Steve Dekorte wrote on Thu, 17 Jun 2010 12:42:11 -0700 > Does anyone know of any projects that have used associative memories (which > are now large and relatively cheap) for implementing dynamic runtimes? Could > such an approach give us single cycle dynamic lookups and (for the most part) > eliminate the need for complicated compilers?
I investigated this issue in 1990 when I had a scholarship to design an object oriented processor as I was graduating in chip design. Associative memories were particularly fascinating to me since they aren't practical to implement with discrete components or even FPGAs. After becoming available as standard components in the early 1980s, they seemed to have disappeared by the time of this project. Even in custom chips they don't seem to be used much - at least caches moved from fully associative in early designs to two or four way associative today. MMUs (the TLB, translation lookaside buffer, part) and network packet matching seem to be their most popular current use. Given that you are asking on this list, I imagine you have read Ian Piumarta's "Quantum Object Dynamics" paper? http://www.vpri.org/pdf/m2009002_qod.pdf That is the kind of issues I was looking into back then, with a lot of inspiration from Self. These days I see these ideas used in practice in Io, Lua and Javascript (and probably others that I am not aware of). The wonderful results that the Self group achieved with compilation techniques on conventional architectures made me interrupt this line of research. Even a one clock message send is no match for message sends that are entirely compiled away! A few years later I came up with the idea of turning the associative memory on its head - instead of having the fastest possible match for a single result, why not have many simultaneous searches even if each one is the slowest possible algorithm (a linear search)? Like traditional CAMs (content associative memories), this hardware is also impractical to simulate on FPGAs or discrete parts. I plan to work on this after my current SiliconSqueak project, and have a very brief description of it at http://www.merlintec.com:8080/hardware/19 -- Jecel P.S.: I don't know if this will make it to the list - my last few posts bounced _______________________________________________ fonc mailing list [email protected] http://vpri.org/mailman/listinfo/fonc
