PROM vs. EPROM — What's the Difference?
By Tayyaba Rehman & Urooj Arif — Updated on April 26, 2024
PROM (Programmable Read-Only Memory) is a type of non-volatile storage that can be programmed once; whereas EPROM (Erasable Programmable Read-Only Memory) can be erased and reprogrammed using ultraviolet light.
Difference Between PROM and EPROM
Table of Contents
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Key Differences
PROM is permanently programmed by the manufacturer or by the user using a special device; while EPROM allows the user to erase its contents using ultraviolet light and then reprogram it.
Once programmed, the data stored in PROM cannot be modified or erased; on the other hand, EPROM provides flexibility with data storage that can be erased and reprogrammed.
PROM is typically used in applications where data does not need to change; whereas EPROM is suitable for experimental or developmental work where data may need frequent updating.
The programming process for PROM involves burning a fuse or creating an open circuit, which makes the data permanent; meanwhile, EPROM uses a charge trapping method to store data, which can be cleared by exposing it to ultraviolet light.
PROM devices are generally cheaper to produce than EPROMs due to their simpler design; however, EPROMs offer a more versatile solution for applications requiring data changes.
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Comparison Chart
Programmability
Programmable once
Erasable and reprogrammable multiple times
Data Modification
Data cannot be modified or erased
Data can be erased using ultraviolet light
Usage
Used where data permanence is needed
Used in developmental processes
Cost
Generally cheaper due to simpler design
More costly due to reusability
Programming Method
Burns fuses to store data permanently
Uses charge trapping, erasable by UV light
Compare with Definitions
Prom
Used where data permanence is crucial.
PROMs are used in applications like embedded systems.
Eprom
A type of memory that can be erased and reprogrammed using ultraviolet light.
EPROMs are often used in R&D for testing new code.
Prom
A type of non-volatile memory that is programmable once.
The BIOS of older computers was often stored on a PROM chip.
Eprom
Data can be updated or corrected as needed.
If a bug is found in the software, the EPROM can be erased and reprogrammed.
Prom
Cheaper alternative for permanent data storage.
For cost-effective solutions, PROMs are preferred in certain electronics.
Eprom
Requires special equipment for erasing and reprogramming.
UV light is needed to erase the data stored in an EPROM.
Prom
Involves permanently burning data into the memory.
Once data is written on a PROM, it cannot be altered.
Eprom
More flexible than PROM for development purposes.
EPROMs are valuable in iterative development environments.
Prom
Ideal for mass-produced hardware products.
PROM chips are often found in household appliances.
Eprom
Initially more expensive due to reusability features.
Despite their higher cost, EPROMs are economical over multiple uses.
Prom
A promenade dance, commonly called a prom, is a dance party for high school students. It may be offered in semi-formal black tie or informal suit for boys, and evening gowns for girls.
Eprom
A programmable ROM that can be erased by exposure to ultraviolet light and then reprogrammed.
Prom
A kind of read-only memory whose contents can be set after manufacture, but only once.
Eprom
(computer science) a read-only memory chip that can be erased by ultraviolet light and programmed again with new data
Prom
A formal dance held for a high-school or college class typically at or near the end of the academic year.
Prom
(British) A promenade concert.
Prom
A promenade.
Prom
(US) A formal ball held at a high school or college on special occasions; e.g,. near the end of the academic year.
Would you like to be my prom date?
Prom
A formal ball held for a school class toward the end of the academic year
Common Curiosities
Can EPROM be used multiple times?
Yes, EPROM can be erased and reprogrammed multiple times.
What is PROM used for?
PROM is used for storing data that does not need to be changed once programmed.
How is data stored on an EPROM?
Data is stored using a charge trapping method that can be erased by exposing the chip to ultraviolet light.
What makes EPROM different from PROM?
EPROM can be erased and reprogrammed, unlike PROM which can only be programmed once.
How do you erase an EPROM?
By exposing it to ultraviolet light.
What is the typical use case for PROM?
PROM is typically used in applications like firmware where the data does not need to change.
Can PROM be erased?
No, once PROM is programmed, the data is permanent and cannot be erased.
What is the typical use case for EPROM?
EPROM is typically used in experimental and development settings where data may frequently change.
Are there alternatives to EPROM that do not require UV light?
Yes, EEPROM is an alternative that can be erased electronically without UV light.
Is EPROM more expensive than PROM?
Yes, EPROM tends to be more expensive due to its reusability.
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Written by
Tayyaba RehmanTayyaba Rehman is a distinguished writer, currently serving as a primary contributor to askdifference.com. As a researcher in semantics and etymology, Tayyaba's passion for the complexity of languages and their distinctions has found a perfect home on the platform. Tayyaba delves into the intricacies of language, distinguishing between commonly confused words and phrases, thereby providing clarity for readers worldwide.
Co-written by
Urooj ArifUrooj is a skilled content writer at Ask Difference, known for her exceptional ability to simplify complex topics into engaging and informative content. With a passion for research and a flair for clear, concise writing, she consistently delivers articles that resonate with our diverse audience.
