The Free On-line Dictionary of Computing (30 December 2018):

pdksh

   Version 4.9

   interpreter

   Simon J. Gerraty 

   comp.sources.misc volume 4

   It is not intended to be the ultimate shell but rather a
   usable ksh work alike.

   conformance:	Almost identical to ksh88, but missing arrays

   E-mail: Simon J Gerraty  (zen.void.oz.au
   is down)

   ports:		Sun, 386bsd, ?

   1993-10-11