ROM: (Read only memory) and PROM: (Programmable read only memory)

 ROM: (Read only memory)

• ROM is a read only memory.
• We can not write anything in it.
• In this we can use diode, MOS to store the information.
• Decoder is used to select the address lines
• OE signal is used to enable the output.

PROM: (Programmable read only memory)

• PROM is a programmable ROM
• It is used for permanent storage purpose
• Once we write something in it then we cannot change it. i.e. it become permanent
• We can use diode along with fusible link in series with it to store the information
• We can burns the fuse according to the information stored in it.