The Universal Serial BusWritten by Stephen Bucaro
----------------------------------------------------------- Permission is granted for below article to forward, reprint, distribute, use for ezine, newsletter, website, offer as free bonus or part of a product for sale as long as no changes are made and byline, copyright, and resource box below is included. ----------------------------------------------------------- The Universal Serial Bus
By Stephen Bucaro
Ports are connectors provided on a computer to comunicate with peripheral devices such as modems and printers. The RS232 serial port introduced in 1969 could transfer data at a speed of 20 Kbps (kilobytes per second). The parallel port introduced in 1981 could transfer data at a speed of 150 Kbps. Later improvements increased speed of parallel port to 4 Mbps (megabits per second). Serial ports and parallel ports are frequently subject to resource conflicts.
In 1996 Universal Serial Bus (USB) was developed to replace serial and parallel ports. Today, USB port is used to connect scanners, digital cameras, and external storage devices like CD-RW drives. USB 1.1 can transfer data at a speed of 12 Mbps. USB 2.0, introduced in 2000, can transfer data at a speed of 480 Mbps.
Besides much higher speed, a main feature of USB is that you can plug and unplug devices without restarting computer. The controller will sense device and reconfigure. Installing a USB device is as simple as plugging it into a USB port.
Another feature of USB is that a single controller can support up to 127 devices simultaneously. A USB device can provide a port for another device, allowing you to "daisy chain" devices together, or you can use a stand alone hub. USB uses a single IRQ, I/O address range, and DMA controller to poll devices for data.
The USB cable has four wires, two for communications, and two that can provide up to 500 mA (milliamps) of power to USB devices. This means devices that only need a small amount of power don't need to have a separate power supply and power cord.
Specialized Solutions Unveils New CompTIA Server+ TrainingWritten by Cheryl Pelchat
Tarpon Springs, FL - Specialized Solutions, Inc., premier developer of self-study and certification training products, unveils its new CompTIA Server+ Certification Training and Test Preparation Course.
CompTIA Server+ Certification certifies competency of network administrators working in IT industry. In today's computer industry, it isn't enough to know an operating system to be a system administrator. The challenges of multi-platform support, changing user needs, increased server demand, maintenance, setting control, and disaster planning that meet network professionals require more than a casual reading of an operating system manual. The ability of computer networks to remain functional continuously has become dependant on server operators. Professionals who have Server+ training, who have demonstrated ability to respond to individual and organizational demands for computing resources by passing CompTIA Server+ certification exam, will be in demand in their companies. Administrators who have had instruction identifying and addressing causes of network problems before they affect organizational performance, can use real-world tools, and understand server infrastructures will demand respect of IT industry. Network administrators who successfully complete our complete Server+ training will not only pass CompTIA Server+ exam, but will also succeed in setting up and maintaining servers no matter what network operating system their organization chooses.
Dave Smith, vice president at CompuCom Systems Inc., confirmed value in Server+ certification: