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

Mark I

    (Or "Automatic Sequence Controlled Calculator",
   "ASCC") A first generation computer that was designed by
   Howard Aiken of Harvard University, taking inspiration
   from Charles Babbage's Analytical Engine.  The Mark I, as
   the Harvard University staff called it, was built by IBM
   between 1939 to 1944.  It was delivered to Harvard University
   and became operational in March 1944.

   The Mark I is considered to be the first full-sized digital
   computer.  It was built from clutches, relays, rotating
   shafts and switches.  It read its instructions from one paper
   tape and data from another.  It could store 72 numbers, each
   of 23 decimal digits.  It weighed about 4500 Kg, had 800 Km of
   wiring, was used only for numeric calculations, and took three
   seconds to carry out one multiplication.  The IBM archives
   call it the, "...industry's largest electromechanical
   calculator."

   One of the Mark I's first programers was John von Neumann.
   The Mark I was retired in 1959, and disassembled.  Parts are
   archived at Harvard in the Science Center.

   It was followed by the Mark II.

   (1996-11-24)