I've successfully used ramfs to do this, though with much smaller files.
ramfs ships with stock TS kernels (I'm using TS-11).
Basicaly, you make a mount point:
mkdir /var/ramfs/
then add something like this to /etc/fstab
none /var/ramfs ramfs defaults 0 0
Now, any files you create in /var/ramfs will be forced to be kept in
main RAM without ever going to disk or flash.
The caveat is that this is resident in RAM, and can never be swapped
out or de-allocated, so you need enough physical RAM for everything
you store there as well as everything else you're running. Its nice
and fast though.
-Ilya
On Nov 13, 2007, at 12:19 PM, Art wrote:
> Hello all,
>
> I have been working for sometime now on a web based control system.
> This has both a configuration and operational interface from the web.
> As well as the same controls in hardware. I have been currently
> using a sqlite database for storage of the main data. This doesn't
> seem to be a problem when reading but when I write to the data base
> this could take some time. I really need this to be real time as in
> fractions of a second. I have been looking at shared memory(shm.h) to
> share resources between applications. My problem is the shared memory
> is not big enuf for 4mg to 10 mg worth of data. there is not much I
> can do to shrink that size. I really need to share a data structure
> between applications or process that resides in memory. I would hope
> there would be a way for me to create that data structure in own
> program and pass a pointer to another program to access it. I know i
> would normally get a segmentation error if I try to access memory in
> another programs space. I may need to other IPC methods but I really
> want to allow the programs to function independent from each other. I
> don't really care about race conditions because the data is all last
> action. I just care what the last change was.
>
>
>
>
> Yahoo! Groups Links
>
>
>
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