RAM-DISK or SMART-CACHE for SPARCII running UNIX

[Thomas S Magg]

I'm looking for the PC/DOS/WINDOWS RAM-DISK equivalent for a SUN SPARCII
running UNIX.  Does anyone know if such an item exists?

Specifically we have an application written in C++ that accesses a 20MB
file extensively.  Using benchmarks we determined that the I/O from the
20MB file was causing a performance bottleneck ie. to draw a configuration
map took: 1 second to set-up, 32 seconds to read the configuration from
the 20MB file, and 5 seconds to draw it.  Internal RAM is no problem - we
have 32MB and can easily expand to 96MB.  We could rewrite the C++
application to take the file and put it into RAM and then access it from
RAM, except that several dozen procedures access this file so it wouldn't
be a trivial effort.

What could be a trivial effort though is using a RAM-DISK.  I'm familiar
with RAM-DISK which I have on my PC.  If I could do the same on UNIX we
could simply create a 20MB ram filesystem and copy the the file there.
The only change to the application would be to change the file path.  

The second less optimal (than the RAM-DISK) would be to set up a
SMART-CACHE (again I have one on my PC) for the file system that has the
20MB file - I would think that UNIX does some internal caching itself, but
I'm not sure how big a cache area it uses.  If it does do internal
caching, is there a way to adjust the caching size to above 20MB?  The
only reason I think this would be less optimal than a RAM-DISK is because
we have a bunch of other stuff running on which the performance isn't
critical which might "clog" up the cache.

Thanks in advance for any replies.  If anyone is interested I can
summarize responses and send via e-mail - let me know.

Thanks,

Tom Magg, attbl!hou2d!tsm, (908)-615-4627, AT&T HR 2H-096, Middletown, NJ 07748