Notes about the ATL file extension:
Incorrect file associations could be the result of underlying issues within your PC system. As such it is highly recommended to scan your PC for invalid registry entries, unused processes and other unfavourable system settings to identify slowdown issues.
The ATL file type is primarily associated with 'ATP' by Brancepeth Computer Publications. The file is interpreted by the Assembler Training Program. The ATP is an integrated Editor Assembler Debugger. The ATP assembly language training program is widely used in UK and is freely available from the publisher's Web site.