20 April 2006

Hosting a Website

In order for a website to be available for public access, it has to be hosted on a computer that is continuously connected to the Internet. What this means is that the data files are stored on a computer that is configured to deliver them when requested. Such computers are known as web hosts, and they require several special features.

A person who wants to set up a website needs to have a web host. Usually the company that provides her with internet access (her ISP) will over some limited web hosting services as part of the overall package. However, if the website will have a lot of big data files, such as image files, audio files, and CGI applications, then the prospective webmaster will probably want an account with a dedicated hosting service.
Requirements of a Web Host

First among these is, as mentioned, continuous network access. Since internet access to the website may vary dramatically over time, the bandwidth of this connection must be considerable. Usually, this involves a T-carrier system (T1) connection for handling massive volumes of digital information over a variety of different types of cable. Internet service providers (ISPs) use T-carrier systems to provide large numbers of files to large numbers of requesters (i.e., web browsers) at a time.

Second, the computer requires FTP software. FTP (file transfer protocol) is a universally-recognized system for transferring all types of data over the internet. The host—AKA an FTP server—listens on the network for connection requests from other computers. When someone surfing the web connects to a website, that person's browser—AKA an FTP client—initiates a connection to the host computer. Once connected, the client can upload data files to the server, download files from the server, rename or delete files on the server and so on.

Thirdly, the web hosting service will require several programs required for managing web-delivered applications. An example of a web-delivered application is an e-commerce website, such as Amazon. In addition to having a standardized web page for each product (which is created or updated merely by a vendor inputing product information to a form), Amazon's website allows users to enter payment and shipping information, then generates a bill for them.

A far more modest example is a content management system, such as a blogging software. One of the more popular of these is Movable Type, which the user installs on her own host. Movable Type is an example of a common gateway interface (CGI) application. CGI is a specific protocol that requires the server to launch a program whenever the client inputs data. The program outputs data and sends the output to the client's web browser as web page. This requires a fresh copy of the program to be executed for every CGI request, so the script interpreters have to be integrated directly into web servers as modules.

This is the purpose of the CGI bin, a folder with unique permissions located in the root of the hosted account. CGI applications are now extremely common on the web for non-commercial users. For those with e-commerce accounts or massive, business-oriented databases, much more advanced capabilities are required.
SOURCES & ADDITIONAL READING: "Hosting," "File Transfer Protocol," "T-carrier system," SearchNetworking.com; "Web hosting service," "File Transfer Protocol,""Common Gateway Interface," Wikipedia;

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11 April 2006

Industrial Applications for Wi-Fi

Periodically I wonder about the ways in which small computing devices like the PDA can be used on the job; specifically, I'm interested in the application of these technologies in the implementation of efficiency methodologies like Six Sigma, Lean Production, and so on. One important feature is the application of Bluetooth and Wi-Fi to different production stations. Another would be RFID inventory management.

From a promotional In-Stat email:
SCOTTSDALE, Ariz., April 3, 2006 – Wi-Fi is increasingly being utilized in
location tracking applications, and Wi-Fi asset tags are expected to reach
almost 2 million shipments in 2010, reports In-Stat. The Wi-Fi location tracking market is still nascent, and many highly changeable factors will decide how fast it grows over the next few years, the high-tech market research firm says. Wi-Fi tags are utilized in Wi-Fi Real-Time Location Systems (RTLS) that utilize Wi-Fi access points (APs) to locate devices with external Wi-Fi tags or devices with embedded Wi-Fi.

"Wi-Fi- based RTLS provides the two-fold advantage of being able to 1. leverage standard Wi-Fi infrastructure for location tracking (instead of having to purchase standalone location reader devices), and 2. track any devices with embedded Wi-Fi, including laptops, scanners, phones, etc., right along with those assets with Wi-Fi tags," says Gemma Tedesco, In-Stat analyst. "So far, Wi-Fi RTLS has gained the most traction in healthcare, where Wi-Fi infrastructure has already been deployed on a relatively large scale, and where there exists many valuable assets to track, such as patient monitoring devices and wheelchairs."
The rest of the message addresses winners in industrial service appliacations, like WhereNet: this firm offers complex "real-time location systems" (RTLS).

Also on the subject, another study from In-Stat:
SCOTTSDALE, Ariz., March 8, 2006 – RFID technology has arrived in China in an unprecedented manner, with over 100 million tags shipped in 2005, and more than 2.9 billion tags forecast to be shipped by 2009, reports In-Stat. From 2005 through 2009, a major RFID application will be for human ID through China's second-generation Resident ID Card program, the high-tech market research firm says.

"With a population of over 1.3 billion, the issuance of RFID-tag-inlaid Resident ID cards by the Ministry of Public Security is one of the biggest RFID projects in the world," says Anty Zheng, In-Stat analyst. "More than one billion ID Cards will be issued before the end of 2008."
I find this fairly disturbing, that China's elites have decided to make such a huge investment in tracking the location of its citizens with RFIDs. Please note the vast majority of Chinese live under conditions of destitution and technical backwardness associated with the 19th century.

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