After the memory is built, ROMs of the PROM variety are written. Applications for PROM processors include mobile phones, gaming systems, RFID identifiers, medical equipment, and other electrical devices. They offer an easy way to configure electrical gadgets.

PROMs that are standard can only be set once. This is due to the fact that PROM circuits are created using a number of capacitors. By igniting fuses, which is an irrevocable procedure, the microprocessor is encoded. In contrast to melted fuses, which are read as zeros, open fuses are read as ones. A binary sequence of ones and zeros is etched on the semiconductor by igniting particular explosives. The software that was run on the Memory is represented by this design.

Although PROM cannot be deleted, two different variants of PROM have been created that can. EPROM, or Erasable Programmable Read-Only Memory, is one variety. Strong UV radiation can be used to delete the floating-gate semiconductors used in this form of memory. Electrically Erasable Programmable Read-Only Memory, or EEPROM, is the alternative variety. Flash memory uses EEPROM, which can be wiped with an electrical charge.