David Hess (davidwhess.delete@this.gmail.com) on August 2, 2022 10:24 pm wrote:
>
> Core memory was contemporaneous with SRAM, DRAM, ROM, PROM, UVEPROM, and floppy disk storage.


Only the latest versions of core memory have overlapped in time the earliest versions of those kinds of memory, during the seventies.

Some forms of DRAM and of ROM are older than the core memories, so during the fifties the early core memories were simultaneous with them, but those early DRAM and ROM were very different from their later semiconductor counterparts, i.e. they were implemented with cathode-ray tubes and with discrete diode arrays, respectively.


When the core memories have been introduced, around 1953 to 1954, there were many competing memory technologies. Most of those have disappeared very quickly, so for about a decade and a half the core memories had no alternative for the central memory, until the semiconductor memories became competitive in integrated circuit form, which lead to the rise of companies like Intel and Mostek, and then there was almost a decade when core memories and semiconductor memories have coexisted, during a sharp decline of the former.