Date   : Sat, 23 Jun 1984 18:20:00-EDT
From   : Stephen C. Hill <STEVEH@Mit-Mc.ARPA>
Subject: zcpr et al

Basically each of the ZCPRs are independent, upgraded versions of the earlier
numbered ZCPRs.  These are effectively replacements of the part of the CP/M
operating system that processes terminal input to the OS.  Rich Conn has then
written many utility programs, that have been long needed.

I would recommend that you don't waste your time on the ZCPR(1) files, perhaps
pull down the documentation files from ZCPR2, just for background, and go
directly to ZCPR3.