Sunday, May 27, 2007

Motorola

Most of Motorola's products have been radio-related, starting with a battery eliminator for radios, through the first walkie-talkie in the world, defense electronics, cellular infrastructure apparatus, and mobile phone manufacturing. The company was also strong in semiconductor technology, including integrated circuits used in computers. Motorola has been the main supplier for the microprocessors used in Commodore Amiga, Apple Macintosh and Power Macintosh personal computers. The chip used in the latter computers, the PowerPC family, was developed with IBM and in a partnership with Apple. Motorola also has a diverse line of communication products, including satellite systems, digital cable boxes and modems.

Friday, May 18, 2007

Battery isolator

A battery isolator is a one-way electrical valve, allowing DC current to flow in one direction, but not flow in reverse. They are commonly used on vehicles where multiple batteries or battery banks are used, including recreational vehicles, boats, utility vehicles, airplanes, and large trucks. The primary purpose for their use is to insure that a failure of a single battery or battery bank, will not wipe out an entire battery network.

Several technologies have been used to achieve control of DC current in this manner: silicon rectifier packages, Schotkey rectifier packages, MOSFET rectifier packages, and conventional mechanical relays.

Sunday, May 13, 2007

Purposes of worms

Many early communicable programs, including the Internet Worm and a number of MS-DOS viruses, were written as experiments or mischief generally intended to be harmless or merely annoying rather than to cause serious damage. Young programmers learning about viruses and the techniques used to write them might write one to prove that they can do it, or to see how far it could spread. As late as 1999, extensive viruses such as the Melissa virus appear to have been written chiefly as pranks.

A slightly more antagonistic intent can be found in programs designed to vandalize or cause data loss. Many DOS viruses, and the Windows Explore Zip worm, were designed to destroy files on a hard disk, or to corrupt the file system by writing junk data. Network-borne worms such as the 2001 Code Red worm or the Ramen worm fall into the same group. Designed to vandalize web pages, these worms may seem like the online equivalent to graffiti tagging, with the author's alias or similarity group appearing everywhere the worm goes.

Wednesday, May 09, 2007

Mod chip

Xenium Mod Chip attached to an Xbox. The 2x6 header interfaces the chip with the LPC bus, while the red soldered wire overrides the original BIOS's D0 line. A Mod chip, a portmanteau of 'Modification microchip', is a device used to get around the digital rights management of many popular game consoles, including those made by Microsoft, Sony, and Nintendo for the purposes of playing backup, imported, pirated, or homebrew games and/or applications. They are used mostly on systems that are CD/DVD-based due to the availability and low cost of blank media such as CD-R s and DVD+/-R s.

Almost all modern console gaming systems have hardware-based schemes which ensure that only officially authorized games may be used with the system and implement regional lockout similar to the scheme used in DVD movies. The specific technical nature of these DRM systems varies by system, and may include cryptographic signing, intentionally unreadable sectors, custom optical media, or some combination thereof. Mod chips are available also for some DVD players, to defeat region code enforcement and user.

Tuesday, May 01, 2007

Robotics

Robotics is the science and technology of robots, their design, manufacture, and application.Robotics requires a functioning knowledge of electronics, mechanics, and software. A person working in the field is a roboticist. The word robotics was first used in publish by Isaac Asimov, in his science fiction short story "Runaround" (1941).

Although the exterior and capabilities of robots fluctuate enormously, all robots share the features of a mechanical, movable structure under some form of control. The chain is warped of links ,actuators and joints which can allow one or more degrees of freedom. Most contemporary robots use open serial chains in which each link connects the one before to the one after it. These robots are called serial robots and often resemble the human arm. A few robots, such as the Stewart platform, exploit closed parallel kinematic chains. Other structures, such as those that mimic the mechanical structure of humans, different animals and insects, are comparatively rare. However, the development and use of such structures in robots is an dynamic area of research. Robots used as manipulators have an end effector mounted on the last link. This end effector can be anything from a welding mechanism to a mechanical hand used to manipulate the environment.