Explaining RAM

welcome to another video

explaining

computer communications, this time I'm going to talk about random access memory or RAM specifically. I'm going to spend a few minutes talking about the nature and history of RAM before detailing the Ram technologies and form factors used in modern desktop and laptop computers. Computer storage can be volatile or non-volatile. Non-volatile storage includes hard drives and SSDs, as they maintain their contents when the power is removed. In contrast, modern RAM is volatile storage that loses its data when the power is turned off. However, it is the fastest type of storage available and is used to store programs and data when a computer is running.

Kappa 30 RAM is measured in gigabytes, with a gigabyte being just over a billion bytes today. 4 gigabytes is the minimum recommended RAM across a modern Windows PC. With 8 gigabytes or more required for most video editing and other high-end applications, the first type of RAM to come into widespread use was magnetic core storage which featured small ferrite rings that screwed onto a network of cables that avoided voltages through the cables. The cause could be magnetized with clockwise or counterclockwise polarity, allowing for the storage of one bit of data. You can see a magnetic core storage unit here, but I photographed it at the National Computing Museum.

The unit has multiple cause planes stacked on top of each other. above the other with the upper central plane visible through the window in the upper core. Core storage was the most common form of RAM from the mid-1950s to the mid-1970s and was used in the Apollo spacecraft that took humans to the moon in the early 1950s. 1970, the so-called storage began to be replaced by an integrated circuit or Ram ICU. Early personal computers were later equipped with many dual in-line or dip-in RAM chips, as we can see here, such chips usually plugged directly into the computer's motherboard socket, performing RAM repairs and upgrades.

Quite time-consuming and even more significantly chip creep could occur as individual RAM chips have a tendency to pop out of their sockets due to constant thermal expansion and contraction to overcome these limitations. The Ram ship began to be soldered into packages into modules that were in turn plugged in. In a computer, both onboard and standard initially emerged known as Sips and Sims, as you can see, a Sip or single inline package had 30 pins that connected to a row of small round sockets, while the large ones, in theory , Sips could be difficult to install, they were expensive. produced and it was easy to bend or damage their pins, for this reason individual Sims or inline memory modules became the dominant Ram technology, like SIPS, these were initially available with a 30-pin form factor, although later The Sims had 72 pins and unfortunately I didn't.

I have one of those available to show you here, as you can see, however the sims have a sturdy edge connector and clip and lock securely into a motherboard RAM socket. Today's computers are equipped with descendants of sims known as dims or dual in-line memory modules, the key difference between a similar Tim is that the connections on either side of a sim or duplicated where it was in a dimmer are distinct and duplicate the number of connection points in the same available space for optimal performance. Identical pairs of attenuators must be installed in two matching slots or banks on a computer's motherboard, this allows the RAM to run in so-called dual-channel mode which maximizes the speed at which it can be accessed.

Motherboard that can accommodate more than two dimmers almost always have their RAM slots color-coded to indicate the appropriate insertion pairs. As we will see later in the video over the years dimmers have evolved to accommodate speed improvements, it should also be noted that while all the dimmers shown here offer use on a desktop PC, smaller attenuators or small-outline dual in-line memory modules are used. For completeness I should also point out laptops and other small computers but in the late 1990s and early 2000s there was also another form of RAM called rim or Rambus inline memory module, these were similar to those are dimmed, but they are no longer in use.

The ramp can be confusing. Because the specification of a modern dimmer is quite extensive and can be expressed in many different ways, for example the specification for the RAM module we have here could be listed like this clearly, the 4 GB on the front means we have a 4 GB component. gigabytes and as I have already explained that the dark part at the end means that this is a dual inline memory module suitable for use in a desktop PC. We can also see the RAM bit there quite happily, but with the letters s and D in front of it and to explain.

