A Programmable Read-Only Memory (PROM) is a type of digital memory where the contents can be changed once after the device has been manufactured
. It is a form of non-volatile memory, meaning the data is permanent and cannot be changed
. PROMs are used in various digital electronic devices to store permanent data, such as low-level programs like firmware or microcode
. The key difference between a standard ROM and a PROM is that the data is written into a ROM during manufacture, while with a PROM, the data is programmed into them after manufacture
. Some characteristics of PROM include:
- Programming : PROMs can be programmed only once, and the programming is done electrically by the user
- Memory : PROMs are non-volatile, meaning the data is permanent and cannot be erased or deleted
- Usage : PROMs are used for storage when their content is not expected to change, but in many applications, they have given way to EPROMs and EEPROMs, which can be reprogrammed
PROMs were invented in 1956 by Wen Tsing Chow, working for the Arma Division of the American Bosch Arma Corporation in Garden City, New York
. They were created to fulfill the requirement of a group of ROMs that may contain a selected memory
