Common terminology for server memory

Operation Steps:

What is server memory? What is the difference between it and the memory on a regular PC?

Answer: Server memory is also memory, it and we usually see in the computer city in the ordinary PC there is no obvious difference in appearance and structure, it is mainly in the memory of the introduction of some new technology, ordinary PC memory on the server is generally not available on the server to recognize, This means that the server memory can not be arbitrarily for cheap with ordinary PC memory to replace the reason.

Some people have some kind of technology of memory is called "Server memory", in fact, is not comprehensive, the server of these memory technology is currently in the view of the server is dedicated, but can never be guaranteed only server-specific. These new technologies are first used on the server because the server price is more expensive, conditional to apply, these new technologies due to the price of the reasons for the temporary PC machine can not be applied, but with the fall in the price of accessories gradually to the general PC machine, Just like the original parity correction memory was first applied to the server, now is not very common? So server memory is not a specific, it is the application of new memory technology in different time periods.

　What is buffer and unbuffer?

A: Buffer is the buffer, can also be understood as a cache, the server and graphics workstation memory more applications, capacity of more than 64K, but with the constant increase in memory capacity, its capacity is also increasing, with buffer memory will be the memory read and write speed of a greater increase, As early as 168 cores EDOECC server memory is mostly buffer,unbuffer to indicate that it does not have a cache. With buffer memory almost all with ECC function, Unbuffer memory only a few with ECC function. It also has a more pronounced feature on the memory number, in the case of Virgin Memory PC133 128M, which is numbered Me16641u4ss-cl3, where the letter U represents Unbuffer.

　　What is register?

A: Register is the Register or directory register, the role of memory in our right to understand the catalog of the book, with it, when the memory is read and write instructions, it will first retrieve this directory, and then read and write operations, which will greatly improve server memory efficiency. The memory with register must be buffer, and the register memory that can be seen now has ECC function, its main application in high-end server and graphics workstation, such as IBM Netfinity 5000.

　　What is ECC memory?

A: At the moment it's about server memory, there is a unanimous emphasis on the need to buy ECC memory, the speed of ECC memory, in fact, is a misconception that ECC memory success is not because it is fast (speed is not related to the memory type only), but because it has special error correcting ability, Keep the server stable. ECC itself is not a memory model, nor is it a special memory technology, it is a kind of computer instruction widely used in various fields, it is a kind of instruction error correcting technology. Its English full name is "error Checking and Correcting", the corresponding Chinese name is called "Bug Check and correction", from this name we can see that its main function is "Discover and correct error", It is more advanced than parity correction technology mainly because it can not only detect errors, but also to correct these errors, these errors after the computer can correctly perform the following tasks, to ensure the normal operation of the server. It's not a memory model, it's because it's not a technology that affects memory structure and storage speed, it can be applied to different types of memory, as we mentioned in the previous "parity correction" memory, it is not a memory, the first application of this technology is Edo memory, now the SD also has applications, and ECC memory is mainly from the SD memory began to be widely used, and the new DDR, RDRAM also has a corresponding application, the current mainstream ECC memory is actually a kind of SD memory.

What is LRDIMM memory? (load-reduced DIMMs, low load DIMMs)

LRDIMM reduces server memory bus load and power consumption by using new technologies and lower operating voltages, and allows the server memory bus to achieve higher operating frequencies and significantly increase memory support capacity.

In contrast to the usual unbuffered DIMMs, the registered DIMM used by the server improves the memory support capacity by buffering the signal on the memory strip and driving the memory particles, while LRDIMM memory changes the register chip on the current RDIMM memory to a IMB (Isolation Memory buffer) memory isolation buffer chip to reduce the load on the memory bus, and correspondingly further increase the memory support capacity. Compared to the usual Rdimm,dual-rank Lrdimm memory power consumption only its 50%,quad-rank Lrdimm can also be low to 75%.

Currently, a typical NEHALEM-EP processor can support 3 memory channels, with a maximum of 3 Rdimm per memory channel, and with Lrdimm memory, the same system can support up to 9 DIMMs per channel and memory capacity up to three times times the original.