ABSTRACT
The I/O system is a critical bottleneck for many modern data-intensive applications. The demand for greater storage capacity and high-speed access to stored data is growing rapidly. Disks, the most common secondary-storage medium in use today» have shown remarkable improvements in capacity and performance over the past decade. Innovations in disk technology have resulted in higher recording densities, smaller form factors, increased spindle speeds, and the increased availability of multi-zoned disks with variable transfer rates. Nonetheless, the storage requirements of modern applications is growing at an even faster rate, exceeding the impressive capacity of modern disk drives, and necessitating the use of multiple storage devices. Simultaneously the I/O rates required by these applications has outstripped the data rates that can be provided by single disks, despite the very significant improvements that have been made.
