Prev: gethostbyname doesn't accept IPv6 addresses
Next: 7 x = ."It's" IF ." " ELSE ."not " THEN ."equal"
From: Robert on 8 Mar 2010 04:05
"Thomas Womack" <twomack(a)chiark.greenend.org.uk> wrote in message
news:VJk*tSq5s(a)news.chiark.greenend.org.uk...
> In article <jwvmxyjlwyp.fsf-monnier+comp.arch(a)gnu.org>,
> Stefan Monnier <monnier(a)iro.umontreal.ca> wrote:
>>> I'm well aware of RAM drives that use main memory, I'm talking about
>>> building something that is far faster than a Flash disk, but
>>> (hopefully) at a lower price point than main memory RAM.
>>
>>Is that at all possible? IIUC current DRAM is mainly driven by "dollars
>>per megabyte" already (i.e. speed is a very secondary concern), so
>>I wonder if there's really much we can do to reduce its price.
>
> You can't get much cheaper than current DIMM sticks, but you can
> probably get bulk memory substantially more cheaply than having it be
> the main memory of whole computers: attach it to controllers which are
> not whole quad-core CPUs. Be prepared to have two dozen controllers
> each with half a dozen DIMMs attached, and outwardly connected to some
> protocol designed to be the cheapest transcievers available at
> 1GB/sec; have a master communicate with whatever controller is
> connected to the memory it wants.
>
> Though demand for this probably won't be enough to make the custom
> controllers and motherboards substantially cheaper than $100 Athlon64
> chips on $100 motherboards talking to 8G of DDR2 bought for $200, and
> a $125 hypertransport HCA switching through a $750 8-port
> hypertransport switch.

A bit overkill. I would like a cheap 32 bit CPU, maybe an Atom. Load it
with 4
gigs of RAM. Do some SOC style stuff and build 3 SATA ports on it - 2 for
storage,
with a SSD and a big rotating disk. The other port would be a
SATA end point allowing you to receive SATA commands and answer IO requests.
Put a bit of flash on it for a customizable linux distro with some common
compression utils, like bzip, gzip, LZO, LZA, etc. Make it all fit (drives,
cpu, etc) into
a 5.25" drive bay.

This would allow database style things to be offloaded with results
available via
DMA. Data would be pre aligned, swizzled, etc.

From: Noob on 8 Mar 2010 08:25
Tim McCaffrey wrote:

> If you are going to use it for a paging device, it makes more sense to
> use some cheap DRAM technology than try to use a Flash based device.

How cheap is cheap DRAM?

AFAICT, MLC NAND flash is currently cheaper than any DRAM technology.
Am I mistaken?

The lowest price for DRAM I could find is 13-15 EUR per GB.

vs 2-4 EUR per GB for MLC NAND flash.

Regards.
From: Scott Lurndal on 8 Mar 2010 13:15
Thomas Womack <twomack(a)chiark.greenend.org.uk> writes:
>In article <jwvmxyjlwyp.fsf-monnier+comp.arch(a)gnu.org>,
>Stefan Monnier <monnier(a)iro.umontreal.ca> wrote:
>>> I'm well aware of RAM drives that use main memory, I'm talking about
>>> building something that is far faster than a Flash disk, but
>>> (hopefully) at a lower price point than main memory RAM.
>>
>>Is that at all possible? IIUC current DRAM is mainly driven by "dollars
>>per megabyte" already (i.e. speed is a very secondary concern), so
>>I wonder if there's really much we can do to reduce its price.
>
>You can't get much cheaper than current DIMM sticks, but you can
>probably get bulk memory substantially more cheaply than having it be
>the main memory of whole computers: attach it to controllers which are
>not whole quad-core CPUs. Be prepared to have two dozen controllers
>each with half a dozen DIMMs attached, and outwardly connected to some
>protocol designed to be the cheapest transcievers available at
>1GB/sec; have a master communicate with whatever controller is
>connected to the memory it wants.
>

http://violin-memory.com/Violin_1010

ain't cheap.

s
First  |  Prev  | 
Pages: 1 2 3 4 5 6 7
Prev: gethostbyname doesn't accept IPv6 addresses
Next: 7 x = ."It's" IF ." " ELSE ."not " THEN ."equal"