What this and the other terms mean here we need to delve a little deeper into RAM technologies. The memory cells that store each bit of information on a Ram chip can be static or dynamic. In static RAM or SRAM, each memory cell consists of four or more. transistors that hold data while power is applied, in contrast to dynamic RAM or DRAM, each memory cell is built from a single transistor and a capacitor which requires a periodic power refresh because SRAM does not have to be constantly refreshed, it is faster however SRAM is more expensive to manufacture than DRAM because more components are required to form each memory cell because of this, SRAM is used to provide microprocessors and hard drives with very fast internal storage called cache;

However, most other computer RAMs use DRAM technology to provide the highest capacity of the lowest cost, specifically today, personal computers are equipped with SDRAM memory modules. SDRAM is a development of DRAM which stands for Synchronous Dynamic RAM. What this means is that SDRAM operates in sync with a computer's clock cycle, reducing wait times for the processor. and therefore improves performance in the year 2000, a development of SDRAM called DDR SDRAM was introduced. DDR stands for twice the data rate and means that RAM runs twice as fast as two data transfers per clock cycle, while only one since ddr sdram was introduced.

It has been improved several times with later generations called ddr2 ddr3 and ddr4 at the time of making this video in December 2018 a new standard for ddr 5 with ddr5 SDRAM is expected to probably enter the market in 2019 or 2020 the later generations of DDR SDRAM They offer increasingly higher performance and have different physical form factors, specifically at the top here we have a first generation full size DDR SDRAM with 184 pins and below a ddr2 module with 240 pins, then there was a ddr3 SDRAM which also has 240 pins but it has a notch. in a different location to prevent it from being inserted into a ddr2 socket, we finally have a ddr4 SDRAM with 288 pins and again a different notch configuration.

Please note that the DDR3 and DDR4 modules here are supplied with an aluminum heatsink to help cool their chips, but this is not always the case with Ram modules in each DDR generation which are available in a range of speeds. . Here, for example, we're looking at a table showing common speeds for different DDR3 SDRAM modules, as you can see. RAM speed can be expressed in several different ways with a data rate quoted in megatransfers per second and an associated maximum transfer speed listed in megabytes per second, as we can see the megatransfers per second figure can also be combined with a DDR type module, while a pig transfer speed is often included. inside a babel module that has the PC prefix and the DDR generation note, but it is not uncommon for the data rate of an SD ROM to be quoted in megahertz, although megatransfers per second is more technically correct, each generation of DDR SDRAM It was developed to offer greater performance. than the previous one and to illustrate this here is a table of common ddr4 modules that are clearly faster than the ddr3 modules we just saw when in said data note the maximum transfer speed figure in megabytes per second is always eight times higher Data transfer rate expressed in megatransfers per second Please also note that there are no definitive terms in use for the headings shown in these tables with variations in wording used by different manufacturers and standards bodies.

Now I am very aware, but I presented rather a lot of information and could go on to detail even more RAM terminology. However, I think we've now had enough to understand the specification of a standard RAM module, so if we go back to the component we had previously, hopefully it will now be clearer, but its specification. refers to a 4 gigabyte module based on fourth generation double data rate synchronous dynamic RAM, we can also see when the module operates with a data transfer rate of 2,400 megatransfers per second equivalent to a hog transfer rate of 19200 megabytes per second and finally we also know that this Ram before us is a dual inline memory module form factor, so what do you need to know when selecting well the RAM to build or upgrade a PC without delving into even more technicalities?

The key things to keep in mind though are, firstly, desktop PCs require dimming. and laptops require sodium, secondly you need to install the correct DDR generation for your motherboard as there is no backward or forward compatibility so for example you need to put ddr3 RAM on a ddr3 motherboard, ddr4 ram on a ddr4 motherboard and so on, thirdly, you need to install Ram with a speed, but it is compatible with your motherboard. All motherboards accept several different module speeds, so make sure the RAM you get is suitable for your board. Finally, when the option is available, achieve dual-channel performance by installing identical pairs of color-coded RAM modules. from your RAM slots and the instructions in your motherboard manual in the early 1980s the first computer I owned and programmed was a Sinclair zx81 and it has a kilobyte of RAM and since modern computers have gigabytes of RAM , this means that modern computers have over a million times more RAM than the first machine I used in the program and that seems absolutely extraordinary to me and makes me speculate on the fact that most likely many of you who are watching this video right now they end up having computers. which have terabytes and even petabytes of RAM and we can only imagine what that amount of RAM will actually be used for in the future, but that's all for another video, if you enjoy what you see there, hit the like button if you have.

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