Also in the event that more than one Server is operated in single computer, failure in one subsystem should not delay processes in other subsystems and remaining part of Operator interface system should continue to work correctly while reset is made for faulty subsystem. 

Task at least which should be executed uninterruptedly are: 

 I/O device subsystems 

 Monitoring, reporting, distributing and acknowledging alarms 

 , Collecting, storing, distributing historical trends 

 Processing, storing and distributing reports 

 Storing and distributing configuration for remote client stations. 

 O, Network communication between operator interface stations. 

 Field device communication (in positions where field devices support). 

Software will be supplied as complete package. Additional software should not required for running or configuring all properties of system. 

Software should support workstation which can use upto 255 databases as single integrated system simultaneously. It should be able to expand system by adding hardware which is not special. 

It should be able to Operator Interface clients which belong to Operator Interface server to other server clusters by minimum engineering efforts. Operator interface clients should request and view live data, historical data and alarm data from Server in network without requiring restart or operator intervention. 

## 8.19.3 Operation Interface 

Software should use I/O server for reading and writing variables and tags in I/O(Input/output) subsystems. I/O servers should manage reading data from I/O device subsystems and writing to these systems and should provide these data for any client based upon request. 

I/O servers should read and write only request is received from client or server system within network for reducing network traffic and operational burden over field devices. 

I/O devices for proper protocols such as telemetri should have ability to collect time labeled data which comes from field equipments in addition to historical data in alarm and data log file. These information should be reproduced automatically in Operator interface historical records without requiring any user configuration or intervention. 

Software should be available for working as redundant by supplying second computer or license without requiring any user interface or creating program if necessary. 

All drivers which are present should be supplied together with software and included in price. Any additional license fee should not be necessary for use of one driver or all drivers. 

Instant process data which is present in system should be able to be transferred easily to any OPC client application over OPC DA 2.0 Server which is present in system, archive information for system will be transferred over OPC HDA 1.0 Server and alarms and events which may occur in system will be transferred over OPC AE Server. 

Software should have following connection options minimum for third party programs or databases without paying any fee.: 

