Sharing the knowledge : Layers + AX 2012

Application Object Layers

Application object layers hold everything in the Application Object Tree (AOT).

The layers are a hierarchy of levels in the application source code to ensure that you can make modifications and additions without interfering with the application objects on the level below your own. When you make an object modification on one level, the modification overshadows the object on a lower level. You could for example choose to add e-mail information to a standard form. The addition would be saved on your level only; the revised form would replace the standard form, but you would always be able to go back to the original one on the level below your own simply by removing the new form.
Three customer groups have an interest in adding and modifying application objects:

Application developers who create the standard application

Business partners

End users of Microsoft Dynamics AX

Each of these three groups has two layers in which they can add and modify.

SYS	The standard application is implemented at the lowest level, the SYS layer. The application objects in the standard application can never be deleted.
GLS	When the application is modified to match country/region specific legal demands, these modifications are saved in a separate layer, the GLS layer. If an application object, for example a form, is modified in the GLS layer the modifications are saved in the GLS layer only and Microsoft Dynamics AX ensures that the modified version of the forms is used.
DIS	When the application is modified to match country/region specific legal demands, these modifications are saved in a separate layer, the DIS layer (for DIStributor). If an application object, for example a form, is modified in the DIS layer the modifications are saved in the DIS layer only and Microsoft Dynamics AX ensures that the modified version of the forms is used.
LOS	A layer where the distributor can implement local partner solutions. LOS is short for LOcal Solution.
BUS	When a business partner creates their own generic solution, their modifications are saved in the BUS layer and Microsoft Dynamics AX ensures that the top level application objects are used.
VAR	Value Added Resellers can make modifications or new developments to the VAR layer as specified by the customers or as a strategy of creating an industry specific solution. Such modifications are saved in the VAR layer.
CUS	The supervisor or administrator of an end-user installation might want to make modifications that are generic to the company. Such modifications are saved in the CUS (CUStomer) layer.
USR	End users might want to make their own modifications, for example their own reports. Their modifications are saved in the USR layer.

Each layer is saved in a separate file called Ax<layer>.aod, for example Axsys.aod for the SYS layer, Axdis.aod for the DIS layer and so on. The .aod extension is an acronym for Application Object Data file.

Layers in AXAPTA

Application Object Patch Layers

In addition to the eight layers in Microsoft Dynamics AX, each layer has a patch layer. The patch layers are called SYP, GLP, DIP, LOP, BUP, VAP, CUP, and USP.
The patch layers are designed to make it easy to incorporate updates in your current application. The basic idea is that when a minor update or correction is made, it is distributed in a patch file, for example Axsyp.aod. When a patch file is present, the modified objects in the patch file take precedence over the regular objects and are automatically used.

The patch files use the same number series as the regular files use.
The major benefit of the patch layer concept is that you can easily create and distribute an update. for example by using the Internet, without interfering with the existing application. When you subsequently incorporate the update in the regular layer file, you can delete the patch file (Ax??p.aod ) and the index file (Axapd.aoi).

Benefits of Layers

The fact that each layer is saved in a dedicated file means that it is easy to locate the file to backup. It also means that you can easily remove undesired modifications by deleting the layer file.


If you delete the layer file, you should also delete the index file to make the system regenerate it.

Any users of the Microsoft Dynamics AX application, whether a distributor, a business partner or an end user, can customize the Microsoft Dynamics AX application to suit their needs.

The standard application is never overwritten.

When you delete an object, you delete it in the current layer only.

If u want to change layers path is :

Open the Configuration Utility (Start > Control Panel > Administrative Tools > Microsoft Dynamics AX Configuration Utility).