Content reproduced:
Figure know Memory : https: //zhuanlan.zhihu.com/p/108058770
Fast read memory tag : https: //zhuanlan.zhihu.com/p/26255460
The maximum server memory is how much? What constraints some of it? : Https: //zhuanlan.zhihu.com/p/60830925
Why are computers so eat memory : https: //zhuanlan.zhihu.com/p/37449840
Hardware-depth understanding of principles : https: //zhuanlan.zhihu.com/p/26327347
How should the memory plug? Why do you want to remotely plug from? : Https: //zhuanlan.zhihu.com/p/60830925
Figure identify memory
Today we'll take a look through photos of each part of the memory, and the memory of several forms of organization.
We start with the beginning of the following:
A memory positive and negative
A variety of colors which things are what, who can answer them? Let's look at eleven:
Yellow box: 2GB 1Rx8 PC3 10600R 9 What does it mean? The first read the above article ( HTTPS: // zhuanlan.zhihu.com/p/26 255 460) Friends will be able to know the result of the majority. Yes, 2GB is the capacity; 1Rx8 means of a Rank memory, each memory chips provides 8 bit; PC3 refers DDR3; 10600R refers to the bandwidth of 10600MB / s (clock 1333MHz), R means which is RDIMM ; 9 CL delay.
Red box : This is the R RDIMM server, which is the RCD. UDIMM Desktop do not have this.
Green: storing the memory SPD vendor ID and timing.
Blue : Fly-by mode to cope with the connection data signal, ODT resistance to prevent the reflected signal.
White : memory chips. We count the number of front four, five back. How so sparse? Why not an even number, the computer industry is not a power of 2 admirers of it? Is not even because of a particle do use ECC (almost all are supported RDIMM ECC). Because each memory rank of 64bit data to be provided, x8, only provides a particle 8 'bit, so 64/8 = 8 to 8 particles, each of the four sides.
Is not all 1Rx8 are so sparse it? On the contrary, because most of the memory are two of Rank, 1Rank often shrinkage version. To effectively utilize the same board, 1R is often one-sided memory:
This memory is 1Rx8 PC2,4200U, so it is for DDR2 UDIMM. Note that it is also 1Rx8, but its front has only eight memory chips, neither 5 nor 4. Because it does not support ECC, so it can provide all of the side has 64bit, so its opposite is this:
pay attention to the back reserved spot, all labeled, it transformed into a 512MB 2Rx8 of the memory!
We look ordinary 2Rank memory:
Let's look at the label: 2Rx8 of RDIMM. This DIMM is often a positive Rank, opposite a Rank. RDIMM is not the middle of the RCD particles, particles front nine, an ECC, 8 memory particles, just right. If we turn back, we will find nine particles, positive and almost exactly the same.
Do question the
good, we have to be a problem, memory below this cover with a thick heat sink below what it should be?
Of course, look Tags: 4GB 2Rx4 PC3-10600R-9. And it seems almost in front of? Note that the x4, which means that each particle provides only 4 bit, so provide 64bit, requires 64/4 = 16 particles! x4 memory is often limited in the capacity of the individual particles, in order to improve the overall capacity of the memory employed in the method.
And this memory is 2 Rank, or the support of ECC RDIMM, so the memory armored Here are some dense memory chips! All we have to verify:
on each side there are 18 particles, 16 + 2 (ECC have two, because each only offers x4, requires two 8bit data in order to provide the required ECC). You guessed it!
Other types of memory
the rest of us both Memory:
This half-height and full-height memory memory is no essential difference, mainly used in space-constrained chassis.
Double-sided 1R x 8 ordinary notebook memory. As previously described, need particles 8, each of the four faces. Where S represents the SoDIMM 12800S.
2R x 8, a front rank, a negative rank. 8 on each side are required particle.
The support ECC UDIMM, 1Rx8. 9 particles is required, the opposite is empty.
Conclusion
move finally to take a look DDR2, DDR3 and DDR4 three generations living under one roof, pay attention foolproof notch position
