permanent RAM harddrives

[SereneXpain]

I was researching RAMdiscs the other day and it occurred to me that if the RAM had continuous power flowing into it from a dedicated supply that isnt affiliated with the PC, then you could basically make a harddrive of RAM that can run the OS and all your programs. Then this drive can have continuous backups onto a regular harddrive in case u ever loose power or decide to move ur pc.

My question is: has anyone created this kind of hardware with large amount of RAM stuffed into a small harddrive sized box and connected through pci-E (like a pci-e ssd cards) or maybe some other faster connection? Or maybe just one large ram module with like 500gigs of memory. I know this would be super expensive but this is just all enthusiasm and people/corps have money. So im just wondering was this ever built or even possible to be built aside from the immense amount of money involved in making this?

EDIT

I found this posted in a similar thread

http://archive.news.softpedia.com/news/RAM-Drives-the-New-Trend-in-Storage-73962.shtml

Then that led me to this:
http://www.ddrdrive.com/menu1.html

I still dont understand how it all works yet but will look into it. Thanks for your help guys!

 

[digitaldoc]

http://www.pcworld.com/article/260918/how_to_supercharge_your_pc_with_a_ram_disk.html

What you are describing is a RAMdisk, which was talked about a few years ago.

While you could still do this, with the availability of SSD's at affordable prices these days, I can see why interest has dwindled on RAMdisk.

 

[someguynamedmatt]

In theory it might be possible - I'm a computer (hardware) engineering student, and have done a bit of work with keeping volatile IC's and various types of memory in a 'standby state' to hold information, and so I've actually thought of this idea quite a bit. It wouldn't be that hard to develop - maybe a dual slot PCIe design, with half of the height used to hold a battery backup unit that would sustain the RAM, and the other half used for the PCB itself which would consist of essentially several DDR3/DDR4/Whatever DIMMs with ECC, a relay switching network that would hand off power delivery on shutdown/power-loss to the battery, and enough capacitance to sustain the memory until those relays/FETs can switch. If you're REALLY feeling ambitious, drop a 2.5" drive + internal controller in there and work out a way to essentially run the two subsystems in a RAID-1 mirror. I doubt you could pack all the needed hardware into a 3.5" hard drive enclosure, but I suppose I've seen stranger things happen.

I can only assume the reason this has never been done is because it would be an extremely volatile and cost-inefficient method of storage. The biggest issue is that your information's shelf life would essentially be limited to however long that particular battery could consistently hold a charge. The real money ends up being invested in technology that goes to the enterprise segment, and that tech generally trickles down to the consumers, at least from my experience. These big corporations can pack enough drives in a RAID array to get their mass amounts of throughput without sacrificing reliability, and so there's never been much call for an ultra-extreme storage design like this. It just wouldn't be profitable enough to produce, and so we don't have it yet. I might end up with some funding for a capstone research project to look into designing something like this if things go well... I've actually got a bit of a plan involving a Xilinx Virtex FPGA to handle hot-backup of the DRAM, but that day may never come, so I'll just have to hope and wait. It would not be cheap, I can say that much.

Edit: Not quite a RAMDisk... I'm thinking actual hardware that would function just the same as any other SATA hard drive. Drop it in, install Windows/Linux and you're good to go. Standard interfacing, commands, and everything. It would be interesting.

 

[SereneXpain]

@digitaldoc yes u are correct i edited my post but im still thinking of a more permanent version of RAMdisk purely for enthusiast purposes. I mean ppl use liquid nitrogen to overclock nowadays... Why not have a super fast read/write speed that boots an os in about 1 second.

@someguynamedmatt that answer was perfect and id love to see updates on ur research. Or if you find that someone has done this and created what you talked about in ur post, give me a hollar cause im quite interested.

 

[someguynamedmatt]

Trust me - I've been looking, but with SSDs these days getting faster and faster, people seem to just be losing interest. My thoughts are still basically to interface everything through an FPGA - using something like an M.2 controller, you could pull a theoretical 2GB/s... instead of feeding that to a chunk of NAND memory, I bet it would be possible to interface (it with a bit of modification) to a chunk of memory space across a set of DIMMs. Then, you'd have to take the command set inbound to that M.2 controller and duplicate it; this would then be sent to a second controller which would write at the same time to a backup unit... you'd need enough 'cache' on that backup so that it doesn't get loaded up with data as it tries to write at ~300MB/s or so while the RAM-Drive is trucking along at gigabytes per second. That right there is a big problem if you want absolute reliability... to have fully redundant information, you'd need a lot of backup - suppose your RAM is written to at just 1GB/s (we have SSDs that can pull this already), and the backup is a HDD at 100MB/s; for every second of continuous writing, you're loading the backup queue with nearly 900 megabytes of data. That would pile up fast with a large transfer. This would definitely call for a new purpose-built controller, and some way of dumping that backup load in case of some sort of failure.

http://arstechnica.com/gadgets/2008/05/storage-roundup-ramdrive-fast-inconvenient-ssd-a-mixed-bag/
^There is actually the last attempt I can remember at putting something on the market... it never really caught on.
http://en.wikipedia.org/wiki/HyperOs_HyperDrive#HyperDrive_5
^The HyperDrive failed pretty miserably, if I remember correctly.

 

[digitaldoc]

Interesting.

With the current SSD's, there will not be much reason to develop other storage solutions for the next few years.

Beyond that, we may see optical quantum memory.

http://www.nature.com/nphoton/journal/v3/n12/full/nphoton.2009.231.html