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New Device Puts SSD In a DIMM Slot
Vigile points out a new take on SSD from Viking Modular Solutions. The SATADIMM puts an SSD in the form factor of a memory module. "The unit itself actually uses a SandForce SSD controller and draws its power from the DIMM socket directly but still connects to the computer through a SATA connection — nothing fancy like using the memory bus, etc. Performance is actually identical to other SandForce-based SSDs though the benefits for 1U servers and motherboards with dozens of DIMM slots is interesting to say the least. Likely priced outside the realm for average consumers, the SATADIMM will likely stay put in the enterprise market but represents an indicator that companies are realizing SSDs don't need to be in traditional HDD form factors."
Why? If it's only drawing power from the DIMM slot, what benefit does that serve? Sure, in a 1U rack it *might* save a trivial amount of space. I just dont see a market for it.
I remember back before computers had onboard drive controllers and there was no such thing as a standard drive interface, they sold ISA hard drive cards, it was a drive & controller all in one. I dont see to much advantage running a drive on a ram slot, you can just dedicate a drive(s) to you work, swap or temp files. I typically do that when editing video, 1 drive holds the raw videos, one drive is a temp drive and one is what the final video files are outputted to when they are rendered. Much faster then using 1 drive or even a single raid to read/write large amounts of data at the same time.
Certainly putting things like swap space and database journal files on SSD would speed things up wonderfully, but how about an OS hack where an SSD drive is a sort of L3 cache between core and traditional disk for dirty disk buffers? Also, I'm wondering about the power requirements between SSD and DIMM RAM.
No folly is more costly than the folly of intolerant idealism. - Winston Churchill
Additionally, if they can squeeze a 256GB into a DIMM form factor, why the are even 4GB sticks of RAM still expensive
Because using flash memory as system RAM would be rather disappointingly slow.
I am not a crackpot.
The price of flash has nothing to do with the price of RAM. They are completely different constructions, and for different tasks. Flash is faster than magnetic storage but still dog slow compared to RAM. For flash you talk access time in 2-3 digits of microseconds. For RAM you talk access time in single digit nanoseconds. For flash transfer rates are in the 100s of MB/sec with anything over 200 being rather exceptional. For ram transfer rates are in the 10+GB/sec.
Same sort of transition again when talking DRAM (what you put in your system) to SRAM (what processor cache is made out of). Again the price goes up massively so instead of 8GB, you are talking maybe 12MB. However again the speed goes way up and access time way down.
While the write speed would be painful compared to real DRAM, the read speed would be comparable.
For large static arrays, and for custom data applications, it could have uses in the form the GP suggests, though it WOULD be a nasty throwback to the days of user ROMs...
However, I could definitely see the potential in having such a thing mapped directly to system memory, then loading a special block device driver to allocate all that "memory", so that memory IO could be used for data storage. It would eliminate the SATA controller's IO bottleneck, but would impose a slight CPU penalty. For systems with multiple CPUs, that wouldnt be much of a problem. You would need to allocate that memory fast though, to prevent the OS from trying to use it like RAM.
Actually I find this potentially quite cool. Not as much for the power source, but the size. Since most mATX boards don't come with mini PCIe slots, if you want to use an SSD drive you need a 2.5" drive or a PCIe card with a mini-slot on it. Both are much larger than a DIMM option.
And with 50gb, this would be very useful in a media box streaming from a server. Now only if the price could come down.
This device seems backwards with today's trends. With virtualizaion gaining ground fast, the ideal setup is to have as much RAM as possible with a SAN back end for storage - iSCSI, FC, whatever. Most local disks on servers today are RAID1 mirrors for the small hypervisor.
So, yes, this device wastes a valuable DIMM slot to give you a less-valuable SATA drive?
I can't think of any scenario where this would be useful unless you're talking about handheld devices - a MacBook Air or tablet of some sort.
Most folk'll never lose a toe, and then again some folk'll...
I've had such things in the embedded world for over a decade.
What's next? NEW! small cards serve as memory devices!
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