A computer, laptop, smartphone or tablet has two types of memory. The internal one is usually responsible for saving multimedia files and programs, but the operational one is working, in other words, temporary. Usually in modern devices there is a sufficient supply of both memory, but it happens that the user needs to expand it. And if in the case of the internal one you can just buy an external drive, then this will not work with the operational one.
What is it?
RAM is a temporary archive that stores data of all programs for a certain period of time during their operation. After the device is turned off, the storage is cleared. Therefore, the PC always recommends that the user save all editable data, since after shutting down unsaved changes will disappear.
Usually, when it comes to “RAM”, an archive is presented that saves all active processes and software. But sometimes this term is also called external storage devices such as disks or storage devices on magnetic tape.
In general, all types of RAM are volatile elements of the system. They store the machine code of the software, as well as input / output and intermediate materials on which the processor works.
Historical basis
Before we study the types and types of RAM, it is important to understand how it all began. The story begins already in the early 30s of the 19th century. Then Charles Babbage worked on the analytical machine. Those blocks that were supposed to maintain interval calculation results, he called "warehouses." All information about these cells was stored mechanically, in the form of an arrangement of shafts and gears between each other.
When the first generation arithmometer was created, its functionality was considered experimental. There is nothing to say about the “RAM” at all. There were several alternatives, and they were based on physical principles. They were associated with an electromagnetic relay, acoustic delay lines, cathode ray tubes, etc.
Then the RAM appearance could have been absolutely unpredictable. More often it was magnetic drums or shafts.
With the release of the second generation of computers, it was necessary to think about effective RAM. Just then, magnetic cores with memory appeared. The third generation made a leap forward and began to use microcircuits on which the electronic components of the computer were. Then types of random access memory began to appear. Dynamic was maintained due to the charge of the capacitor, and static - with the help of triggers.
Current state of affairs
Over time, the process has led to the latest RAM. "Operational" is still dependent on the supply of energy. In the event of a loss of power supply, it immediately loses all unsaved data. Nowadays, there are the main types of RAM. There are two of them, as before: static and dynamic. The first works thanks to the trigger, the second to the capacitor.
Both have become more effective. Outwardly, they look like a module with semiconductors, which is organized as a device with free access. Dynamic memory is much cheaper. Further we will deal with each of them in more detail.
Work dynamics
RAM types are different. Among the main ones, dynamic or DRAM can be noted. This is the most common form in computers. Due to the fact that it is more economical. To store the discharge, a special circuit was developed, which consists of two parts: a capacitor and a transistor.
Such a structure is much cheaper and also economical. This is because more capacitors and transistors can fit on one chip than in another version of the module.
The main disadvantage of this "RAM" is its speed. It works slowly, since it takes extra time to change the status of the capacitor: discharging and charging. This process takes ten times more than in the static version. Also, this form has another drawback in which the capacitors are discharged over a period. Moreover, this may be due to electric capacity and a greater leakage current.
It is because of the last drawback that this species got its name: the charge decreases in time, which means that dynamics is observed. However, so that all information is not lost, the capacitor can be regenerated over time, thus extending its life. To start recovery, you must enable the read cyclogram. It applies to all lines of the storage matrix. This event is regulated by the processor or memory controller.
Statics
This is a type of RAM from transistors. SRAM does not require recovery, and therefore received this name. The main advantage of this memory is its high speed. This is due to the fact that the mechanism for attaching triggers and logic gates is simple, therefore, to switch the first ones, you do not need much time.
But you have to put up with high cost and waste. The fact is that the transistors that are in the triggers are much more expensive than in the first form of memory. Do not affect their high cost and group manufacturing methods. Also, transistors take up too much space on one chip.
Static RAM is almost never used in modern PCs. Usually it is placed in order to organize ultra-fast RAM, which can harm system performance, and this is critical.
Appearances are deceptive
In order to externally determine the types of computer RAM, you need to understand them very well. The average user can not do it. Unless, if we are talking about modules for PC and laptop.
Nevertheless, now it is possible to classify several types of RAM. Some of them are used now, some have long ceased to appear on the market, but they can still be found in computers of the old generation. Moreover, many of the previous models were much more tenacious new-fangled options.
FPM
This is dynamic random access memory. The principle of its operation is simple: it receives faster data from the page that was used in the last cycle. This technology corresponds to its name Fast Page Mode. Now it is very rare to meet such a “RAM”, since it served back in the mid-90s of the last century. Then her companions were 486 processors and the new Pentium.
Edo
This is another random access memory, the types of which are not widely known. Previously, it worked already in 1995 and was specially prepared for the first Pentium processor. She became an improved version of the previous one. She worked immediately on two actions at the same time: she selected the next block while sending the previous one to the processor.
