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Read Only Memory (ROM)

Last updated date: 17th Apr 2024
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Role of ROM in Computers

Read-only memory (ROM) is a data storage device used in personal computers (PCs) and other electronic devices to store information securely. It houses programs or software instructions and includes the programming required to start a computer, which is required for boot-up. It also conducts significant input/output duties. The alteration of this sort of memory, known as "firmware," has been a source of design concern throughout the growth of the contemporary computer.

Because ROM is read-only memory, it can't be modified; it's also permanent and non-volatile, which means it keeps its data even if the power is turned off. Random-access memory (RAM), on the other hand, is volatile; when power is turned off, it is gone. The phrase "non-volatile memory," which is comparable, can be applied here. In its long-term state, ROM in computer is "stateful," whereas RAM is "stateless."

ROM in Computer has the Following Characteristics:

  • Non-volatile memory is referred to as ROM.

  • The information saved in ROM is irreversible.

  • We can only read the information and applications stored on it.

  • In binary format, information and applications are stored on ROM.

  • It's utilized throughout the computer's boot-up procedure.

Types of ROM

They are four types of ROM in the computer: 

  • MROM (Masked read-only memory)

  • PROM (Programmable read-only memory)

  • EPROM (Erasable programmable read-only memory)

  • EEPROM (Electrically erasable programmable read-only memory)

Now we'll Go Through Different Types of ROM One by One:

  • MROM (Masked Read-Only Memory): MROM: Integrated circuits are found in traditional or "mask-programmed" ROM chips. A current is sent along a certain input-output channel on an MROM chip, which is specified by the position of fuses among the chip's rows and columns. Because the electricity can only go down a fuse-enabled channel, it can only return via the manufacturer's chosen output. Because rewiring is impossible, there is no method to reprogram these sorts of ROM chips. While creating a template for an original MROM chip is time-consuming, using an existing template may save a lot of money.

  • PROM (Programmable Read-Only Memory): PROM: Programmable ROM, or PROM, is a blank version of ROM that you may buy and programme once with the aid of a programmer. A blank PROM chip permits current to flow in all conceivable directions; the programmer selects a path for the current by "burning out" undesirable fuses with a high voltage. PROMs are more sensitive to damage than standard ROMs since static electricity might cause the same effect by mistake.

  • EPROM (Erasable Programmable Read-Only Memory):EPROMs are Erasable Programmable ROM chips that can be written and rewritten several times. A quartz window allows a customised EPROM programmer to emit a specified frequency of ultraviolet light through the chip. This light burns off all of the EPROM's small charges, reopening its circuits. After this exposure, the chip is basically rendered blank, and you may reprogram it using the same procedure as a PROM. EPROM chips do wear down over time, however, they often have a lifetime of over 1000 erasures.

  • EEPROM (Electrically Erasable Programmable Read-Only Memory): Apply localized electrical fields to erase and rewrite data on an Electrically Erasable Programmable ROM chip to alter it. In comparison to other forms of ROM, EEPROMs provide a number of benefits. Unlike earlier versions, EEPROM may be rewritten without special equipment, without removing it from the hardware, and in precise increments. To make a single change, you don't have to erase and rewrite everything.

Benefits of ROM in the Computer:

  • It is less expensive than RAM and is non-volatile.

  • When compared to RAM, it is more dependable.

  • In comparison to RAM, its circuit is simple.

  • Because it is static, there is no need to refresh it.

  • It's simple to put to the test.

ROM Stands for in Computer Drawbacks Include:

  • Because it is a read-only memory, it cannot be changed.

  • When compared to different types of  ROM and RAM, it is slower.

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Use for Data Storage

Because ROM full form in the computer (at least in hard-wired mask form) cannot be edited, it's only good for storing data that won't need to be changed throughout the device's lifetime. To that goal, look-up tables for the evaluation of mathematical and logical functions have been stored in ROM in many computers (for example, a floating-point unit might tabulate the sine function in order to facilitate faster computation). This was particularly useful when CPUs were sluggish and ROM was inexpensive in comparison to different types of rom and ram.

Early personal computers' display adapters, for example, held tables of bitmapped typeface characters in ROM. This generally indicated that the typeface used for text display could not be altered interactively. Both the CGA and MDA adapters that came with the IBM PC XT was like this.


So, you can see that storing such small quantities of data has almost entirely vanished. NAND Flash, on the other hand, has taken on a new function as mass storage or secondary storage media for files. A ROM device with specific software, or a file containing software to be loaded in EEPROM or Flash Memory. 

FAQs on Read Only Memory (ROM)

1. What is the full form of ROM?

The full form of ROM is read-only memory

2. What is the read-only memory's purpose?

Read-Only Memory (ROM) is a data storing technology used during devices such as computers. The most fundamental code required to start a computer is stored in ROM, which is also known as the Basic Input/Output System (BIOS).

3. What is ROM stands for in a computer?

Read-Only Memory is abbreviated as ROM. It's a term used to describe computer memory chips that store either permanent or semi-permanent data. ROM, unlike RAM, is non-volatile; the contents in ROM will not be erased even if your computer is turned off. Almost all computers have a little bit of ROM that contains the boot firmware.