The 1401 was designed as a stored-program alternative to IBM's never-shipped WWAM World Wide Accounting Machine. WWAM was designed in IBM Europe in 1955. WWAM was to be a low-cost plugboard-programmed transistor computer to handle the same card tasks as IBM's existing and popular relay-based punch-card accounting equipment. WWAM was IBM's reaction to the threat of losing its many punch-card customers to a low-cost computer Gamma 3 made by French company Bull. 1401 uses the same ALU etc as WWAM, but with newer standard circuit modules. Both use arbitrary-length decimal fields, just like the punch card machines before them.Several incompatible IBM machines in the 7000 series also used arbitrary length decimal numbers, not binary words.
At Burroughs, the "Medium Systems" B2500-B4800 series were similarly decimal only with arbitrary length numbers. They got extended with fixed-length decimal accumulator and index registers, and competed with IBM's mid range 360 and 4331 systems. Building a decimal-addressed memory using binary-addressed chips got increasingly kludgy.
https://ibm-1401.info/1401Origins.html#Motivations-1
masswerk|2 years ago
On the Bull Gamma 3: http://www.feb-patrimoine.com/english/gamma_3.htm
The Register had once a nice article on the occasion of the 1401's 50th anniversary: https://www.theregister.com/2009/11/17/ibm_1401_fiftieth_ann...