CHAPTER 4 Command Reference
User’s Guide
49
Mutually exclusive sessions
A Historical Server connection can be involved with only one session at a
time. You can either be defining a recording session, or defining and
executing a playback session, but you cannot mix together commands for
multiple sessions. That is, if you start a recording session definition with
the
hs_create_recording_session
command, you must finish the sequence
of commands to define that session (or cancel the session) before you can
start to define a playback session or a new recording session.
Defining a recording session is not the same thing as a recording session
in progress. The user who defines a recording session is connected to and
actively communicating with Historical Server during definition of a
recording session. The user does not actively communicate with Historical
Server during the actual recording. Any user connections are irrelevant
during recording. For example, a user might connect to Historical Server
at 3 p.m., define a recording session that starts at 10 p.m., and then
disconnect from Historical Server. At 10 p.m., it is irrelevant whether the
user is connected to Historical Server; the recording session takes place if
Historical Server is running.
A playback session, however, requires the user connection during both
playback definition and playback execution. To cancel playback execution
and allow the user connection to perform some other communication, the
user must issue the
hs_terminate_playback
command.
Starting and ending a recording session definition
The
hs_create_recording_session
command starts a recording session
definition. After issuing this command, you further define the recording
session by issuing other commands to create views, filters, and alarms for
the recording session.
To end the recording session definition, use either:
•
hs_initiate_recording
– signals that the definition is complete and
enables the recording session to start at the session’s specified start
time.
•
hs_terminate_recording
– cancels a recording session definition that is
in progress.
Summary of Contents for 12.5.1
Page 1: ...User s Guide Historical Server 12 5 1...
Page 14: ...xiv Historical Server...
Page 46: ...Configuring multiple instances of Historical Server 32 Historical Server...
Page 56: ...Starting and stopping Historical Server on Windows NT 42 Historical Server...
Page 102: ...hs_terminate_recording 88 Historical Server...
