PD KSH source?

[Chin Fang]

I heard about this PD KSH for quite a while but still have not found
out where to get it.  Would someone knowledgeable post some info
regarding

(1) where it is available (ftp sites would be most welcome)
(2) problems with it so far
(3) difference between the pd version and the AT&T version
(4) if possible, difference between it and the Born Again Shell from 
    FSF?  (I could not get the ksh, so I was considering building the
    later)
(5) unix used (Interactive, ESIX, UHC, Microport ...)

Thanks to anyone who will post

Chin Fang
Mechanical Engineering Department
Stanford University
fangchin at portia.stanford.edu
fang at rocket.cadcam.rok.com