Plextor University - USB 1.1 and USB 2.0 History USB stands for Universal Serial Bus. USB is a plug-and-play interface used between computers and add-on devices (such as audio players, joysticks, keyboards, scanners, mass storage devices, and printers). With USB, a new device can be installed into your computer without having to add an adapter card, or even having to turn the computer off. USB CD-RW drives can be installed by simply plugging them into the computer at any time during operation. The USB peripheral bus standard was jointly developed by Compaq, IBM, DEC, Intel, Microsoft, NEC, and Northern Telecom. The first computers that began shipping with USB capability, began showing up in late 1996. Today, the technology is now openly available for all computer and device vendors. Currently, USB is available on over 90% of computers manufactured today. Why USB? The purpose for USB was to provide a universal interface that would eventually replace different types of peripheral interfaces (parallel ports, serial ports, PS/2, etc.), while maintaining wide compatibly with current and future Windows operating systems. Since late 1996, Windows operating systems have been equipped with USB drivers or special software designed to work with specific USB I/O devices complying with the USB 1.0 Standard. With the introduction of Windows 98, a newer USB 1.1 standard was, for the first time, completely integrated within the operating system. The newer USB 1.1 Standard provided for tighter integration with Microsoft's Plug and Play standard (PnP), making installation of external devices and peripherals virtually hassle-free, while still maintaining backward-compatibility with existing USB 1.0 devices. USB has since been integrated into every Windows operating system, with the exception of Windows NT. USB Today Today, most new computers and peripheral devices are equipped with USB capability. The USB 1.1 Standard's integration into the Windows 98 operating system was the catalyst that allowed countless USB devices to be created and sold for use with personal computers. USB has slowly become the interface of choice for connecting such devices as keyboards, mice, scanners, printers, etc. However, newer and more-bandwidth-demanding devices such as digital cameras and external mass storage devices began to demonstrate the limitations of the USB 1.1 Standard. In late 2001, the USB 2.0 Standard was introduced to bridge the performance gap between the USB 1.1 Standard and the demand of high-bandwidth devices, while still maintaining wide compatibility with the current USB 1.1 Standard. USB 2.0 is over 40 times faster than USB 1.1, with data throughput speeds reaching up to 480Mbits/s. The chart below compares USB 2.0 performance with existing USB 1.1 performance, as well as other interface standards.   USB 1.1 USB 2.0 Parallel Port (ECP/EPP) Serial Port IEEE-1394 Firewire Max. Data Transfer Speed 12Mbits/s (1.5MBytes/s) 480Mbits/s (60MBytes/s) 24Mbits/s (3MBytes/s) 115kbits/s (0.115Mbits/s) 100-400Mbits/s (12.5-50MBytes/s) Plextor and USB? Plextor has recognized the immediate benefits of the USB 2.0 interface in relationship to its customer needs. Therefore, Plextor is now offering exciting new USB 2.0 drives, in addition to maintaining our existing line of high quality ATAPI and SCSI products.