About Layers and Difference between Layers

Layer: a layer system is used to manage elements.
The USR layer is the top layer and the SYS layer is the bottom layer, and each layer has a corresponding patch layer above it.

USR: The user layer is for user modifications, such as reports.
CUS:The customer layer is for modifications that are specific to a company.
VAR:Value Added Resellers (VAR) 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.
ISV:When an Independent Software Vendor (ISV) creates their own solution, their modifications are saved in the ISV layer.
SLN:The solution layer is used by distributors to implement vertical partner solutions.
FPK:The FPK layer is an application object patch layer reserved by Microsoft for future patching or other updates.
GLS:When the application is modified to match country or region specific legal demands, these modifications are saved in the GLS layer.
SYS:The standard application is implemented at the lowest level, the SYS layer. The application objects in the standard application can never be deleted.

Patch Layers:Each layer in Microsoft Dynamics AX has a corresponding patch layer that can be used to incorporate updates to your application or to store conflicts when you import models into a layer.

Microsoft only:

• SYS/SYP: System Layer
• GLS/GLP: Globalization Layer
• FPK/FPP: Future Pack Layer

Partners and ISV:

• SLN/SLP: Solution Layer
• ISV/ISP: Independent Software vendor Layer
• VAR/VAP: Value Added reseller

Partners and customers:

• CUS/CUP: Customer Layer
• USR/USP: User Layer 

Differences between Layers in Axapta 4.0, 5.0 and 6.0 :

 

 

 

 

 

Error and Warning Messages

List of Errors and Warning Messages in Axapta Ax 4.0, 2009 & 2012

http://msdn.microsoft.com/en-us/library/bb530207(v=ax.10).aspx in Ax-4.0

http://msdn.microsoft.com/en-us/library/bb530207(v=ax.50).aspx  in Ax-2009

http://msdn.microsoft.com/en-us/library/bb530207.aspx  in Ax-2012