I studied it some back in college when I stumbled across the manual for it in our library.  But that's been quite some time.  So my memory is bound to be rusty at best.  However, I have recently gotten a reprint copy of the manual and would be happy to help out if you can't find anyone more suitable. BLS On Friday, October 9, 2020, 12:48:07 PM EDT, W. Bryan Caudle via vcf-midatlantic <vcf-midatlantic@lists.vcfed.org> wrote: Greetings!  I hope everyone here is doing well.  I was contacted recently by a gentleman from the University of Heidelberg who is doing research on the IBM ASCC, otherwise known as Harvard Mark I.  Specifically he is looking for understanding of its theory of operation and how the accumulators are used in calculations.  While I have some general knowledge and there are some resources online, he was hoping to connect with someone with more extensive knowledge of the machine.  If anyone here would be interested in talking with him, please let me know and I will introduce you, and feel free to share this with your network(s) if you feel you know someone who might be able to help. Thanks!