Fault Resilient Computer

A fault-resilient computer is the computer in computer telephony. Both fault-resilient and fault-tolerant computer systems have high availability - they are more reliable than conventional PCs, allowing them to be used in mission critical systems (characterized by such things as high port count, multiple applications, use by service providers and Central Offices) or applications where revenue is generated on a minute-by-minute basis, such as prepaid calling card systems and enhanced services systems.

Using a conventional off-the-shelf PC for computer telephony applications can be an enormous mistake, since ordinary PCs are not designed for mission critical applications such as telephony. Standard PCs work most of the time, but most of the time is not good enough for mission critical applications.

When a single PC or LAN fails in a non-telecom environment, it may create some inconvenience to a single user or even perhaps a few departments. The failure of a mission critical CT application, however, results in a catastrophic minute-by-minute loss of revenues, or, in the case of Enhanced 911 systems, puts the public in danger. The best strategy for averting such a situation is to ensure that your platform is designed specifically for CT applications.

A fault-resilient system, for example, will remain up about 99.99% of the time, or will suffer downtime for only about 52 minutes a year. A fault-tolerant system will be up five nines or 99.999% of the time, which amounts to about five minutes per year of downtime. Some of the latest systems...