MAIN MEMORY (COMPUTING): COMPONENTS, TYPES, FUNCTIONS - TECHNOLOGY - 2025

The main memory is the part of the computer where the software applications, operating system and other information are stored so that the central processing unit (CPU) has a shortcut and quick when required to perform tasks.

It is described as the internal memory of the computer. The word "main" is used to distinguish it from peripheral storage devices. It is also called random access memory (RAM), since the CPU can immediately go to any sector of memory without having to do this process as a sequence.

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RAM is one of the fastest types of memory. Allows data to be read and written. However, turning off the computer purges everything that is contained in it.

The computer can only handle the data that is in main memory. Therefore, every program that is run and every file that is accessed must be copied from a storage device to main memory.

Components

Memory modules can be of various sizes and with various pin configurations.

SIMM

Corresponds to the acronym for "Single Online Memory Module". A SIMM is a small sheet with a large number of memory chips. SIMMs use a 32-bit bus.

The original SIMMs had 30 pins or connectors, which are metal contacts that connect to the motherboard. However, the new SIMM chips have 72 pins.

Newer processors require a 64-bit memory bus, so it is better to use DIMMs.

DIMM

It stands for 'Dual Inline Memory Module'. A DIMM is a small board that contains memory chips. It uses a 64-bit bus to memory, whereas a single in-line memory module (SIMM) only has a 32-bit path.

This allows the DIMMs to transfer more data at a time. Because DIMMs have faster data transfer capabilities than SIMMs, they have practically replaced them completely.

DIMMs come in 168-pin configurations, but some DIMMs have up to 240 pins.

SO-DIMM

It stands for "Small Enclosure Dual Inline Memory Module." Most desktop computers have plenty of room for RAM chips, so the size of the memory modules is not a concern.

However, with the advent of laptop computers the size of memory modules became very important. This is why SO-DIMMs were conceived

The size of an SO-DIMM is only 50% that of a DIMM. This makes it easy to be flexible when designing memories for this type of computer.

SO-DIMMs initially had 72 connectors, and data transfers were 32-bit. However, today's SO-DIMMs typically have 144 pins, making it possible to perform the same 64-bit transfers as a full-size DIMM.

Types

Dynamic Random Access Memory (DRAM)

It is the most used type of main memory in a computer. The data bits are stored in a memory box, which consists of a small capacitor and a transistor.

The capacitor can be in a charged or discharged state. These two states are used to symbolize the two values ​​of a bit, which are zero and one.

However, the electrical charge on the capacitors is slowly being lost. To solve this, the DRAM needs to have an external circuit to refresh the memory, repeatedly copying the information contained in the capacitors to restore their initial charge.

Thus, the DRAM is constantly replenishing whatever data is stored in memory. It updates the information by sending millions of pulses per second to the memory cell. This update process is the defining characteristic of dynamic random access memory.

DRAM is unstable memory, because the information it contains vanishes immediately when power is cut off.

Static Random Access Memory (SRAM)

It is a semiconductor memory that uses a bistable enclave circuit (flip-flop) to store each bit. It is commonly used in embedded devices as a memory source. It is faster and more expensive than DRAM.

The information stored in the SRAM does not need to be continuously renewed, in this memory the data is fixed as a “static image”, until it is erased when the power is disconnected, or is written on it.

Consequently, SRAM when not in use is more efficient and less dense in energy consumption. In this sense, it is a better option than DRAM for certain uses, such as the caches located in the CPUs.

On the other hand, the density of DRAM makes it a better alternative for main memory.

Features

Main memory provides eventual storage for information required by the computer. Instead of having to search the hard drive whenever data is required, commonly used information is temporarily stored in RAM, making it faster to find.

When the computer shuts down, all the data in RAM is erased, making room for new data when the computer starts up again.

When the microprocessor finishes executing a set of instructions and is about to perform the next task, it gets the data it needs from RAM.

Computer speed

Having an adequate amount of RAM has a direct result in the speed of the computer.

If a system does not have enough main memory to run its applications, it will have to rely on the operating system to create additional memory resources on the hard disk, by "exchanging" data.

However, when the processor has to get data from the hard drive instead of RAM, it slows down the performance of the computer.

Main uses

- Storage of a copy of the main systems that control the general operation of the computer. This copy is loaded into RAM when the computer is turned on and remains there as long as the computer is on.

- Temporary storage of a copy of the instructions of an application, which the central processing unit (CPU) must retrieve for interpretation and execution.

- Temporary storage of information that has been entered from an input device. This is until the application requests that this data be transferred to the CPU for processing.

- Temporary storage of information that has occurred as a result of processing, until the application requests that this data be used again in further processing, or transferred to an output device or a storage device.

References

1. John Landers (2019). What is Main Memory in a Computer? Taken from: techwalla.com.
2. Vangie Beal (2019). Main memory. Webopedia. Taken from: webopedia.com.
3. Blurtit (2019). What Are The Functions Of Main Memory (RAM)? Taken from: technology.blurtit.com.
4. Techterms (2019). Memory Module. Taken from: techterms.com.
5. Wikipedia, the free encyclopedia (2019). Computer memory. Taken from: en.wikipedia.org.