Read-only memory (ROM) is a type of non-volatile memory that is used in computers and other electronic devices to store data that is not meant to be changed or modified. There are several popular models of ROM that are commonly used in various applications. In this article, we will explore some of the most popular models of ROM and their features.

1. Mask ROM (MROM): Mask ROM, also known as MROM, is a type of ROM that is programmed during the manufacturing process. The data in a mask ROM is permanently stored and cannot be changed or modified. This type of ROM is commonly used in devices where the data does not need to be updated frequently, such as in video game cartridges or firmware for electronic devices.

2. Programmable ROM (PROM): Programmable ROM, or PROM, is a type of ROM that can be programmed by the user after it has been manufactured. PROMs are typically programmed using a special device called a PROM programmer, which burns the data into the ROM using electrical signals. Once programmed, the data in a PROM is permanent and cannot be changed. PROMs are commonly used in applications where the data needs to be customized for a specific purpose, such as in embedded systems or industrial control systems.

3. Erasable Programmable ROM (EPROM): Erasable Programmable ROM, or EPROM, is a type of ROM that can be programmed and erased multiple times. EPROMs use a special type of memory cell that can be erased using ultraviolet light. To program an EPROM, the data is written to the memory cells using electrical signals. When the data needs to be erased, the EPROM is exposed to ultraviolet light, which resets the memory cells to their original state. EPROMs are commonly used in applications where the data needs to be updated periodically, such as in BIOS chips for computers or firmware for electronic devices.

4. Electrically Erasable Programmable ROM (EEPROM): Electrically Erasable Programmable ROM, or EEPROM, is a type of ROM that can be programmed and erased electronically. EEPROMs use a special type of memory cell that can be erased using electrical signals. To program an EEPROM, the data is written to the memory cells using electrical signals. When the data needs to be erased, the EEPROM can be reset using electrical signals. EEPROMs are commonly used in applications where the data needs to be updated frequently, such as in USB flash drives or memory cards.

5. Flash Memory: Flash memory is a type of non-volatile memory that is commonly used in electronic devices such as smartphones, tablets, and digital cameras. Flash memory is similar to EEPROM in that it can be programmed and erased electronically, but it is typically faster and more durable than traditional EEPROM. Flash memory is commonly used in applications where high-speed data access is required, such as in solid-state drives (SSDs) or memory cards.

In conclusion, there are several popular models of ROM that are commonly used in various applications. Each type of ROM has its own unique features and advantages, making them suitable for different types of applications. Whether you need a ROM that can be programmed once, multiple times, or electronically, there is a model of ROM that will meet your needs.