Understand Data Archive subsystems and dependencies
- Last UpdatedFeb 20, 2025
- 2 minute read
Some Data Archive subsystems depend on other subsystems for proper behavior. All subsystems wait at startup for any dependent subsystems. The executable for each subsystem is installed in the PI\bin directory. Data Archive subsystems run as Windows services. You can check the status of these services in the Windows Services tool or in System Management Tools (Operation > PI Services).
Data Archive core subsystems
Data Archive requires the following core subsystems.
|
Subsystem |
Executable |
Purpose |
Dependencies |
|---|---|---|---|
|
AF Link |
piaflink.exe |
Synchronizes PI MDB and PI AF. |
Network Manager |
|
Archive |
piarchss.exe |
Stores and serves the data after it comes out of the snapshot subsystem. Data consists of multiple time-stamped measurements for each data point. |
Snapshot Update Manager License Manager |
|
Base |
pibasess.exe |
Maintains the Point Database, Digital State Table, and configuration databases for authentication; hosts the PI Module Database; validates user logins. |
Update Manager License Manager |
|
License Manager |
pilicmgr.exe |
Maintains license information for Data Archive and all connected applications. |
|
|
Message |
pimsgss.exe |
Records status and error messages for Data Archive in a log file. |
If this subsystem is not available, messages are routed to the Windows event log. |
|
Network Manager |
pinetmgr.exe |
Manages communication between Data Archive subsystems, interfaces, and client applications. Also validates clients at connection time. Clients are standard products such as PI Vision and PI DataLink. |
|
|
Snapshot |
pisnapss.exe |
Stores the most recent event for each point, applies compression, sends data to the event queue, serves snapshot events, and sends updates for client applications to PI Update Manager. |
Update Manager License Manager |
|
Update Manager |
piupdmgr.exe |
Queues notifications of changes in data values, point attributes, modules, and so on to any interface or client application that is signed up for notification. |
Essential for proper operation of Data Archive; most subsystems and client applications require it. |
Data Archive non-core subsystems
Non-core subsystems are not essential to run Data Archive. .
|
Subsystem |
Executable |
Description |
|---|---|---|
|
Alarm |
pialarm.exe |
Provides alarm capabilities for PI points. |
|
Backup |
pibackup.exe |
Manages Data Archive backups. |
|
Batch |
pibatch.exe |
Detects and records batch activity. This subsystem is licensed separately and might not be installed on your Data Archive server. |
|
Performance Equations |
pipeschd.exe |
Performs Performance Equation (PE) calculations for PE points. |
|
Recalculator |
pirecalc.exe |
Recalculates values of PE points after historical changes. |
|
Shutdown |
pishutev.exe |
Determines when Data Archive was stopped and writes shutdown events to points configured to receive these events. It runs only at startup and then stops. |
|
SQL |
pisqlss.exe |
Prepares and executes SQL statements directed at Data Archive. The primary users of this subsystem are the PI ODBC Driver and the PI SDK. |
|
Totalizer |
pitotal.exe |
Performs post-processing calculations on a point in the snapshot and stores the results in a PI Totalizer point. |