The styling, attributed to Marco Zanuso but in reality by Mario Bellini, was ergonomical and innovative for the time.

Some of the design was based on a 1961 Olivetti computer co-developed by Federico Faggin that served as a model for the programmable calculator.

[8] The computational hardware consisted of standard (for its time) discrete devices (transistors, diodes, resistors and capacitors mounted on phenolic resin circuit card assemblies).

A total of 240 bytes of information were electrically stored in magnetostrictive delay-line memory, which had a cycle time of 2.2 milliseconds.

The Programma 101 can calculate the four basic arithmetic functions (addition, subtraction, multiplication, and division), plus square root, absolute value, and fractional part.

It is equipped with memory registers with features such as clear, transfer, and exchange, plus printing and halt for input.

Each full register holds a 22-digit number with sign and decimal point or 24 instructions each consisting of a letter and a symbol.

That was a common feature in the 1960s desktop computer/programmable calculator and only HP provided a true Von Neumann architecture which allowed for self-modifying code,[12] similarly to the contemporary general-purpose mainframes and minicomputers.

[...] We would have to run four separate programs on this Programma 101 [...]The P101 is mentioned as part of the system used by the US Air Force to compute coordinates for ground-directed bombing of B-52 Stratofortress targets during the Vietnam War.