5 minutes to change people storage rookie crash course

A comment from a friend commented today and asked me, how can I tell the female friends about memory and storage? Xiao Bian now puts this part in order to see if he can help him and those who have similar needs. However, Xiao Bian also wanted to ask, would she teach her female friends to learn advanced science and technology knowledge and scatter dog food? Especially female basin friends who are interested in science and technology knowledge, where can I sell?

Don't make a mistake with RAM+ROM

First of all, from the basics, RAM is memory, ROM is storage space, and the two should not be confused. The mobile phone is also a good computer, it is almost identical structure, memory + storage. The former is the use of exchange calculation data, and the latter is the use of stored data.

Having said the effect, said technology, memory, whether it is DDR3/L, DDR4, LPDDR, or even video card memory GDDR, collectively referred to as "volatile storage", to put it simply, that is, power can not save things. But its advantage is that the speed is so fast that it is far from being comparable to any type of storage.

Storage, whether it is a solid-state hard disk or a mobile phone memory chip, is collectively referred to as “non-volatile storage” and is easier to understand than “volatile storage” of memory. After a power failure, they can also save content, which can be achieved Stored features.

Of course, there is no absolute definite thing. Intel now launches Ao Teng to break the boundary between the two - the speed and storage of memory can preserve the features of content, but the price is relatively inexpensive, and it is not known whether this Dongdong can change the present. RAM+ROM architecture.

What exactly is memory?

DDR3/L, DDR4, LPDDR, and GDDR are random memories (memory). Their role is to exchange data. Whether it is a computer or a mobile phone, when processing a large amount of computational data, a container is needed to temporarily store the calculated/calculated data. The content is then handed over to other parts of the conversion calculation.

The DDR3/L on the computer, the former is a standard voltage product, the latter DDR3L is a low-voltage product; DDR4 is only one, the reason is very simple, from the design to take into account the requirements of low voltage, so unlike the DDR3 era Also distinguish.

LPDDR is mainly LPDDR3 and 4, which are simply DDR3/4 memory on mobile platforms. The difference is that the meaning of LP represents low-power double data rate memory, which can bring equivalent performance (speed) while , taking into account less energy consumption.

Another thing to say is GDDR. They are also derived from memory. That G means Graphics, which means that graphics use DDR memory.

How is flash memory so messy?

In fact, the flash memory is not messy. Simply put, the current flash memory types such as SSDs and mobile phones can be collectively referred to as NAND Flash. NAND Flash has a faster erase time, and each memory cell has a smaller area. This allows NAND Flash to have higher storage density and lower cost per bit than NOR Flash. At the same time, its erasable count is also ten times higher than NOR Flash.

NAND Flash is currently divided into MLC particles and TLC particles, meaning two different technologies to achieve the flash memory chip, the latter wins at a lower price, but the number of rewrites is less, the former more erased but the production cost is slightly higher . Both EMMC and UFS may use TLC or MLC particles. To be exact, NAND Flash is an integral part of UFS or EMMC.

EMMC

EMMC's full name is "embedded Multi Media Card," which is an embedded multimedia memory card. , eMMC is based on NAND Flash chip, an additional integrated main controller, and the two "package" package into a BGA chip. The speed of EMMC depends on the bus interface. Currently, EMMC's bus interfaces are mainly eMMC 4.4, eMMC4.5, eMMC 5.0, and eMMC 5.1. Their "theoretical bandwidth" is 104MB/s, 200MB/s, 400MB/s, and 600MB/s, respectively.

UFS

UFS's full name is Universal Flash Storage, which is universal flash storage. UFS was actually launched to replace EMMC. The theoretical bandwidth of UFS 2.0 HS-G2 is 5.8 Gbps, which is approximately 740 MB/s, and the theoretical bandwidth of the faster UFS 2.0 HS-G3 is 11.6 Gbps, which is approximately 1.5 GB/s. However, this is only a theoretical speed. To achieve such rapid speed, we must also look at the development of flash memory technology. In addition, UFS 2.0 no longer uses the half-duplex mode of eMMC after switching to the serial bus. Instead, UFS 2.0 uses the full-duplex mode, allowing data to be transmitted and received simultaneously.

The specific Xiaobian once pushed an "What? Huawei's flagship P10 encounters a "flash memory door!" ” Explain the difference between UFS and EMMC, no more to say here.

Summarizing, memory is a unified term, including a variety of memory technologies, such as DDR3/L, DDR4, LPDDR, etc.; flash memory is also the case, through the combination of particles and master control, with different technical standards evolved Several different types of storage devices, such as EMMC, UFS, and the like. At the same time, flash memory particles themselves have different technical ways to achieve. Do you understand this now?