This is a text editor that a solid part of the IbmEditorFamily. It looks a lot like cse or SlickEdit.
No longer available but this is such a popular member of the IbmEditorFamily that clones exist. For example, PE32
There is an excellent paper on "Reading and Writing with Computers" that mentions PE:
http://www-2.cs.cmu.edu/~wjh/papers/framework.html