In November 1967, the journal Electronics reported[1]:

The price is right

-- even with cores

Japanese firm produces $900 desk calculator with new techniques

In the U.S., it's considered uneconomic to use magnetic core memory registers in electronic desk calculators. Acoustic delay lines are employed instead. cores are rarely designed into data processing systems which store less than about 10,000 bits.

Not so in Japan. Casio Computer Co. of Tokyo adds to the growing list of electronic calculators with an entry which will sell for $900 in Japan. Like the Hayakawa Electric Co. [Sharp] unit its internal registers are made of magnetic cores.

Masakatsu Ara, Casio's submanager for new product development, says the low price is possible partly because of the magnetic core registers.

The limiting factor in core memories lies in the electronic circuitry which decodes addresses, drives current through the wires in the memory, and senses the output signals. Casio has used several techniques to help keep these costs down and make the use of cores economically feasible.

Noise dies. For one thing, the memory is designed to operate at very low speeds; at these speeds the pulse signals have relatively slow rise and fall times, and therefore generate little noise. In fact, capacitively-coupled crosstalk is virtually nonexistent. There is also plenty of time for the noise that is generated to die away; the sensing circuits need not have a high noise-rejection capability. Thus the circuits themselves can be simpler and can be built with wide-tolerance components.

Another important design feature is the serial loading and unloading of registers, one digit, or four bits, at a time. The memory has only four sense amplifiers and four write drivers, compared to the dozen or two of each found even in small computer memories.