The HOMEPAGE and MASTER_SITES of pstree seem dead:
http://www.thp.uni-duisburg.de/pstree/
ftp://ftp.thp.uni-duisburg.de/pub/source/Apparently, the Uni's site is www.uni-due.de now and Fred Hucht is still at https://www.uni-due.de/thp/ but the http/ftp structure is not preserved. Is it worth having pstree now that we have ps -f? Jan
