On Wed, Oct 25, 2006 at 12:38:52PM +0200, Dave Long wrote: > >Why not etch dies with either tiles of octagons and squares or just > >hexagons? > > Traditionally, DRAM-style memory (tricky cells, regular layout) and > CPU-style logic (simple cells, irregular layout) use different
Until recently, all chips only used orthogonal (Manhattan) interconnects. Introducing diagonals was considered as a kind of a revolution. > manufacturing techniques and lines, so it's relatively easy to get them > in the same chip but relatively difficult to get them on the same die. > > It is possible to build entire systems with SRAM, but it's not usually > cheap. The old line about Crays is that after you bought the memory, > they'd throw in some supercomputer CPUs for free. > > But I get plenty of hits for "embedded DRAM", so maybe this is now a > solved problem? I also keep asking the same question for years, and embedded DRAM has indeed been sighted here and there, usually few MBytes of it. Now that we've gotten multicore (hey, it only took >25 years) I expect embedded DRAM gnawing up the caches isn't too far behind (but then, I keep saying this since the transputer, but it still hasn't happened). In an industry that only clocks progress on linear semi-log plots true innovation has become rare -- it's far too risky at the high end. -- Eugen* Leitl <a href="http://leitl.org";>leitl</a> http://leitl.org ______________________________________________________________ ICBM: 48.07100, 11.36820 http://www.ativel.com 8B29F6BE: 099D 78BA 2FD3 B014 B08A 7779 75B0 2443 8B29 F6BE
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