February 27, 2024
Prom full form

What is PROM full form? Also Know About ROM and SROM

PROM Full Form. In the world of technology and computers, acronyms and abbreviations are commonly used to represent complex terms. One such acronym is PROM, which stands for Programmable Read-Only Memory. In this article, we will delve into the full form of PROM, its features, applications, and its significance in the field of computing.

What Is PROM Full Form?

Prom full form

PROM, short for Programmable Read-Only Memory, is a type of memory chip used in digital electronic devices. It is a non-volatile storage medium that retains its data even when the power supply is removed. Unlike random-access memory (RAM), PROM is a type of read-only memory (ROM), meaning that the data stored in PROM cannot be modified or erased after it has been programmed.

How Does PROM Work?

PROM works by utilizing a grid of diodes, known as fuses, and their connections. Each fuse represents a bit of information, either a 0 or a 1. The programming of PROM is done during the manufacturing process. Once programmed, the information remains stored permanently, and the data cannot be altered.

To program PROM, a special device called a PROM programmer is used. The programmer applies high voltages to selected points on the chip, causing the fuses to blow or remain intact, depending on the desired binary data pattern. This programming process is irreversible, making PROM an ideal choice for storing firmware, microcode, and other fixed data.

Types of PROM

There are two main types of PROM: OTP (One-Time Programmable) PROM and UV-EPROM (Ultraviolet Erasable Programmable Read-Only Memory).

  1. OTP PROM: OTP PROM can be programmed only once during the manufacturing process. Once the data is programmed, it cannot be altered or erased. This type of PROM is cost-effective and widely used for applications that require permanent storage of data.
  2. UV-EPROM: UV-EPROM is erasable and reprogrammable. It allows the user to erase and reprogram the data multiple times using ultraviolet light. To erase the data, the UV-EPROM chip is exposed to ultraviolet light for a specified duration. After erasure, new data can be programmed using a PROM programmer.

Applications of PROM

PROM has found various applications in the field of computing and electronics. Some common applications include:

  1. Firmware Storage: PROM is commonly used to store firmware, which contains the instructions for operating electronic devices, such as routers, printers, and game consoles.
  2. Microcontrollers: PROM is used in microcontrollers to store the program instructions that control the operation of the device.
  3. Embedded Systems: PROM is used in embedded systems to store data or program code that needs to be retained even when power is lost.
  4. Security Devices: PROM is used in security devices, such as smart cards and authentication systems, to store encryption keys and other sensitive information.

Advantages of PROM

PROM offers several advantages over other types of memory:

  1. Non-Volatile: PROM retains data even when the power supply is removed, making it ideal for storing critical data that needs to be preserved.
  2. Permanent Storage: Once programmed, the data in PROM cannot be modified or erased, providing a high level of data security.
  3. Cost-Effective: PROM is relatively inexpensive compared to other types of memory, making it an economical choice for many applications.

Disadvantages of PROM

Despite its advantages, PROM also has some limitations:

  1. Limited Programmability: PROM can be programmed only once (in the case of OTP PROM) or a limited number of times (in the case of UV-EPROM), restricting its flexibility compared to other types of memory.
  2. Lack of Data Modification: Once programmed, PROM cannot be modified or updated, requiring the production of new chips if changes are needed.

What Is SROM?

Srom full form

SROM, or Simple Read-Only Memory, is another type of non-volatile memory. Unlike PROM, SROM is not programmable by the end user or during the manufacturing process. Instead, SROM comes pre-programmed from the manufacturer with fixed data. The data in SROM is typically hardwired using mask programming techniques, where the connections between memory cells are permanently set during the fabrication process. SROM is commonly used for storing small sets of fixed data or instructions that do not require modification or customization.

Key Differences Between PROM and SROM

While both PROM and SROM are types of ROM, there are several key differences between them:

  1. Programmability: PROM is programmable, allowing users to store specific data by blowing or leaving intact the fuses during the manufacturing process. In contrast, SROM is not programmable and comes pre-programmed with fixed data.
  2. Flexibility: PROM offers flexibility as the data can be customized or updated during programming. SROM, on the other hand, lacks flexibility since the data is permanently fixed and cannot be changed.
  3. Ease of Use: PROM requires a dedicated PROM programmer to set the fuses and program the desired data. SROM, being pre-programmed, does not require any additional programming steps and is ready to use out of the box.
  4. Applications: PROM is commonly used for firmware storage, microcontrollers, and embedded systems. SROM, with its fixed data, is often employed for simple instructions, look-up tables, or data that do not require modification.


PROM and ROM (Read-Only Memory) are both types of non-volatile memory, but they differ in programmability. PROM can be programmed or written after the manufacturing process, whereas ROM contains pre-recorded data that cannot be modified. PROM offers more flexibility but has limited programmability compared to ROM.

Applications of PROM and SROM

Both PROM and SROM find applications in various fields:

  • PROM is used in devices that require firmware storage, such as routers, printers, and game consoles. It is also utilized in microcontrollers to store program instructions.
  • SROM is employed in applications where fixed data or instructions are sufficient, such as small-scale electronic devices, calculators, and basic control systems.


In conclusion, PROM, which stands for Programmable Read-Only Memory, is a non-volatile memory chip used in digital electronic devices. It is programmed during the manufacturing process and retains its data permanently. PROM has various applications in firmware storage, microcontrollers, embedded systems, and security devices. While it offers advantages such as non-volatility and permanent storage, it also has limitations in terms of programmability. Understanding the full form of PROM and its features is essential for anyone working with digital electronics and computing.

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Frequently Asked Questions

Can PROM be reprogrammed after it is initially programmed?

No, once PROM is programmed, the data cannot be modified or erased. It remains permanently stored.

Is PROM more expensive than other types of memory?

No, PROM is relatively cost-effective compared to other memory technologies, making it a popular choice for many applications.

What happens if a mistake is made during PROM programming?

If a mistake occurs during PROM programming, the chip becomes unusable, as the data cannot be modified or corrected.

Can PROM chips be reused or recycled?

No, PROM chips cannot be reused or recycled due to their permanent programming. They are typically disposed of properly.

Are there any alternatives to PROM for storing data?

Yes, there are alternatives such as EEPROM (Electrically Erasable Programmable Read-Only Memory) and flash memory, which provide programmability.

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