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What's Good About Allegro Database Locking? See for Yourself in 16.5!

Comments(2)Filed under: PCB design, SPB, Allegro PCB Editor, Allegro, PCB Editor, PCB, layout, design, SPB16.5, Allegro 16.5, database locking

Prior to the SPB16.5 release, multiple designers can edit and update the same Allegro PCB Designer design without conflict notification. To prevent this situation an advisory lock feature is now available in 16.5.

Read on for more details…

When opening a design for editing, Allegro PCB Designer will generate a lock file (<design>.lck). This lock file is maintained until Allegro PCB Designer exits, opens another design or writes a new design file. If a different program attempts to open this design, a warning message is presented which allows you to override or cancel your design open request:

A similar message is presented if you attempt to overwrite a locked design:


Typically as you edit a design, you may save the design to a new name. When this occurs the lock will be removed from the original design and created on the newly saved design.

For new designs (File> New), a lock file will not be created until the first time the database is written.

Advisory locking is NOT supported in the free viewers. Since the viewer plus program can write a database, it supports locking.


Netrev can be initiated by the Front-End tools to update a design. It supports locking for both the input and output designs. If either design is locked, netrev will fail with an error in netrev.lst.


Locking supports the variable allegro_nolocking. When this variable is set, programs will NOT create lock files, but will check for the presence of lock files before opening a design.

Per Project Journal File

Currently a program journal file (e.g. allegro.jrl) is opened in the starting directory of the program. This starting directory is typically the last directory from the last run of the program. On Windows, it is hard to track down the journal file location should the program fail.

The 16.5 release now creates a new journal file in the project directory of a design under edit. If you switch to a different design directory by opening a design in that directory, the current journal file will be closed and new journal initiated in the new project directory. The end result of this change is to associate the journal file with the project directory.

This new behavior is disabled under the following conditions:
•    You have specified a journal file when starting the program.
•    You have issued a journal command to start a new journal.

The sub-directory journal option (ADS_SDLOG) and the environment variables to modify the journal file naming are supported with the per project journal change.

As always, I look forward to your feedback on using this new 16.5 feature.

Jerry "GenPart" Grzenia


By Michelle on November 30, 2011
for 16.5, when auto backup is activated, will the auto lock also happen each time the file is saved?

By Jerry GenPart on December 1, 2011
Hi Michelle,
Well, regardless of auto backup enabled, since the PCB .brd file is open (being edited at the time), a lock file is in place.
Jerry G.

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