Diff between logical and physical file path

Question

Hi ,
Could you please explain difference between logical and physical file path's and their importance in ABAP.
Thanks and regards,
shyla

Answer 1

Hi
The function module FILE_GET_NAME convert a logical path into its corresponding physical path.
The advantage of using logical pathes within your applications is obivous:
If you need to change the physical path you just adjust it within transaction FILE yet no changes are required to your application.
http://help.sap.com/saphelp_erp2005vp/helpdata/en/25/ab3a57df3b11d189fc0000e829fbbd/frameset.htm
The file names that you use in ABAP statements for processing files are physical names. This means that they must be syntactically correct filenames for the operating system under which your R/3 System is running. Once you have created a file from an ABAP program with a particular name and path, you can find the same file using the same name and path at operating system level.
Since the naming conventions for files and paths differ from operating system to operating system, ABAP programs are only portable from one operating system to another if you use the tools described below.
To make programs portable, the R/3 System has a concept of logical filenames and paths. These are linked to physical files and paths. The links are created in special tables, which you can maintain according to your own requirements. In an ABAP program, you can then use the function module FILE_GET_NAME to generate a physical filename from a logical one.
Maintaining platform-independent filenames is part of Customizing. For a full description, choose Tools ® Business Engineer ® Customizing, followed by
Implement. projects ® SAP Reference IMG. On the next screen, choose Basis Components System Administration ® Platform-independent File Names.
For a more detailed description of the function module FILE_GET_NAME, enter its name on the initial screen of the Function Builder and choose Goto Documentation. On the next screen, choose Function module doc.
Another way of maintaining platform-independent filenames is to use the Transaction FILE. The following sections provide an overview of the transaction.
To create a logical filename, choose Logical filename definition, client-independent from the Navigation group box in Transaction FILE, then choose New entries. You define logical filenames
You can either define a logical filename and link it to a logical path (as displayed here), or you can enter the full physical filename in the Physical file field. In the latter case, the logical filename is only valid for one operating system. The rules for entering the complete physical filename are the same as for the definition of the physical path for the logical file. To display further information and a list of reserved words, choose Help.
If you link a logical path to a logical file, the logical file is valid for all syntax groups that have been maintained for that logical path. The filename specified under Physical file replaces the reserved word  in the physical paths that are assigned to the logical path. To make the name independent of the operating system, use names that begin with a letter, contain up to 8 letters, and do not contain special characters.
Save your changes.