Non-Volatile DIMMs To Ship This Year
Lucas123 writes "Both Viking and Micron plan to ship cards that combine DRAM and NAND flash on a standard DDR3 DIMM. The cards will have twice as much NAND flash as volatile memory. For example, the non-volatile DIMMs will come in capacities ranging from 4GB of DRAM to 16GB and 8GB of flash to 32GB of flash. Micron also sees its NVDIMM card being used as a storage tier, as cache for RAID systems, system check pointing, full system persistence, data logging, de-duplication and fast access to metadata. Without providing specifics, Viking said the NVDIMM cards will cost roughly a few hundred dollars each, more than a standard DDR3 DIMM module but still inexpensive enough for server and storage admins to consider for boosting application performance."
What's the main advantage of this over running a server using RAM as disk cache? I'd like to think that no one would use a server for real work without it being on a UPS, so what's the advantage over having a controlled shutdown when power is lost vs having non-volatile data in your ram stick?
Why does comment posting not work this thread..?
And now with these chips the government will have an even greater reason for shredding their computers.
Proffits increase because you'll pay more and more often for a defective design. REMEMBER IGNORANCE IS STRENGTH.
AMD A10 gets a substantial to it's graphics, making a decent single chip CPU/GPU combo.
Ram gets flash.
Intel do a NUC, tiny PC.
Now if only they can get the size of the desktop PC into a decent tiny form factor, keeping a decent amount of processing power, lose some of the fan, and keep the terabyte plus of disk space, the PC can get refresh.
It is bad enough that flash is worming its way into hard drives, but memory? True non-volatile memory like MRAM would be interesting, but I don't want unreliable and short-lived garbage like flash soldered together with other components. All this does is ensure that devices will be destined for the landfill that much earlier, but of course that is a "feature". There ought to be laws enacted to prohibit non-replaceable consumables, wether batteries, flash memory, or whatever else.
While on the subject of memory features, ECC should be first on the list.
but could you run linux in it?
Will this increase problems with malware? Just wondering.
Now Windows problems will not even be fixed with a reboot anymore. Reinstalling will be the only way out.
Since a disk controller can reorder or defer writes to improve performance, you can't be guaranteed that writes are finished until you call fsync. (There are other modes, but fsync is a straightforward way to explain this.)
Normally, writes to disk can't be confirmed faster than one per full revolution of the platters. Thus, a 7200 RPM disk can not perform more than 7200 transactions a minute. This is a huge bottleneck for any kind of persistence mechanism.
Using flash as your caching mechanism allows you to get both reliable commits and allow the disk controller to be far more highly optimized.
First, if the system presents the DIMM as a contiguous chunk of 'RAM', then this move would be about higher apparent memory capacity at lower cost, and the non-volatile aspect is just a side-effect.
I am also aware of firmware/system design in the enterprise space that would distinctly recognize the non-volatile portion of similarly designed DIMMs and not put it in the memory map, but instead describe it in a block storage sort of way complete with UEFI drivers to make it a boot volume. Basically, SSDs without having to go out to the chipset at all and without having to worry about the current throughput limitations of SAS or SATA.
XML is like violence. If it doesn't solve the problem, use more.
the article isn't loading for me, so it's possible that this is discussed there ...
but what i'd really like is a block of nand that's accessed directly. SSDs present a block interface and translate the writes to the nand. presumably these dimms continue to present the RAM model to the computer and do some behind the scenes translation
nand has a performance characteristic that is quite different from both RAM and block devices, and shoehorning it to look like one or the other is limiting it's usefulness. eg, SSDs only let you do a single write to a block before erasing it, but you can actually continue to update a block - it's just that the bits are additive. for some algorithms this would be useful and would dramatically extend the write endurance. but since the SSD interface doesn't expose that capability we're left brute-forcing the nand
tl;dr: i want raw nand
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The idea of using this kind of memory with servers is certainly a slippery slope. When a server is running constantly, fans and hdds keep moving. If they stop, there is no guarantee if they'll start back up again.
I don't think exercising the server's (automatic) on/off function on a daily basis is a bright idea. Might be green, but not bright.
I was thinking of this very scenario not too long ago. Many ARM (and other archs) embedded microcontrollers support external memory busses which can have a mix of SRAM, SDRAM and Flash. The flash can hold a binary image and/or a flash file system. I imagine the combo DIMMs would provide you with a similar setup, allowing a flash file system along with standard DDR RAM on the same memory controller.
I must admit that I can't wait to see performance numbers for read speeds. Using it as a frequently written cache is a stupid idea as you will wind up wearing down the flash BUT if its used to cache frequently read files then you really have something. What would be interesting is if you could use execute in place to run software directly from the flash. There could be a mechanism where the flash disk is mapped into the file system. The OS or the user can decide which files can be loaded from disk to flash cache and a link or pointer now points to the flash instead of the disk making it transparent. Loading a program could be done in a few seconds. The OS could even map system files to the flash so booting could take seconds and energy saving suspends or shutdowns can resume in a second or so.
I imagine it would be a great boost for gaming, probably the biggest (and most likely target) market for these DIMMs. Games would benefit greatly from the break neck load speeds brought about by having the game already in memory. Gigabytes of game files can be loaded into flash and you can jump right into the game. Game save states could be loaded into flash and instantly recalled. Half life brought us the continuous game experience where there are brief load points between sections instead of load screens. Now that can be turned into continuous game play as all game data is already in a portion of main memory.
I think they might not benefit much else, maybe video editing but I think you would need over 100GB of flash storage for it to be useful. Using flash might not be the best idea but its the cheapest highest capacity non volatile memory we have at the moment. CellularRAM (PSRAM) and MRAM are other contenders but capacity and availability are an issue. MRAM is still in development and PSRAM is available but currently its suck at 16MB capacities.
And lastly, people assuming your encryption keys could be pilfered, the flash will not be used as RAM. It can't because Flash can't be written to on a per address basis like RAM (BUT MRAM and PSRAM can). But if you suspend by writing memory contents verbatim to flash, then you have a problem. My guess would be it might be possible to partition the memory so sensitive RAM contents would be discarded. Its up to the OS makers to implement these mechanisms. I imagine Linux and the BSD's would be most concerned about these potential security pitfalls and ensure this does not happen. I would like to think both Microsoft and Apple would be smart enough to also avoid such a glaring security hole. Maybe we can have a memtest like utility either in ROM or disk that zeros out the FLASH as a boot option.
From what I gather, it sounds like a Ready Boost card... Progress!!!
your RAM!
My God can beat up your God. Just kidding...don't take offense. I know there's no God.
Does Windows 7 and Windows 8 have instant on capability yet or is that slated for Windows 9? I think Linux has instant on capability already (not sure about MAC's) so if I am right for a lot of people it's still premature to get the value out of the expense but I don't know for sure. http://rawcell.com.