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Read-only memory

(also ROM)

Read-only memory definition

Read-only memory is a type of non-volatile memory used in computers and electronic devices. As the name suggests, data stored in ROM is read-only and cannot be easily modified or rewritten. It remains intact even when the device is turned off.

ROM's main purpose is to store firmware — software that is permanently programmed into the memory. When a device is switched on, it reads the instructions from the ROM to boot up and function properly.

See also: random access memory

History of read-only memory

ROMs were introduced in the early days of computer technology. Initially, they were hardwired and required a complete redesign to change their contents. Later, programmable ROMs were developed, allowing users to write data on them once. Erasable programmable ROMs and electrically Erasable programmable ROMs expanded the flexibility of read-only memory even further by letting users erase and reprogram memory multiple times.

Read-only memory advantages

  • Data is saved even when power is turned off.
  • ROM is not easily rewritten, so it’s a stable storage solution for crucial system instructions.
  • It’s less susceptible to data corruption compared to volatile memories.

Read-only memory disadvantages

  • Traditional ROMs cannot be modified — it makes updates and corrections challenging.
  • Producing ROM, especially in custom configurations, can be expensive.
  • ROM is typically slower than RAM when it comes to data access speeds.