[StrawberryFrog]

I'd guess WordStar. Or failing that, WordPerfect.

WordPerfect was more commonly seen, but WordStar fits the description of "Runs on CP/M and is not supported" better.

Edit: See here: http://en.wikipedia.org/wiki/WordStar#Abandonment

[cstross]

Nope: Protext.

http://www.tigerteam.co.uk/protext/

[keithpeter]

NC100 - got it

[2mur]

George R.R. Martin writes on WordStar.

http://www.goodreads.com/author_blog_posts/1220865-talking-a...