HP NetServer LXr Pro8 Server Controllers and Mass Storage Devices - Page 9

ZKLWHýSDSHU +3ý 1HW6HUYHUý $FFHVVRULHV different levels (0, 1, 3, 5, 10, 30 and 50) which allow users to vary the degrees of performance, availability and flexibility. I2O The I2O (Intelligent Input/Output) specification defines an architecture for intelligent I/O that is independent of both the specified device being controlled and the host operating system (OS). The I2O specification has been developed to address two key problem areas in I/O processing: • System performance degradation caused by I/O interrupts to the CPU (the CPU is not doing data processing when it is processing I/O requests) • The necessity to create, test, and support unique drivers for every combination of I/O device and OS on the market HP was the founding company of the Special Interest Group (I2O SIG) and has had a significant input into the direction of the development effort of the specifications, including the initial invention, and has been assigned the patent. The new architecture of I2O utilizes an approach whereby I/O processors are used to handle I/O rather than the CPU which offloads low-level interrupts to these processors. The I2O specification also creates a "split driver" model so that the software drivers are portable across multiple OSs and host platforms. One portion of the driver runs in the operating system, the other portion runs in a separate I/O system. The split driver concept will reduce the number of drivers that must be written. OS vendors will write a single I2O-ready driver for each class of device-such as a disk drive-and the device manufacturers write a single I2O-ready driver for each device, which will work for any OS that supports I2O. The split-driver approach will drive down the cost of software development and support for I/O devices while increasing their availability across the range of operating systems. Other benefits that will come as I2O is fully implemented are improved server efficiency, reduced CPU utilization, "plug-and-play" flexibility, and a more stable I/O driver platform. I2O is being implemented step-by-step like many technology standards that came before it. Operating system vendors began releasing the systems that provide support for I2O in early 1998. Hewlett-Packard has launched the HP NetRAID-3Si disk array controller, the first in a line of HP NetServer products that will support the I2O standard. Fibre Channel Just as I2O capability improves the input/output transfers and the performance of the entire server system, the addition of Fibre Channel connectivity enhances system performance and availability. Fibre Channel was first offered with HP-UX server storage and has become widely available with NT-based servers over the last year. There are currently 3 external disk storage products that can be connected to HP NetServers via Fibre Channel-the HP Rack Storage/12FC, the HP Model 30/FC and the EMC Symmetrix. HP also offers connectivity of DLT Backup Libraries to FC via the HP SureStore Fibre Channel SCSI Bridge. Fibre Channel connections between server and storage are made using a set of components similar to those used for IP networking. A Fibre Channel-to-PCI host bus 9