On 10/18/2012 4:09 PM, V G wrote:
> iple slots that can address more than 256GB of RAM would be nice.
>
> How expensive and difficult would this be? Most of the logic is already
> there, the only thing really is the electrical engineering (routing,
> layout, etc.) considerations and the memory addressing logic which doesn'=
t
> seem too hard from what I know (I've built a simple memory controller on =
a
> Spartan 3E for my PIC32 in the past).
It really wouldn't be practical unless you just want to do it for a=20
learning experience. What you are basically
creating is a ram disk and there isn't a whole lot of applications that=20
are going to make use of it versus just using
a SSD. Some of the newer SSD are very fast, approaching the 1 gigabyte=20
/sec  speeds and capacity is getting larger and cheaper every day.

Something like this would have been more practical 5 years ago but now=20
with SSD it really isn't worth the cost. I can get nearly the same=20
performance as the design you are talking about with a $200 drive and=20
have 2x or 3x the capacity.


If you really wanted to do it there is no need to go the FPGA route as=20
there are already PCI-E chipsets that can interface with the ram and a=20
current motherboard slot complete with all the necessary functions .  it=20
appears to the OS like any other device on the bus and with drives can=20
be anything from a ram disk to extra ram for an application.
Mark

--=20
http://www.piclist.com PIC/SX FAQ & list archive
View/change your membership options at
http://mailman.mit.edu/mailman/listinfo/piclist
.