Sdram
Very smart version of RAM. It is so fast that it can easily interact with the frequency of the processor. The principle is already more complex: the microcircuit has two parts. In the process of active work, in the first of them there is an appeal to the bit, and in the other the preparation of this action. This module became popular in 1996. Then it was actively used in cooperation with Intel. It was quite fruitful, so SDRAM was popular until 2001.
This RAM memory overtook the previous ones with interest. It has become three times faster than FPM, and twice as fast as EDO. It worked with a frequency of 133 MHz.
DDR
This is an improved version of the previous one. It appeared just in 2001. The main change concerned not the clock frequency, but the work itself. Now, in one clock cycle, data was transmitted twice.
DDR2
It is clear that this version was a continuation of the previous one. It appeared in 2003, but the chipsets for it were made only the next year. As well as the previous "relative" of DDR2, it can transmit data two times in one clock cycle. The main difference between the two modules is the changed clock frequency, which was obtained as a result of structural improvements. This version did not live long because it had some flaws. Due to the increased frequency, it noticeably slowed down in the process of working with memory.
DDR3
Another equally well-known RAM is DDR3. The types of these "RAMs" belong to the SDRAM series. She replaced the previous generation. Used for computing devices, as well as for video memory.
This version of the module has become more careful: it saves up to 40% of energy. It was possible to reduce power through the use of a 90-nm technical processor. In this case, a microcircuit and double-gate transistors were made, which are precisely responsible for the leakage of currents.
The trouble was that the module this time turned out to be modified. His key is now in a different place, so it is impossible to install this RAM in place of DDR2. Nevertheless, this was done for a reason. The electricity parameters do not coincide for these modules, therefore, in order to prevent erroneous settings, they changed the location of the key.
DDR4
New evolutionary RAM. Types of SDRAM have come to a logical conclusion. A new module to the masses came out in 2014. He improved the frequency response and reduced the supply voltage. The main difference from the previous generation: twice the number of banks (16 pieces).
The bandwidth is now also much better and theoretically can reach as much as 25 Gb / s. A new technology has been developed that increases the reliability of all processes. This RAM has its own processor - Intel Haswell-E / Haswell-EP.
RAMBUS
This is a separate random access memory, types whose characteristics are quite high. It was developed in 1996. Intel decided to do it. “RAM” turned out to be an order of magnitude better than its “colleagues”. Well-known concerns got a license for it. Later, several motherboards were created for it. She showed excellent results on them.
It so happened that before its release, Intel discovered an error, due to which it lost about $ 100 million. Now this module is rarely used. But he is still in the PlayStation 2 and PlayStation 3.
Laptops
The difference between RAM for laptops and PCs is noticeable only in size and name. Therefore, repeating all of the above does not make sense. To choose a module for this device, you must also examine all existing types of RAM for a laptop, determine its compatibility with the motherboard and deal with the price category.
The first "RAM" for the laptop was released in 2002. It was a SO DIMM SDRAM model. Now it is impossible to find it anywhere. It worked with a frequency of 100 MHz and 133 MHz. SO DIMM DDR appeared a little later - in 2005. It has become an order of magnitude more powerful. Received 266, 333 and 400 MHz frequencies. The location of the key compared to the previous model has changed significantly. SO DIMM DDR2, relative to its “colleague” from the last generation, has also become more powerful: maximum frequencies reached 800 MHz. The key has again shifted, but by 1 mm, compared to DDR, which led to confusion with compatibility.
SO DIMM DDR3 entered the market in 2009. The location of the key was radically different from the previous model, so inexperienced users now could not make a mistake. The maximum frequencies of this module reached 1600 MHz.
Models of laptops changed, modified, and RAM for them also transformed. The next module was Micro DIMM DDR2. Its volume was 1 GB, which was quite a lot for the user.
Now the situation with RAM for the laptop is twofold. The fact is that many models have an integrated system, and it is not possible to replace the "RAM". Therefore, the demand for modules for laptops is now very small. Those who still need to increase the volume of temporary storage spend a lot of time to find a good option.
Now, in order for a computer to cope with surfing the Internet and office programs, 1 GB of RAM will suffice. But gamers should take a closer look at more powerful options. For example, Kingston SO-DIMM DDR3 4Gb PC10660. This RAM for a laptop is worth almost 2 thousand rubles. Its volume, as the name implies, is 4 gigabytes. Type - DDR3, and the clock frequency - 1333 MHz.
Among other companies that produce high-quality modules, there are Samsung, Corsair, Hynix, Transcend. For owners of desktop PCs, there are very powerful options that computer gamers will especially enjoy - Kingston HyperX FURY Red Series. The set of "RAM" includes two modules of 4 GB. Type - DDR3, and the clock frequency - 1866 MHz. The price of such RAM is 3500 rubles.