RAM: A type of memory made of silicon material, where data can be stored and deleted after processing, is called RAM. The stored data is deleted as soon as the computer is switched off. That is why it is volatile. It is called RAM (Random Access Memory) because it takes the same time to access information from any of the thousands of computer memory cells. First home PC also used 64KB RAM. Modern computers now use at least 64MB of RAM. RAM chips come in different sizes (1 MB to 64 GB).
Features:
1. The computer uses this RAM for all kinds of tasks that the user pays for.
2. Data is usually stored here based on the electrical charger.
3. All data is deleted when the computer is switched off. So it is called volatile memory.
4. RAM data can be changed as needed.
* There are two types of RAM; For example-
1. Static RAM.
2. Dynamic RAM.
Static RAM: This RAM is used in personal computers based on bipolar semiconductors. Data is stored as long as the computer is connected to power. It does not need to be refreshed. SRAM is faster and more expensive than DRAM. It has low storage capacity but high performance. SRAM is again of two types; For example - Asynchronous SRAM and Burst SRAM.
Dynamic RAM: This RAM is made of MOSFET transistor gates and needs to be recharged at regular intervals. Hence it is slower than SRAM. Again this RAM is cheaper than SRAM. Dynamic RAM does not need to be refreshed. ;Most of the RAM used in computers is made up of it.
ROM: This memory is read only memory. Based on this memory circuit. This memory uses logic gates to store instructions. As a result, the information stored by this memory is not deleted (even when the computer is switched off) so it is called non-volatile memory. ROM - Its contents cannot be changed, only read. No new instructions can be stored in this memory. When the ROM is created, the manufacturer stores the contents in the ROM.
Features:
1. As the information stored by this memory cannot be erased, it is called non-volatile memory.
2. Its data is read-only.
3. The necessary information is permanently stored in it.
4. Larger in size than RAM.
5. It takes more time than RAM while receiving data.
*This memory tests RAM performance.
*This is used to test input devices (e.g. keyboard efficiency).
*This ROM is also useful for testing output devices.
*Operating system is loaded in this ROM.
Types of ROM: ROM is divided into four types, they are-
(i) PROM (Programmable Read Only Memory): This type of ROM chips can be programmed and hence the data cannot be changed. It is a passive memory.
(ii) EPROM (Erasable Programmable Read Only Memory): In this type of memory, new data or records can be filled with the help of programs and any data can also be deleted. That's why this ROM is named EPROM.
(iii) EEPROM (Electrically Erasable Read Only Memory): In this type of ROM, data can be erased and reprogrammed with the help of electrical pulses.
(iv) UVPROM - Ultraviolet Programmable Read Only Memory.
