Difference between PROM and EPROM

PROM and EPROM are the types of Read Only Memory(ROM). The primary difference between PROM and EPROM is that PROM is a read-only memory that can only be written once, while EPROM is a read/write memory that can be written and erased multiple times.

PROM

The PROM (Programmable Read Only Memory) chip is a type of memory chip that stores data permanently, just like a hard drive. PROM chips are programmed once at the factory and cannot be reprogrammed after they leave the factory.

EPROM

The EPROM (Electrically Programmable Read-Only Memory) chip was developed to overcome some of the shortcomings of PROM chips. EPROM chips have the ability to store data electrically, making them easier to reprogram than their predecessors.

The first EPROMs were introduced in 1971 and quickly gained popularity due to their lower cost than PROMs.

One downside of EPROMs compared to PROMs is that they are more responsive to electrical noise and radiation, which reduces their storage permanency. MOS transistors are an essential component in the construction of EPROMs.

Difference between PROM and EPROM

PROM	EPROM
The full form of PROM is Programmable Read Only Memory.	The full form of EPROM is Erasable Programmable Read Only Memory.
It is programmable memory.	It is erasable programmable memory.
The user can write instructions on the PROM only once.	The user can write instructions on EPROM many times.
If there is an error while writing on PROM, it becomes unusable.	If there is an error while writing on EPROM, it becomes usable.
It provides less usability as instructions are written only once.	It provides more usability as instructions are written many times.
It is the older version of EPROM.	It is the newer version of PROM.
It is more flexible.	It is less flexible.
It has a very high storage capacity.	It has low storage capacity.
It is read-only memory.	It is both read and written memory.
It is not reusable.	It is reusable.
It is cheaper than EPROM.	It is more expensive than PROM.
In PROM bipolar transistor is used.	In EPROM MOS transistor is used.
Once the PROM is processed, it cannot be reversed.	Once the EPROM is processed, it can be reversed.

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