Read-Only Memory

Also found in: Dictionary, Thesaurus, Medical, Legal, Financial, Acronyms, Wikipedia.

read-only memory

[′rēd ¦ōn·lē ′mem·rē]
(computer science)
A device for storing data in permanent, or nonerasable, form; usually a static electronic or magnetic device allowing extremely rapid access to data. Abbreviated ROM. Also known as read-only storage.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.

Read-Only Memory

(ROM) A type of data storage device which is manufactured with fixed contents. In its most general sense, the term might be used for any storage system whose contents cannot be altered, such as a gramophone record or a printed book; however, the term is most often applied to semiconductor integrated circuit memories, of which there are several types, and CD-ROM.

ROM is inherently non-volatile storage - it retains its contents even when the power is switched off, in contrast to RAM.

ROM is often used to hold programs for embedded systems since these usually have a fixed purpose. ROM is also used for storage of the lowest level bootstrap software (firmware) in a computer.

See also Programmable Read-Only Memory.
This article is provided by FOLDOC - Free Online Dictionary of Computing (


(1) In an Android phone, a file for firmware updating. See Android ROM.

(2) (Read Only Memory) A memory chip that permanently stores instructions and data. Also known as "mask ROM," its content is created in the last masking stage of the chip manufacturing process, and it cannot be changed. Stand-alone ROM chips and ROM banks in microcontroller chips are used to hold control routines for myriad applications. ROMs were also widely used to hold the BIOS in early PCs as well as plug-in cartridges for video games.

Although EPROMs, EEPROMs, and particularly flash memory, are the kinds of non-volatile storage one hears about more often, ROM is a mature, inexpensive technology that is easy to integrate into the design of any CMOS chip.

ROMs Are Secure
Unlike flash memory, which can be updated, the data in ROM chips cannot be tampered with. If encryption keys and other security codes are stored in a ROM, they cannot be altered unless the chip is physically replaced (see secure boot). See memory types, RAM, EEPROM and flash memory.

ROMs Are Everywhere
Cartridges that contain nothing more than a ROM chip are used to hold games and educational programs. The yellow ROM cartridge in this image (bottom right) contains a program for the LeapPad Learning System for preschoolers.
Copyright © 1981-2019 by The Computer Language Company Inc. All Rights reserved. THIS DEFINITION IS FOR PERSONAL USE ONLY. All other reproduction is strictly prohibited without permission from the publisher.
References in periodicals archive ?
Standing for Digital Versatile Disk Read-Only Memory, DVD-ROM uses discs similar to CD-ROM discs, but they typically hold seven to eight times more data.
But Oki Electric officials said the firm plans to ask Fujitsu to pay the damages, saying the malfunction of its ATMs resulted from Fujitsu-made read-only memory chips (ROMs) it had bought to install in its ATMs.
Atmel Smartcard IC Ltd UK will make read-only memory (ROM) for contact and high-end contactless cards at an East Kilbride fab bought from Motorola in April.