There are several places on a computer that we can store data on. The hard disk is the main storage device used to store all necessary data such as OS files, applications, music, videos, etc. Besides the hard drive, we also have it μνήμη RAM, ROM etc. But what is the difference between RAM and ROM?
What is Random Access Memory (RAM)?
After the hard drive or SSD, RAM is the largest storage medium on the computer hardware. RAM is used to store the programs and data the CPU uses in real time. Data in RAM can be read, written, and deleted as many times as we want.
RAM is a "volatile memory" that means the data stored there disappears at the moment the power supply stops. This is one of the reasons why we can not use RAM for permanent storage, although it is much faster than traditional hard drives.
All the modern operating systems we use have built-in ways to address the volatility of RAM. All tasks that are performed are continuously stored on the hard disk to avoid situations where unexpected shutdown of the system would result in data loss.
Types of RAM
SRAM (Static RAM): It stores each data bit using a cell with six transistors. SRAM is much faster than DRAM but more costly.
DRAM (Dynamic RAM): Stores each data bit, using a pair of transistors and capacitor, which constitute a DRAM
What is ROM (Read-Only Memory)?
Another remarkable type of memory on the computer is the ROM. As the name implies, the data in the memory can only be read by the computer. So why is this memory used?
ROM is a non-volatile memory. It does not lose its data even if the power supply has been removed. The ROM is used to store the firmware for the hardware which gets almost no updates, for example the BIOS.
Data in the traditional form of ROM is linked to it, ie past at the time of construction. Over time, this memory has been developed to support data deletion and rewriting, although it can not achieve the performance level of a RAM chipset.
Types of ROM
ROM Mask: In this type of ROM the data is written during the construction of the memory chip.
PROM (Programmable Read-Only Memory): The data is written after the memory chip has been created. It is non-volatile.
EPROM (Erasable Programmable Read-Only Memory): Data from this non-volatile memory chip can be deleted by exposure to high intensity ultraviolet radiation.
EEPROM (Electrically Erasable Programmable Read-Only Memory): Data from this non-volatile memory chip can be erased electrically using electron emission (tunneling Fowler-Nordheim). Modern EEPROMs are quite efficient in terms of read and write capabilities.
Optical storage media such as the CD-ROM is also a read-only memory format.
RAM vs ROM: What is the difference between RAM and ROM?
Both memories have their advantages and disadvantages. ROM is cheap and can hold data permanently but has its limitations. On the other hand, RAM is quite useful, but it costs more.
The ROM is more useful than you think. The flash memory we find on removable storage media, such as SSD drives, USB drives, SD cards, etc., is an advanced application of EEPROM memory type. The derivative provides a faster storage solution than traditional hard drives.