Programmable read-only memory facts for kids

A PROM chip in a PDA

Programmable Read-Only Memory (PROM) is a special kind of computer memory. It's like a blank book where you can write information only once. Once the information is written, it stays there forever, even if the power is turned off. This is why it's called "read-only" – you can read the information, but you can't easily change it.

What is PROM?

PROM stands for Programmable Read-Only Memory. Think of it as a memory chip that comes empty from the factory. You, or a computer programmer, can then put specific instructions or data onto it. This is done using a special device called a PROM programmer.

Once the information is "burned" onto the PROM chip, it becomes permanent. This makes PROM very useful for storing important programs or settings that a device needs to start up or work correctly. For example, older video game cartridges sometimes used PROM chips to store the game's code.

How is PROM Different?

You might know about other types of computer memory, like RAM (Random Access Memory). RAM is like a whiteboard; you can write and erase things many times. PROM is different because it's more like writing with a permanent marker.

• Read-Only: The "ROM" part means the information is usually just for reading.
• Programmable: The "P" part means you can program it yourself one time.

This one-time programming makes PROM reliable for storing unchanging data.

Types of PROM

Over time, engineers found ways to make PROM chips more flexible. This led to other types of memory:

EPROM

Some PROM chips can actually be erased and rewritten! These are called EPROM, which stands for Erasable Programmable Read-Only Memory. To erase an EPROM, you have to expose it to strong ultraviolet (UV) light. This light clears all the stored information, letting you program it again. EPROMs usually have a small quartz window on top so the UV light can reach the chip inside.

EEPROM

Even more advanced chips are called EEPROM, or Electrically Erasable Programmable Read-Only Memory. The cool thing about EEPROM is that you can erase and rewrite it using electricity, right inside the computer! You don't need special UV light or a separate device. This makes EEPROM very convenient for things like storing settings on your phone or computer that might need to be updated occasionally.

Images for kids

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  Texas Instruments PROM type TBP18SA030N

See also

In Spanish: Memoria programable de solo lectura para niños