difference between ram and rom
Random Access Memory (RAM) is used to store the programs and data being used by the CPU in real-time. The data on the random access memory can be read, written, and erased any number of times. RAM is a hardware element where the data being currently used is stored. It is a volatile memory. Types of RAM:
- Static RAM, or (SRAM) which stores a bit of data using the state of a six transistor memory cell.
- Dynamic RAM, or (DRAM) which stores a bit data using a pair of transistor and capacitor which constitute a DRAM memory cell.
Read Only Memory (ROM) is a type of memory where the data has been prerecorded. Data stored in ROM is retained even after the computer is turned off ie, non-volatile. Types of ROM:
- Programmable ROM, where the data is written after the memory chip has been created. It is non-volatile.
- Erasable Programmable ROM, where the data on this non-volatile memory chip can be erased by exposing it to high-intensity UV light.
- Electrically Erasable Programmable ROM, where the data on this non-volatile memory chip can be electrically erased using field electron emission.
- Mask ROM, in which the data is written during the manufacturing of the memory chip.
The following table differentiates ROM and RAM:
| Difference | RAM | ROM |
|---|---|---|
| Data retention | RAM is a volatile memory which could store the data as long as the power is supplied. | ROM is a non-volatile memory which could retain the data even when power is turned off. |
| Working type | Data stored in RAM can be retrieved and altered. | Data stored in ROM can only be read. |
| Use | Used to store the data that has to be currently processed by CPU temporarily. | It stores the instructions required during bootstrap of the computer. |
| Speed | It is a high-speed memory. | It is much slower than the RAM. |
| CPU Interaction | The CPU can access the data stored on it. | The CPU can not access the data stored on it unless the data is stored in RAM. |
| Size and Capacity | Large size with higher capacity. | Small size with less capacity. |
| Used as/in | CPU Cache, Primary memory. | Firmware, Micro-controllers |
| Accessibility | The data stored is easily accessible | The data stored is not as easily accessible as in RAM |
| Cost | Costlier | cheaper than RAM. |
