We explain what RAM memory is, what it is for and how it differs from ROM memory.
What is RAM memory?
In computing, RAM memory (acronym for Random Access Memorythat is, “Random Access Memory” in English) is a type of operating memory of computers and computer systems, where most of the software is executed, from the operating system itself to application software and other similar programs.
The term “random” refers to allows recording or recovering information without the need for sequential order (as happens, however, in ROM memory or Read-Only Memorythat is, “Read Only Memory” in English). RAM memory is free access memory, which the system always has on hand, which can be accessed quickly and easily.
On the other hand, RAM It is a form of temporary memory in the short term, which when you turn off or restart the system it is blank again. That is why, when you turn on the computer, the basic operating modules inscribed in ROM (such as POST or BIOS) check the RAM memory to ensure that it is operational and the software necessary to start can be loaded into it. the system.
In most computers, this type of memory is not usually soldered to the motherboard (as it is, for example, in video game consoles), but is found on removable and replaceable printed circuit boards, known as RAM modules. Each module has a number of memory chips and a specific capacity, currently measured in megabytes (1024 kilobytes) or gigabytes (1024 megabytes).
See also: Cache memory
RAM memory characteristics
RAM memory is characterized by the following:
- It is free access. The system accesses it randomly, that is, without an established sequential order and in the fastest and most agile way possible.
- Works short term. Once the system is restarted or turned off, the RAM remains blank so it can be used again in the next cycle.
- Determines the simultaneous computing capacity. Since it is where your computer programs will run, the amount of RAM in your system determines how many things you can do at the same time.
- It is bidirectional. Data can be entered or “written” into RAM memory, as well as extracted or “read”, unlike other types of memory, such as ROM.
- Can be fixed or expandable. In some systems, the amount of RAM is predetermined and cannot be increased, while others allow new modules to be added to increase system memory.
What is RAM used for?
RAM is the operating memory of the computer system, that is, it is where the various programs in use run and remain active, from the operating system itself to the work applications that we use.
That's why By keeping too many applications active simultaneously, the system's RAM capacity decreases and this can interfere with the computing speed of the system. The more RAM a computer system has, the more activities it can carry out simultaneously.
Likewise, a highly specialized system may require a greater amount of RAM than a personal computer, or may use specific types of RAM that are much more efficient.
Types of RAM
There are two ways to classify RAM memory.
Depending on its technology and the function it performs in the system, RAM memory can be:
SRAM memory
His name is an acronym for Static Random Access Memory (Static Random Access Memory) and it is a type of RAM based on semiconductors and capable of maintaining data without the need for cooling circuits.
It is not a type of memory expandable by the user, but is usually predetermined as “cache” memory, that is, dedicated to the system processor.
DRAM memory
His name is an acronym for Dynamic Random Access Memory (Dynamic Random Access Memory), and is a type of RAM that bases its technology on capacitors, which progressively lose charge require a cooling circuit that checks their charge and replenishes it.
It was invented at the end of 1960 and is the most used type currently, as it allows the creation of high-speed modules, so the user can normally increase it in their system.
Depending on the type and number of operations allowed by the system, RAM can be:
SDR memory
His name is an acronym for Single Data Rate (single data rate), since it is a RAM memory that, throughout a computing cycle, is capable of processing a single read or write operation. This means that it can be read or written to, but not both simultaneously.
DDR memory
His name is an acronym for Double Data Rate (double data rate), since it is a RAM memory that, throughout a computing cycle, is capable of processing two read or write operations. This means that it can be read and written to in the same cycle, for which the memory is activated twice at a time.
DDR memory It is the most used in commercial computers today and is the basis for the creation of many other forms of new RAM, such as DDR2, DDR3, DDR4 or DDR5, each faster than the last.
Differences between RAM and ROM memory
The differences between RAM and ROM have to do with the type of operations that each allows, and can be summarized as follows:
| RAM memory | ROM memory |
|---|---|
| It is a read and write memory, which allows the system to enter and extract information. | It is a read-only memory, that is, it only allows data to be extracted. |
| It is always open to intervention and information recovery, so it is accessed randomly, without an established order. | It is closed to intervention (except under specific conditions such as starting the computer) and according to a specific sequence. |
| It is used to execute all types of programs, from the operating system to application software. | It is not used to execute programs, but rather the fundamental and unmodifiable instructions of the system, which are read in ROM and executed in RAM, such as the firmware. |
| It is usually upgradeable and is arranged in separate modules on the computer's motherboard. | It is not addable and is inscribed on a specific microchip on the computer's motherboard. |
| It can be of several types: SRAM, DRAM, DDR or SDR, among others. | It can be of four types: Mask ROM, PROM, EEPROM and EPROM, depending on whether it can be programmed and erased electronically or not. |
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References
- Durán Rodríguez, L. (2007). The big book of the internal PC. Marcombo.
- Hewlett Packard Mexico. (2021). RAM and ROM: what is the difference? https://www.hp.com/
- The Encyclopaedia Britannica. (2024). RAM (computing). https://www.britannica.com/
- Ujaldón Martínez, M. (2003). PC architecture. Science Editorial.
