Since the integrated file system (IFS) was introduced for OS/400, the predecessor of IBM i, directory and file names were internally stored in Unicode with a CCSID 13488 (UCS-2). However, the SAP kernel only supported the 7-bit ASCII character set for file and directory names, mainly the letters a to z, A to Z, the digits 0 to 9 and some special characters. Using other characters in a name could result in incorrect output when the directories were viewed through a different interface.
With the Unicode version of stack kernel 7.53, patch level 600, directory and filenames can now use the full Unicode character set. In the following ABAP statement, MyFile can be any valid Unicode character string:
OPEN DATASET MyFile (…) encoding utf-8.
Be aware that the kernel enhancement only guarantees that the file or directory name is stored and handled properly through SAP interfaces. If you access the directory through another interface that is not Unicode capable and cannot represent one or more characters in the name, you may still see incorrect output through that interface. For example, if you use the Greek letter ‘alpha’ in your filename, you only will see the correct character through WRKLNK in your 5250 emulation, when your terminal session is running with the Greek EBCDIC CCSID 875.