What is ROM and its types

ROM

Read-only memory (ROM) is a type of permanent storage medium that is used in computers and some other electronic devices. It contains the information on boot-up and it performs major I/O tasks. This type of memory is usually referred to as “firmware”.

Types of ROM

• PROM
• EPROM
• EEPROM
• Flash

PROM

Programmable read-only memory (PROM) is a type of (ROM) and it can be modified at once by a user. It cannot be rewritten. Data or programs can be written on ROM using a special machine called a PROM programmer. This machine uses electric current and supplies to particular cells of ROM and blows its fuse. This is called burning the PROM. This process is more effective and error-free.

EPROM

EPROM (erasable programmable read-only memory) is the type of ROM that can be erasable after writing data on it. To delete data of this kind of ROM we place the memory chip in shining ultraviolet light. Sunlight contains ultraviolet light and this ROM can be erased by exposing sunlight. It is effective and rewritable. It is more expensive than PROM.

EEPROM

EEPROM (electrically erasable programmable read-only memory) is the type of ROM that can easily be modified by the user. It can repeatedly be erased and reprogrammed by applying an electrical voltage. EEPROM is consist of arrays of transistors. It can easily ease and program by some special electrical signals. At its early stage, it supports single-byte operation which made him slower, but now it supports multi-byte page operation. An EEPROM has decreased its life after every time it is erased and reprogrammed and its life cycle is an important consideration for its design.

Flash

It is also a type of non-volatile memory. Data is written on it at the byte level and erased at the block level. It keeps data for a long period of time whether a flash-equipped device is powered off or on. Flash memory is mainly used for data transfer and data storage in devices, both for individual and industrial use. It is used widely used in storage devices, data center servers, networking devices also in normal consumer devices. For example SD cards, digital cameras, USB flash drives, mobile phones, and tablets. It is also used in computers to increase performance and speed to analyze a large set of data.