====I/O Servers====

An I/O Server is a computer system (often a virtual machine) that gathers information for ARDI.

Your ARDI server itself is normally your main I/O server, but administrators may choose to move some of the data-gathering to different systems.

This may be for one of several reasons....

   * To reduce load on the server by offloading data aquisition to a different system.
   * To take advantage of drivers that are only compatible with different operating systems.
   * To work around security issues

As an example, there is an HMI package named Citect that ARDI supports. However, the driver is only suitable for Windows-based machines.

A Linux-based ARDI server can still access Citect information if you set up a Windows system on the network as an **IO Server** - that way, the Windows machine gathers data and transmits it to the Linux system.