&
Advertise Here with Today.com
 

Archive for the 'science' Category

Mar 24 2008

What’s WiMAX?

Published by ra7d_si2gar under info, network, science Edit This

WiMAX is a short name for Worldwide Interoperability of Microwave Access. WiMAX is described in IEEE 802.16 Wireless Metropolitan Area Network (MAN) standard. It is expected that WiMAX compliant systems will provide fixed wireless alternative to conventional DSL and Cable Internet.

Typically, a WiMAX system consists of two parts:

  • A WiMAX Base Station: Base station consists of indoor electronics and a WiMAX tower. Typically, a base station can cover up to 10 km radius (Theoretically, a base station can cover up to 50 kilo meter radius or 30 miles, however practical considerations limit it to about 10 km or 6 miles). Any wireless node within the coverage area would be able to access the Internet.
  • A WiMAX receiver - The receiver and antenna could be a stand-alone box or a PCMCIA card that sits in your laptop or computer. Access to WiMAX base station is similar to accessing a Wireless Access Point in a WiFi network, but the coverage is more.

Several base stations can be connected with one another by use of high-speed backhaul microwave links. This would allow for roaming by a WiMAX subscriber from one base station to another base station area, similar to roaming enabled by Cellular phone companies.

Important Wireless MAN IEEE 802.16 (WiMAX) Specifications 

Range - 30-mile (50-km) radius from base stationSpeed - Up to 70 megabits per secondNon-Line-of-sight (NLoS) between user and base stationFrequency bands - 2 to 11 GHz and 10 to 66 GHz (licensed and unlicensed bands)Defines both the MAC and PHY layers and allows multiple PHY-layer specifications. 
Advertise Here with Today.com

One response so far

Oct 08 2007

Playstation 3 New Face

Published by ra7d_si2gar under Hardware, science Edit This


Introduction

Lagging a full year behind the release of Microsoft’s Xbox 360 and lacking the immediately attention-grabbing hook of Nintendo’s 360-degree motion-sensing Wii, Sony’s long-awaited PlayStation 3 has recently been the subject of much heated debate. Despite its obvious appeal to diehard gamers and fans of the world’s most popular console brand – not to mention home theater enthusiasts, what with 1080p HDMI output and extensive online music/video download capabilities – questions have been plentiful.

For example: Is the system, available in 20GB ($499, sans WiFi and a built-in combination Memory Stick product lineup, Compact Flash and SD/MMC card reader) or $599 chrome-trimmed wireless-ready 60GB hard drive models, worth the hefty asking price, the highest since early-’90s systems like CDi and 3DO? Can Sony, who’s recently cut back North American November 17th launch date ship projections to just 400,000 units (with some analysts predicting actual distribution of half this number or fewer machines), manage to avoid aggravating a soon-to-be-device-deprived buying public while still keeping up with the competition? And, of course, with so much power and hardware combined in a single unit catered to the highest-end luxury users, is there even a point to upgrading?

The short answer to all: Yes, depending which of school of thought you fall into, your game playing habits and how much disposable income you’ve got to burn. However, let’s get one thing out of the way up-front, before you freeze your poor behind off spending all night camped out in front of the local electronics retailer hoping to score one of the severely under-stocked devices. For a host of reasons ranging from technical niggles to launch lineup shortfalls to pure common sense, it’s perfectly fine – and in most cases, even advisable – to skip buying one this holiday season and wait until the dust settles sometime early in 2007.

Right from the get-go, it’s important to consider the following fact: You’re not actually buying a videogame console here (although surely, that’s the machine’s strength and the chief function most prospective buyers intend to employ it towards) so much as a full-fledged digital media hub. As slick as everything from cutting-edge digital diversions and Blu-ray movies – video resolutions ranging all the way from 480i up to an eye-popping 1080p are supported – it’s what you personally make of the machine that gives the gizmo its true value. So for all of you who’ve been pestered since, oh, 2004 by your wide-eyed little pride and joys, remember: Dropping $599 just so kids can use the beast as an overgrown Atari may be a little much. They’ll be just as entertained by lower-resolution outings for other systems like Nintendo’s Wii or Sony’s own PlayStation 2. And, in truth, most PlayStation 3 titles right now are simply enhanced ports of existing products anyway (see offerings like Tony Hawk’s Project 8 or NHL 2K7). What’s more, unless you plan on clocking in time behind the controller yourself, investing in a library of next-generation movies, browsing the Web on your TV, purchasing extra levels/cars/characters/songs/films online or are intent on building the ultimate technophile’s living room setup, it’s the sort of holiday gift that may be little extravagant for anyone younger than 15.

No responses yet

Jul 25 2007

White screen of death

n Windows 95, Windows 98, Windows Me, Windows 2000, and (possibly) also Windows NT, a White Box of Doom or White screen of death will appear if an error occurs while loading a system-critical application or process, such as the system shell (e.g. Explorer.exe). It has a similar appearance to a General Protection Fault, or GPF.

Clicking “OK” will normally cause the computer to shut down, or it may result in another similar error. This error may also appear if, at startup, an illegal operation occurs during the startup process. Also it will make your computer freeze and you have to shut the computer down.

Some computers, such as Dell computers, have boot errors that result in a WSOD

Some computers, such as Dell computers, have boot errors that result in a WSOD

This error may occasionally be ignored, as it may just have been a single occurrence of a failed startup sequence; however, if it should occur repeatedly, the user may then be required to reinstall Windows.

A way to work around this if you don’t want to install Windows is to set the shell to Winfile.exe.

No responses yet

Next »

Advertise Here