Hi, This is a belated response to a post you made here: http://www.classiccmp.org/pipermail/cctech/2003-February/010641.html I happened upon it while doing a 'for fun' search on the net for anything doing with good ol' Century Data, my employer when I was young. Couldn't resist responding to the post, even if it was half a year late! The exerciser that you have is/was for the Trident series of hard disk drives (predecessor to the Marksman). I was the main (in fact, pretty much the ONLY) technician at Century Data/Calcomp, for these exercisers back from the late 1970's to the mid 1980's, when they were phased out. I retired in 1985. Have fun! (BTW, where'd you find one of these dinosaurs??) Take care, Nasim