I do hope no-one is taking this thread too seriously. The use of MVCIN to set a data area eyecatcher is incredibly inefficient.
If you really think that there it is important to ensure that data area eyecatchers aren't found in the code which creates them, you can copy the convention used internally by much of CICS, which is to move in a prefix character followed by the rest, so the prefix character is normally set with MVI and the rest with MVC. I've just compared a MVI, MVC sequence with a MVCIN instruction and it was more than 10 times faster on this machine. Jonathan Scott, HLASM IBM Hursley, UK
