Control systems on low cost computers

Computing infrastructures for accelerator control systems can now be built using low cost, commodity-type computers. The commonly used EPICS control system toolkit has been adapted to facilitate its deployment on Pentium-based PCs running the Linux operating system, as well as on other inexpensive platforms. Low-cost, reliable enterprise-class computers can be obtained from many commercial vendors for such control system network-based services as Domain Name Service (DNS), Network Information Services (NIS), and Dynamic Host Configuration Protocol (DHCP). Control system file servers can also be configured using inexpensive rack-mounted PCs and multiple monitor operator consoles can be built with Linux-based PCs or standard X-windows software with high performance video graphic adapters. At the front end of the control system, input-output controllers can be configured also as PCs running embedded Windows. Several accelerator laboratories, including the Spallation Neutron Source (SNS) at the Oak Ridge National Laboratory are taking advantage of these possibilities. This paper will review the use of inexpensive computers in the accelerator community, with particular emphasis on the issues and applications at SNS.