Re granularity:
I did find pricing for Micron x4, x8, and x16 chips, but nothing interesting (prices were the same), and I couldn't find production quantities, which would have been the really interesting thing. But of course I found lots of other interesting items on granularity of memory systems:
Hidemori Inukai, chief manager of memory-product development at NEC, said it's becoming tougher to meet minimum granularity requirements for PCs using traditional power-interface DRAMs, such as SDRAM and EDO DRAMs, because they must accommodate a PC's 64-bit-wide memory path.
To meet the 64-bit bus requirements, a PC needs at least eight 8-bit-wide SDRAMs or four 16-bit-wide SDRAMs on one module, regardless of the density of those chips. If 256-Mbit DRAMs are used to meet those requirements, they produce a minimum granularity of 256 or 128 Mbytes-which exceeds the 64-Mbyte memory requirement assumed for future low-end PCs, observers said.
Another possibility is a 32-bit-wide SDRAM, only two of which would meet the needs of a PC's main-memory subsystem. But NEC's Inukai said that widening a DRAM's I/O increases its power consumption. "In general, we want x16 from an IC drivability point of view," he said.
techweb.com
The problem I have with the above quote from NEC, is that it is pretty obvious that RDRAM is a real power hog. So why is he reticient about going to x32 memory chips? I've got some running on a system I designed, and they are cool, cool, cool to the touch. (Of course I fondle my chips frequently, it's important to feel how the little machines are humming running. Unfortunately, every now and then I end up with someone's darn logo burned into my finger.)
A couple of fascinating historical articles from 1996. The first looking forward to 2006, when embedded DRAM is going to eliminate most of the DRAM market, the other looking forward to 1999, and, as usual, completely missing the increase in main memory size over the last three years.
July 15, 1996
As DRAMs move into Gbit densities, it will be possible to put all of the memory needed for a personal computer, plus the processor, on one chip, she said. That won't happen for another decade, but prior to that will come plenty of systems-ranging from PDAs to HDD data buffers to printers-where a relatively small amount of logic will be put onto a relatively large array of memory.
techweb.com
June 17, 1996
There is also an issue of granularity. With the x-16 chips, the minimum memory size would be 32 Mbytes-at least twice the size of mainstream PC shipments today. The granularity problem makes the chips useless in many applications that require smaller amounts of memory, such as frame buffers.
techweb.com
-- Carl |
