/Experiment ODB tree

Creating the /Experiment tree

The /Experiment ODB tree is created automatically when the ODB is first created.

Purpose

The /Experiment ODB tree contains information relevent to the experiment. Other optional keys are added by mhttpd or by the user to customize their experiment.

Examples

When initially created, the /Experiment tree contains the following keys:

[local:midas:S]/>ls -lrt /experiment
Key name                        Type    #Val  Size  Last Opn Mode Value
---------------------------------------------------------------------------
Experiment                      DIR
   Name                        STRING  1     32    14s  0   RWD  midas
   Buffer sizes                DIR
       SYSMSG                  DWORD   1     4     11h  0   RWD  100000

The following example shows the /Experiment tree for the DEAP experiment :

[local:deap:R]/>ls -lrt /experiment
Key name                        Type    #Val  Size  Last Opn Mode Value
---------------------------------------------------------------------------
Experiment                      DIR
   Name                        STRING  1     32    7s   0   RWD  deap
   Buffer sizes                DIR
       SYSMSG                  DWORD   1     4     23h  0   RWD  100000
       SYSTEM                  DWORD   1     4     23h  0   RWD  640000000
       BUF0                    DWORD   1     4     23h  0   RWD  80000000
       BUF1                    DWORD   1     4     23h  0   RWD  80000000
       .......    other user-defined buffers not shown  
   MAX_EVENT_SIZE              DWORD   1     4     23h  0   RWD  4194304
   Menu Buttons                STRING  1     256   5h   0   RWD  Status, ODB, Messages, Elog, Alarms, Programs, History, MSCB, Sequencer, Config, Help
   Transition debug flag       INT     1     4     23h  0   RWD  0
   Transition connect timeout  INT     1     4     23h  0   RWD  10000
   Transition timeout          INT     1     4     23h  0   RWD  120000
   edit on start               DIR
       Pedestals run           BOOL    1     4     2h   0   RWD  n
       Write Data -> /Logger/Write data
                               BOOL    1     4     2h   0   RWD  n
       Comment -> /Experiment/Run Parameters/Comment
                               STRING  1     80    2h   0   RWD  Sequenced Tests
   Run Parameters              DIR
       Comment                 STRING  1     80    2h   0   RWD  Sequenced Tests
       Run Description         STRING  1     256   7h   0   RWD  Sequenced Tests
   Prevent start on alarms     BOOL    1     4     22h  0   RWD  n
   Prevent start on required prBOOL    1     4     22h  0   RWD  n
   Status items                DIR
       Experiment Name -> /Experiment/Name
                               STRING  1     32    7s   0   RWD  deap
   Start-Stop Buttons          BOOL    1     4     5h   0   RWD  y
   Pause-Resume Buttons        BOOL    1     4     5h   0   RWD  n

Keys in /Experiment tree

The keys in the ODB /Experiment tree are described in the following sections.

/Experiment/Name

• Type: STRING
• Default:

Contains the name of the experiment. Filled automatically when the ODB is created with

---

/Experiment/Buffer Sizes subtree

Contains the sizes of the Midas Buffers for the experiment. Created with default values. The sizes can be changed to optimize the memory usage. See Event Buffer Size(s) for details. Other user-defined buffers may be present (e.g. for event filtering).

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/Experiment/Buffer Sizes/SYSMSG

• Type: DWORD
• Default: 100000 Bytes

Contains the size of SYSMSG buffer. This buffer is used for MIDAS messages.

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/Experiment/Buffer Sizes/SYSTEM

• Type: DWORD
• Default: 8MBytes

Contains the size of SYSTEM buffer. See Event Buffer for details.

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/Experiment/Menu Buttons

• Type: STRING
• Default: "Start, Pause, ODB, Messages, ELog, Alarms, Programs, History, Sequencer, Config, Help"

This key is added automatically by mhttpd to allow the Menu buttons that appear on the mhttpd Main Status Page to be customized by removing unnecessary buttons or by changing their order. If MSCB support is built into MIDAS, the MSCB Menu button will also be shown.

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/Experiment/Edit on Start subtree

This optional subdirectory contains user-defined parameters which will be displayed for editing at the beginning of each run. See Edit-on-start Parameters for details.

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/Experiment/Lock when running subtree

This optional subdirectory contains user-defined parameters which cannot be changed when the run is in progress. See Lock when running for details.

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/Experiment/Security subtree

This optional subtree enables a user to set up security features. See Security

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