Sunday, November 28, 2010

Earth Simulator

The Earth Simulator (ES), developed by the Japanese government's initiative "Earth Simulator Project", was a highly parallel vector supercomputer system for running global climate models to evaluate the effects of global warming and problems in solid earth geophysics. The system was developed for Japan Aerospace Exploration Agency, Japan Atomic Energy Research Institute, and Japan Marine Science and Technology Center in 1997. Construction started in October 1999, and the site officially opened on March 11, 2002. The project cost 60 billion yen.

Built by NEC, ES was based on their SX-6 architecture. It consisted of 640 nodes with eight vector processors and 16 gibibytes of computer memory at each node, for a total of 5120 processors and 10 terabytes of memory. Two nodes were installed per 1 metre x 1.4 metre x 2 metre cabinet. Each cabinet consumed 20 kW of power. The system had 700 terabytes of disk storage (450 for the system and 250 for the users) and 1.6 petabytes of mass storage in tape drives. It was able to run holistic simulations of global climate in both the atmosphere and the oceans down to a resolution of 10 km. Its performance on the LINPACK benchmark was 35.86 TFLOPS, which was almost five times faster than ASCI White.

Reference material

M-Commerce

Mobile Commerce, also known as M-Commerce or mCommerce, is the ability to conduct commerce using a mobile device, such as a mobile phone, a Personal digital assistantPDA, a smartphone, or other emerging mobile equipment such as dashtop mobile devices. Mobile Commerce has been defined as follows:

"Mobile Commerce is any transaction, involving the transfer of ownership or rights to use goods and services, which is initiated and/or completed by using mobile access to computer-mediated networks with the help of an electronic device."

Mobile commerce was born in 1997 when the first two mobile-phone enabled Coca Cola vending machines were installed in the Helsinki area in Finland. The machines accepted payment via SMS text messages. The first mobile phone-based banking service was launched in 1997 by Merita Bank of Finland, also using SMS.

In 1998, the first sales of digital content as downloads to mobile phones were made possible when the first commercial downloadable ringtones were launched in Finland by Radiolinja (now part of Elisa Oyj).

Two major national commercial platforms for mobile commerce were launched in 1999: Smart Money (http://smart.com.ph/money/) in the Philippines, and NTT DoCoMo's i-Mode Internet service in Japan. i-Mode offered a revolutionary revenue-sharing plan where NTT DoCoMo kept 9 percent of the fee users paid for content, and returned 91 percent to the content owner.

For reference

Socket Programming

Sockets are interfaces that can "plug into" each other over a network. Once so "plugged in", the programs so connected communicate. A "server" program is exposed via a socket connected to a certain /etc/services port number. A "client" program can then connect its own socket to the server's socket, at which time the client program's writes to the socket are read as stdin to the server program, and stdout from the server program are read from the client's socket reads.

Before a user process can perform I/O operations, it calls Open to specify and obtain permissions for the file or device to be used. Once an object has been opened, the user process makes one or more calls to Read or Write data. Read reads data from the object and transfers it to the user process, while Write transfers data from the user process to the object. After all transfer operations are complete, the user process calls Close to inform the operating system that it has finished using that object.

 

For Reference