Random Access Memory (RAM) and Read Only Memory (ROM) chips.

In a computer system, the main memory serves as the primary storage device. Programs and data are stored in this comparatively huge quick memory during run-time operations.

Integrated circuit technology is the major technology utilized in the main memory. There are two primary categories for the integrated circuits used in the main memory.

RAM (Random Access Memory) integrated circuit chips
ROM (Read Only Memory) integrated circuit chips

RAM integrated circuit

Static and dynamic are two more categories into which RAM integrated circuit chips can operate.

Static RAM:-

The binary data is stored by flip-flops, which are the main components of a static RAM.
Information that is saved has a volatile nature, meaning that it is only valid while the system is powered on.
Compared to dynamic RAM, static RAM is simpler to utilize and requires less time to perform read and write operations.

Dynamic RAM:-

The binary information is displayed by the dynamic RAM as applied electric charges to capacitors.
MOS transistors are used inside the chip to combine the capacitors.
Dynamic RAM offers significant store capacity on a single memory chip while using less power.
RAM chips come in different sizes and are used based on the needs of the system.
The interconnection of the chips of a 128 * 8 RAM chip is shown in the block diagram that follows.

The memory capacity of a 128 * 8 RAM chip is 128 words, or eight bits (one byte) per word. An 8-bit bidirectional data bus and a 7-bit address are needed for this.
Data can be transferred from memory to the CPU during a read operation or from the CPU to memory during a write operation thanks to the 8-bit bidirectional data bus.
The two chip select (CS) control inputs are used to enable the chip only when the CPU picks it, while the read and write inputs define the memory operation.
Three-state buffers are used in the construction of the bidirectional data bus.
Three alternative states are available for the output produced by three-state buffers: a high-impedance state, a signal equal to logic 0, or a signal equal to logic 1.

Note: The logic 1 and 0 are standard digital signals whereas the high-impedance state behaves like an open circuit, which means that the output does not carry a signal and has no logic significance.

Advantages of Random Access Memory (RAM)

Speed:

The computer can access data stored in RAM more quickly since RAM operates at a significantly higher rate than other storage media like hard drives and solid-state drives.

Flexibility:

RAM is volatile memory, which implies that it is simple to add or remove data from it.
For storing data that the computer is presently utilizing or processing, this makes it perfect.

Capacity:

The RAM's capacity may be readily increased, enabling the computer to store more information there and perform better overall.

Power Management:

RAM is the best type of memory for portable devices because it uses less energy than solid-state drives and hard drives.

Disadvantages of Random Access Memory (RAM)

Volatility:

RAM is a volatile memory, meaning that when the power is switched off, the information contained inside is gone.
This could be an issue for crucial data that must be kept safe, including unsaved work or unbacked-up files.

Capacity:

Although RAM can be expanded, its limited capacity may still leave it insufficient for some applications or tasks that demand a lot of memory.

Cost:

Upgrading a computer or device's memory might be more expensive when RAM is used instead of alternative memory types like hard drives or solid-state drives.

ROM integrated circuit

Although some memory may be built using ROM chips, RAM integrated circuit chips are the major component of main memory.
Programs and data that are stored on the computer permanently are kept in a ROM memory.
The ROM section of main memory is required not just for the permanent storage of data but also for the initial program known as a bootstrap loader.
When the power is turned on, the bootstrap loader program's main job is to get the computer software running.
ROM chips come in different sizes and are utilized based on the specifications of the system.
The chip connections in a 512 * 8 ROM chip is shown in the block diagram below.

RAM chips and ROM chips are structured similarly. But the data bus can only function in an output mode; a ROM can only read data.
Any one of the 512 bytes that are stored on the ROM chip can be specified by its 9-bit address lines.
For the unit to function, chip selects 1 and 2 must have values of 1 and 0. The data bus is considered to be in a high-impedance state otherwise.

Types of Read-Only Memory (ROM)

PROM (Programmable Read-Only Memory)
EPROM (Erasable Programmable Read Only Memory)
EEPROM (Electrically Erasable Programmable Read Only Memory)
MROM (Mask Read Only Memory)

Programmable read-only memory, or PROM:

You can program it yourself. The information and instructions within are unchangeable once coded.

Erasable Programmable Read-Only Memory, or EPROM:

It is re-programmable. You can use UV light to remove data from it. Wipe off all of the prior info to reprogram it.

EEPROM (Electrically Erasable Programmable Read-Only Memory):

No ultraviolet radiation is required to erase the data; an electric field can be used instead. Only a piece of the chip can be erased.

Mask ROM, or MROM:

A type of read-only memory called mask ROM is removed during manufacturing.
Mask ROM, like other forms of ROM, does not allow the user to alter the data that is contained within. If it could, the procedure would be challenging or delayed.

Advantages of Read Only Memory (ROM):-

Non-volatility:

Random Access Memory (ROM) is memory that does not lose data when the power is switched off.
For storing data that doesn't need to be changed, like the BIOS or firmware for other hardware devices, this makes it perfect.

Reliability:

Compared to other forms of memory, ROM data is less prone to corruption or errors since it is difficult to alter.

Power Management:

Random Access Memory (ROM) is a great memory option for portable devices since it uses less power than other memory types.

Disadvantages of Read Only Memory (ROM):-

Reduced Flexibility:

Random-Origin Memory (ROM) is read-only memory, meaning that its contents cannot be changed.
For programs or firmware that need to be updated or changed, this could be an issue.

Limited Capacity:

ROM often has a finite capacity, and updating it might be costly or challenging.

Expense:

ROM can be more expensive than other memory types, including solid-state or hard drives, which might increase the expense of upgrading a computer's or device's memory.

What are the Differences Between RAM and ROM?

Parameter	RAM	ROM
Full Form	RAM stands for Random Access Memory.	ROM stands for Read Only Memory.
Definition	RAM is a primary memory of the computer that stores those data and instructions on which the CPU is currently working.	ROM is a primary memory of the computer that stores those computer instructions and programs that do not need to be altered in future like BIOS.
Nature	RAM is a volatile memory. Which means it stores data as long as power is on.	ROM is a non-volatile memory that means it stores data permanently even when power is off.
Data Access	The CPU of the computer can read, write, or alter the data on RAM.	CPU can only read data from ROM, but it can write or change.
Usage	RAM is used to store data that CPU needs for current instruction processing.	ROM is used to store data that in needed to bootstrap the computer.
Types	There are two major types of RAM available – SRAM (Static Random Access Memory) and DRAM (Dynamic Random Access Memory).	Three types of ROM available – PROM (Programmable ROM), EPROM (Erasable PROM), and EEPROM (Electrically EPROM).
Speed	The speed of RAM is quite high.	The speed of ROM is slower than RAM.
CPU Access	CPU can access data stored on RAM directly.	Data to be copied from ROM to RAM so that CPU can access its data.
Capacity	RAM memory is large and high capacity.	ROM is generally small and of low capacity.
Used as	RAM is used as CPU Cache, Primary Memory.	ROM is used as firmware by microcontrollers.
Cost	RAM is costly.	ROM is not so expensive.