Interesting part

One of the early proof-of-concept designs for the Friden 130 (http://oldcalculatormuseum.com/friden130.html) used a magnetic drum, but in final production, the machine used a magnetostrictive delay line. The Canon 167 (http://www.oldcalculatormuseum.com/w-can167.html) used a small magnetic drum for register storage. Also, the Wyle Laboratories WS-01 (precursor to the WS-02, seen at http://www.oldcalculatormuseum.com/w-wyle.html), an interesting and very early programmable calculator used a small magnetic disc memory. More information at http://oldcalculatormuseum.com/d-compucorp.html. Not many Wyle Labs WS-01's were sold. They had a lot of troubles with the small disc memory, which prompted the retooling to use a magnetostrictive delay line as the WS-02. So far as I know now, the only machine that used a mag disc/drum that was sold in production quantities was the Canon 167. Earlier 'desk-sized' (not desktop) calculators, such as the Monroe Monrobot I and II, the Clary DE-60, SCM 7816, and others, used magnetic drum memory almost exclusively. Rick Bensene The Old Calculator Web Museum --- I wrote, and Sellam replied: