What Does ABEND 414-04 Mean?

Ran into this one recently and I thought I'd share. Essentially, a volume can be set to READ ONLY. This is something outside the scope of any security product that might be running on the system, meaning you may have RACF permissions to a data set, but if the volume on which that data set resides is READ ONLY, you'll get the 414 abend. The solution is to get your system programmer to un-read only the volume so you can write to it.