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If STDF (or ATDF) data appears "lost" due to an unexpected failure of the test system, there is a way to recover that data. For example, if lot testing is aborted, due to a software or hardware malfunction, such that the STDF Summary record is never created. An STDF Recovery agent can be used to assemble and recover the STDF log from the datalog objects stored in Guru. This note demonstrates the creation and usage of the STDF Recovery agent.



STDF data is generated when the operator presses "START" from a Test Exec. First, a "header" datalog object with LOT information is created, followed by part data "detail" datalog object stored in 100 DUTs or less and finally a "summary" datalog object with statistical data from the lot. The STDF copy agent assembles these pieces periodically by finding all unprocessed "summary" objects and concatenating the header, data, and summary to form the complete STDF file. Recovering "lost" STDF data looks for all unprocessed headers and generates STDF files with the unprocessed data objects. It is worth noting that the Summary statistical data is not calculated and not included in the recovered STDF files, the file ends with the last detail entry. Normal post-processing tools do not requires this summary data and so the recovered STDF files can be used just like a typical non-recovered STDF file. When a MatchOn property targets "header" instead of "summary", it will specifically avoid processing any datalog sequence that has a "summary" to prevent duplicate STDF data.
Example: Import these Guru STDF Copy Agent templates: "STDF Copy Agent" and "STDF Copy Recovery" agent.ExampleSTDFGuruAgents.gzpExampleSTDFGuruAgents.gzp





1. Run the "Guru Agent Editor" application by selecting it from Guru Apps button.



2. Open the "current" STDF Agent:

From the Editor, select "Guru | Open" from the pull-down menu.



Select the Agent that is currently used to automatically assemble and transfer STDF files, press "OK".



This will be used as a template in the creation of the manual STDF Recovery agent. (Selecting the same type of data, similar destination, etc)
ATTENTION! To prevent altering the "live" agent, DO NOT SAVE until all steps are complete, then use "Save-As" to save a new agent from this template.
3. Update MatchOn property:

Click the
MatchOn entry field (located at the upper left corner) to open the Match-On (Source Selection Criteria) dialog window.





Note the
Match On entry field near the bottom of the Dialog Window. The Match On entry field will have a line similar to this: "ri.sys.ObjClass=RiDataLog,ri.sys.Type=summary".

If both STDF and ATDF data is generated, the agent may use "ri.dlog.Format=STDF4" or "ri.dlog.Format=ATDF2" to distinguish between the two object types. The agent runs the same way (concatenates all lot data), but the file rename template would have to end with ".stdf" or ".atdf" for the file to be opened correctly.

Change the value of "ri.sys.Type=summary" to "ri.sys.Type=header".



The finished entry in this case is:
"ri.sys.ObjClass=RiDataLog,ri.sys.Type=header"


4. Convert to a manually run agent & change visibility:

Select
Execution from the Settings pull-down menu.



This is an important step, in order to prevent this agent from automatically running. If this recovery agent runs while testing, it will recover "files in progress". When that file is completed and marked as such, the normal STDF agent to perform its standard task, this time on the completed file. The result is the initial file entries will be copied to the destination folder twice, which may not be an issue with particular STDF processing tools.

Select option
"Inactive/Manual" from the "When to Run:" section.



Select "
Present a visible window when the agent runs."
De-select "
Automatically close the agent when its task is complete."

These changes cause the agent to open a window and display its actions when it runs. It allows the user to witness and evaluate the files recovered, the number of entries assembled, and see any information messages, warnings, and errors. The user can then close the Dialog box when the task is finished. Note that any warnings and errors displayed in the window are present in Guru as well if there is a need to review them after the Dialog is closed.

Press "OK" when done modifying the Execution settings.

5. (Optional) Save Recovered STDF to Different Destination?

Since this agent is based on the regular STDF copy agent, the destination fields are the same as for normal operations. If "recovered" files should go to a different destination or have a different name, then modify the Destination field as required
.

Change the fields:
Type of destination, Location, Rename Template, etc. as needed.

Example 1: Location changed from "T:\testdata\stdf" to "T:\testdata\stdf\
recovered\"
Example 2: Rename Template changed from "<ri.dlog.Device> <ri.dlog.Log>-<ri.dlog.Sublot> #Date1 <ri.dlog.StartTime>.stdf" to "
recovered <ri.dlog.Device> <ri.dlog.Log>-<ri.dlog.Sublot> #Date1 <ri.dlog.StartTime>.stdf"


6. Final Step (and most important): Do not forget to Guru | Save As instead of Save.

or

Save it to a new name such as
"Stdf Recovery". Note that a regular Save will overwrite the regular Stdf copy agent. (If this has happened, use Guru Browser to recover old version of the agent.)

Running the STDF Recovery Agent:

1. To recover partial STDF files, run the Guru Agent application by selecting it from Guru Apps bar.



2. From the list that appears, select the previously created Stdf Recovery Agent. (i.e. "Stdf Recovery")



3. If the recovery agent was configured to display a visible window, then agent activity will appear in a console window as any discovered STDF partial files are assembled and copied off. Otherwise the agent will perform its task silently.


4. Verify the files were located, assembled and copied to their destination by finding the files at the target location.



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