▁the ▁two ▁machines ▁be ▁compared ▁for ▁the ▁purpose ▁of ▁using ▁them ▁for ▁a ▁J oint ▁N umer ical ▁We ather ▁Pred iction ▁project . ▁Based ▁on ▁the ▁tri als , ▁the ▁two ▁machines ▁had ▁compar able ▁computational ▁speed , ▁with ▁a ▁slight ▁advantage ▁for ▁IBM ' s ▁machine , ▁but ▁the ▁latter ▁was ▁fav ored ▁un anim ously ▁for ▁its ▁significantly ▁faster ▁input - output ▁equipment . ▁ ▁The ▁successor ▁machine ▁was ▁the ▁UN IV AC ▁ 1 1 0 3 A ▁or ▁Un iv ac ▁Scient ific , ▁which ▁improved ▁upon ▁the ▁design ▁by ▁replacing ▁the ▁un re li able ▁Williams ▁t ube ▁memory ▁with ▁magnetic - core ▁memory , ▁adding ▁hardware ▁floating - point ▁instructions , ▁and ▁perhaps ▁the ▁earliest ▁occurrence ▁of ▁a ▁hardware ▁interrupt ▁feature . ▁ ▁Techn ical ▁details ▁The ▁system ▁used ▁electro static ▁storage , ▁consisting ▁of ▁ 3 6 ▁Williams ▁tub es ▁with ▁a ▁capacity ▁of ▁ 1 0 2 4 ▁bits ▁each , ▁giving ▁a ▁total ▁random ▁access ▁memory ▁of ▁ 1 0 2 4 ▁words ▁of ▁ 3 6 ▁bits ▁each . ▁Each ▁of ▁the ▁ 3 6 ▁Williams ▁tub es ▁was ▁five ▁inches ▁in ▁diameter . ▁A ▁magnetic ▁drum ▁memory ▁provided ▁ 1 6 , 3 8 4 ▁words . ▁Both ▁the ▁electro static ▁and ▁drum ▁mem ories ▁were ▁directly ▁address able : ▁addresses ▁ 0 ▁through ▁ 0 1 7 7 7 ▁( Oct al ) ▁were ▁in ▁electro static ▁memory ▁and ▁ 0 4 0 0 0 0 ▁through ▁ 0 7