/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.

---

/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).

---

/Experiment/Buffer Sizes/SYSMSG

• Type: DWORD
• Default: 100000 Bytes

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

---

/Experiment/Buffer Sizes/SYSTEM

• Type: DWORD
• Default: 8MBytes

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

---

/Experiment/MAX_EVENT_SIZE

• Type: DWORD
• Default: 4MBytes

The key specifies the maximum event size that can be acquired. The default value is half the size of the SYSTEM buffer. It can be increased if required (see Event Buffer).

---

/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. Without the "Pause" being present in the list of menu buttons, the run cannot be paused/resumed, but only started/stopped. This is required by some experiments.

If MSCB support is built into MIDAS, the MSCB Menu button will also be shown.

---

/Experiment/Transition debug flag

• Type: INT
• Default: 0

If flag is set to 1, messages reporting transition progress will be output.

---

/Experiment/Transition connect timeout

• Type: INT
• Default: 10000

Value of timeout for remote rpc connect

---

/Experiment/Transition timeout

• Type: INT
• Default: 120000

Value of timeout for transition

---

/Experiment/Prevent start on alarms

• Type: BOOL
• Default: "n"

Setting this key true will prevent the run from starting if an alarm is true.

---

/Experiment/Prevent start on required program

• Type: BOOL
• Default: "n"

Setting this key true will prevent the run from starting if one of the required clients is not running.

---

---

/Experiment/Start-Stop Buttons

• Type: BOOL
• Default: "y"

---

/Experiment/Pause-Resume Buttons

• Type: BOOL
• Default: "n"

---

/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.

---

/Experiment/Parameter Comments subtree

This optional subdirectory may contain user-defined parameter comments that give more information about the Edit-on-start Parameters. See creating parameter comments.

---

/Experiment/Lock when running subtree

This optional subdirectory contains user-defined links to ODB parameters to prevent them being changed when the run is in progress. See Lock when running for details.

---

/Experiment/Security subtree

This optional subtree is created when the odbedit commands passwd or webpasswd are issued. It enables a user to set up security features. See Security

---

/Experiment/Security/Password

• Type: STRING
• Default:

Contains the encrypted password. Key is created when odbedit command passwd is issued. See security for details.

---

/Experiment/Security/Allowed hosts subtree

This subtree is created when odbedit command passwd is issued. When created, this subtree is empty. It may contain names of remote hosts allowed to have free access (i.e. without password) to the current experiment. See allowed hosts.

---

/Experiment/Security/Allowed programs subtree

This subtree is created when odbedit command passwd is issued. When created, this subtree is empty. It may contain names of clients allowed to have free access (i.e. without password) to the current experiment. See allowed clients.

---

/Experiment/Security/Web Password

• Type: STRING
• Default:

If web access restriction has been set up, this key will contain an encrypted password for Web server access. Key is created when odbedit command webpasswd is issued.

If this key is present, the user will be requested to provide the "Web Password" when accessing the requested experiment in "Write Access" mode. The "Read Only Access" mode is still available to all users.