2 – I/O

Publisher Summary Data is a vital and central element of business information technology, and the characteristics of storage systems are important factors in the choice of a server that makes the choice of storage and communication technologies extremely crucial. I/O is a key part of a system, which drives the system's performance and provides an opportunity to add a value to the system. Communications support for both local and wide area is also vital and thus specialized subsystems connected to servers have also developed. The ideal requirements in storage subsystems include: increasing capacity, performance, and availability coupled with steadily reducing cost per gigabyte. An I/O storage system comprises of number of elements each having a vital function of its own. It includes a system controller, I/O buses, directly attached magnetic peripherals, and specialized networks. This chapter reviews buses used for I/O in particular PCI and its extensions, connections between controllers and magnetic peripherals with emphasis on SCSI and fibre channel, bitrated loop, and connections to connect to peripheral subsystems. The chapter also discusses the future prospects of the InfiniBand I/0 proposal, which might be successful in the coming years.