Since I am the Memory Guy I hate learning that I missed something new and cool in the world of memories, but somehow I was unaware of last week’s Memsys conference in Washington DC until a participant notified me on Saturday that his paper: “Reverse Engineering of DRAMs: Row Hammer with Crosshair,” had been given the the best paper award.
Upon looking at the Memsys website it looks like a very intriguing academic conference. about sixty papers were presented in eight interesting sessions:
- Issues in High Performance Computing
- Nonvolatile Main Memories and DRAM Caches, Parts I & II
- Hybrid Memory Cube and Alternative DRAM Channels
- Thinking Outside the Box
- Improving the DRAM Device Architecture
- Issues and Interconnects for 2.5D and 3D Packaging
- Some Amazingly Cool Physical Experiments
in addition to a few apparently-fascinating keynotes.
Fortunately, all of the papers are Continue reading
Naturally, the first question is: “How do they do that?”
To get all the chips into the DIMM format Samsung uses TSV interconnects on the DRAMs. The module’s 36 DRAM packages each contain four 8Gb (1GB) chips, resulting in 144 DRAM chips squeezed into a standard DIMM format. Each package also includes a data buffer chip, making the stack very closely resemble either the High-Bandwidth Memory (HBM) or the Hybrid Memory Cube (HMC).
Since these 36 packages (or worse, 144 DRAM chips) would overload the processor’s address bus, the DIMM uses an RDIMM protocol – the address and control pins are buffered on the DIMM before they reach the DRAM chips, cutting the processor bus loading by an order of magnitude or more. RDIMMs are supported by certain server platforms.
Wiley has recently published a new book by Betty Prince titled Vertical 3D NAND Technologies that is one to consider if you want to bring yourself up to speed on recent research behind today’s and tomorrow’s 3D memory technologies.
For those who haven’t previously encountered Dr. Prince, she is the author of a number of key books covering memory design and holds memory patents written over her 30-year career in the field.
The book provides capsule summaries of over 360 papers and articles from scholarly journals on the subject of 3D memories, including DRAM, NAND flash, and stacked chips.
These papers are organized into Continue reading
SanDisk has introduced an SD Card with a whopping 512 gigabytes of storage. Noting that SD Card capacities have increased by 1,000 times over the past ten years, from 512MB to 512GB, the company says that this product is aimed at professional HD videographers (who can justify its $800 price) allowing them to shoot Raw-format footage without shutting their cameras off, which could potentially allow them to miss a magic moment.
To The Memory Guy this represents an amazing piece of packaging technology. Let’s see why:
In 2003 SanDisk’s 512MB card contained Continue reading
Intel and Micron today announced that the new version of Intel’s Xeon Phi, a highly parallel coprocessor for research applications, will be built using a custom version of Micron’s Hybrid Memory Cube, or HMC.
This is only the second announced application for this new memory product – the first was a Fujitsu supercomputer back in November.
For those who, like me, were unfamiliar with the Xeon Phi, it’s a module that uses high core-count processors for problems that can be solved with high degrees of parallelism. My friend and processor guru Nathan Brookwood tells me Continue reading
On Tuesday the HMC Consortium (that’s short for “Hybrid Memory Cube”) announced that members have agreed upon a specification. The consortium has been moving rapidly, meeting its targets despite the revolutionary nature of the interface.
As a reminder, this technology stacks multiple DRAMs in a single package with a logic chip at the base of the stack that performs all the signalling to the rest of the system. Signals between the DRAMs and logic chip use through-silicon vias (TSVs) as interconnections. This allows the technology to deliver 15 times the performance of DDR3 at only 30% of the power consumption. The Memory Guy first posted about the HMC in late 2011.
The consortium explains that the HMC interface already has 100 adopters, and that a few Continue reading
In a December 1 press release IBM announced that the company will be manufacturing Micron Technology’s Hybrid Memory Cube (HMC) which IBM claims to be “the first commercial CMOS manufacturing technology to employ through-silicon vias (TSVs).”
This device is one that Altera, Intel, Micron, Open Silicon, Samsung, and Xilinx have all presented recently as a plausible solution to the difficulty of increasing the speed of DRAM/processor communications. The Hybrid Memory Cube Consortium (HMCC) website offers a deep dive into the details of the consortium and the technology.