477766&intel ______________________ TODAY'S WORD: sonar See our complete definition with hyperlinks at http://whatis.techtarget.com/definition/0,,sid9_gci953700,00.html?track=NL-34&ad=477766 Sonar is an acronym for sound detection and ranging. The principle involves bouncing acoustic waves off of objects, and determining their distances by measuring the time for the echoes to return. Sonar is commonly used on board ships and boats to measure the depths of bodies of water. It can also be used to locate underwater objects such as fish, submarines, and the shipwrecks of Spanish galleons. A complete sonar set has several components, including an acoustic pulse generator, a transducer for transmitting acoustic waves in narrow beams, an acoustic pickup, a set of amplifiers, a delay timer, and an indicating display. The distance to an object depends on the echo delay. For sonar to be accurate, the speed of sound in the medium must be known. Precision sonar equipment can rival machine vision for mapping and navigation purposes. A high-level sonar set can differentiate among objects in its vicinity. This ability to distinguish individual objects, also called targets, from one another is called the resolution. In order for a sonar set to have high resolution, the acoustic-wave beam must be narrow, and it must be swept around in two or three dimensions. _________________________ RELATED TERMS: speed of sound http://whatis.techtarget.com/definition/0,289893,sid9_gci832223,00.html?track=NL-34&ad=477766 ______________________ SELECTED LINKS: Humminbird shows how sonar is used to locate fish. http://www.humminbird.com/hb_ProductSupport.asp?id=99 ______________________ WEBCAST | Application-layer firewalling: Raise your perimeter IQ Traditional perimeter firewalls perform Layer 3 and 4 port and protocol filtering, stateful inspection, NAT and VPN. Now, firewall vendors are introducing new technologies to perform application-layer filtering in both proxy and stateful configurations. Join us on March 10 at Noon ET as Joel Snyder, senior partner with consulting firm Opus One, uncovers the hype versus reality of application-layer firewalling. Joel will explore issues such as cost/benefit, technology maturity, configuration and administration challenges, and integration with existing intra-LAN security devices. >> Pre-register for this live webcast on March 10 at Noon ET http://searchsecurity.com/firewall2?track=NL-34&ad=477766 ______________________ TODAY'S TECH NEWS: EXPERTS SEE IM AS FOUNDATION FOR NEW-AGE APPS Experts at the Instant Messaging Planet Conference & Expo said that, in the absence of an IM strategy, "stealth" IM use could have dangerous consequences in the enterprise. http://searchnetworking.techtarget.com/originalContent/0,289142,sid7_gci953583,00.html?track=NL-34&ad=477766 FACE-OFF: ORACLE VS. SQL SERVER Two site editors square off on the topic of SQL Server versus Oracle, a debate with equally loud fans on either side of the issue. http://searchdatabase.techtarget.com/originalContent/0,289142,sid13_gci953120,00.html?track=NL-34&ad=477766 SOFTWARE UPGRADE COSTS IRK MAINFRAME USERS Users laughed at a recent Search390.com article on the cost incentives of upgrading the mainframe. The joke? Hardware is cheap. It's the software upgrades that are killing users -- and forcing many onto other platforms. http://search390.techtarget.com/originalContent/0,289142,sid10_gci953638,00.html?track=NL-34&ad=477766 >> Catch up on all the latest IT news at http://searchtechtarget.techtarget.com?track=NL-34&ad=477766 ______________________ SECRET WORD-OF-THE-DAY | What is IT? In science fiction, this might be an entranceway to an alternate universe. On the Internet, however, it's a Web site that serves as a starting site for users or one that they tend to visit as an anchor site. Do you think you know the Secret Word? Click to see if you're right! http://searchcio.techtarget.com/gDefinition/0,294236,sid19_gci212810,00.html?track=NL-34&ad=477766 ______________________ FAST REFERENCE | How many bytes for... (NEW!) How many bytes would it take to store the print collections of the U.S. Library of Congress? Our newest Fast Reference provides tables and other information about how many bytes are required (how much computer storage) for various information objects or purposes. http://searchstorage.techtarget.com/sDefinition/0,,sid5_gci944596,00.html?track=NL-34&ad=477766 ______________________ HOROSCOPES FOR GEEKS | March Find out what the stars have in store for you this month! http://searchcio.techtarget.com/sDefinition/0,,sid19_gci919205,00.html?track=NL-34&ad=477766 ______________________ LEARN IT | Software development Here's how it works: We give you a little background about the concept, a glossary to look up related terms, some outside reading, and a self-assessment quiz. You spend as much (or as little) time as you like moving through the ten steps and exploring the concept. http://searchwin2000.techtarget.com/sDefinition/0,,sid1_gci936454,00.html?track=NL-34&ad=477766 ______________________________ RECENT ADDITIONS AND UPDATES [1] spim http://searchcio.techtarget.com/sDefinition/0,,sid19_gci952820_top1,00.html?track=NL-34&ad=477766 [2] bluesnarfing http://searchmobilecomputing.techtarget.com/sDefinition/0,,sid40_gci952393,00.html?track=NL-34&ad=477766 [3] vulnerability disclosure http://searchcio.techtarget.com/sDefinition/0,,sid19_gci952151,00.html?track=NL-34&ad=477766 [4] GMPLS http://searchnetworking.techtarget.com/sDefinition/0,,sid7_gci950984,00.html?track=NL-34&ad=477766 [5] Power over Ethernet http://searchnetworking.techtarget.com/sDefinition/0,,sid7_gci846792,00.html?track=NL-34&ad=477766 ____________________________________________________________________ ::::::::::::::::::: WHATIS.COM CONTACTS ::::::::::::::::::: MARGARET ROUSE, Site Editor ([EMAIL PROTECTED]) IVY WIGMORE, Consulting Editor ([EMAIL PROTECTED]) LOWELL THING, Consulting Editor and Founder ([EMAIL PROTECTED]) GABRIELLE DERUSSY, Advertising ([EMAIL PROTECTED]) ::::::::::::::::::::: ABOUT THIS NEWSLETTER :::::::::::::::::::::: This e-newsletter is published by WhatIs.com, a targeted Web site from TechTarget, the most targeted IT media and events company. 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