You didn't have to be a memory expert to come away with some
key insights from last week's Flash
Memory Summit. The conference had some important messages for anyone
designing systems-on-chip, or for that matter any kind of electronic product
that has a memory subsystem.
The conference was a three-day event, and Denali Software,
now part of Cadence, was a platinum sponsor. The following report is drawn from
a plenary session, two keynotes, and an analyst panel that took place Thursday.
In a blog
posting yesterday, I wrote about an entertaining keynote given by Steve
Here are some key takeaways for OEMs and SoC designers:
1. Memory may be the
most important part of your system. Ed Doller, chief memory systems
architect at Micron Technology, noted in a
keynote that most consumers today care more about Gigabytes than Gigahertz.
This is because of insatiable consumer demand for increasingly sophisticated
applications. Doller said that a 500 Gbyte solid state drive (SSD) for mobile
devices is a possibility by the middle of the decade, but he reminded listeners
that it can "only" hold 40 to 50 Blu-ray movies.
2. You have to
understand the end-user applications to choose a memory subsystem.
Different types of applications have different memory needs, and the list of
available memory technologies will grow over the next few years. Doller said:
"It is absolutely critical to understand usage conditions. If we understand the
end application and understand the technology capability, I'm pretty sure we
can build the lowest cost solution out there." This is very consistent with the
3. Deep collaboration
between OEMs and memory provides is becoming crucial. This follows from the
second point. "For OEMs, the key message is that we need close collaboration,"
Doller said. "Make sure you help us figure out what types of applications these
[memory] technologies are going into."
4. Existing memory
technologies are running into limits. Analysts noted that NAND flash will
surpass DRAM as the leading memory technology, but at the "Life Beyond Flash"
plenary session, speakers noted that NAND flash doesn't scale well with new
geometries. Performance, power, reliability, and/or endurance can fall short of
system needs. "Memory performance is becoming a key bottleneck for system
performance, and none of the existing technologies can really deliver that
performance that's needed," said Farhad Tabrizi, CEO of STT-RAM provider Grandis.
5. It's time to stop
counting electrons. Alan Fitzgerald, CTO of Smart
Modular Technologies, noted that current memory technologies use
electron-based storage cells, while likely NAND and DRAM replacements "measure
resistance through a substrate that's been altered." The most-frequently
mentioned new technologies in the plenary session were phase-charge memory
(PCM), magnetoresistive RAM (MRAM), and spin torque transfer RAM (STT-RAM).
6. New memory
technologies will change system architecture. Many existing memory architectures
include both NAND and DRAM, and require data to be moved between the two. PCM
and STT-RAM both promise to replace DRAM (initially) and possibly NAND flash
(down the road). Mark Greenberg, product marketing manager at Cadence, noted
that PCM is already replacing DRAM in some applications. PCM cost needs to drop
to take on NAND flash.
Likewise, Tabrizi said that Grandis STT-RAM will aim to
replace DRAM first, and then potentially replace NAND flash and embedded SRAM.
If STT-RAM does all this, it will remove a lot of bussing, and cause a
fundamental rethinking of computer architectures.
7. New memory
technologies will spur the use of SSD. Solid state drives have come on more
slowly than many people expected, and one problem with NAND in SSDs is that bit
error rates increase at lower geometries. PCM may help by lowering bit-error
rates and improving density and performance, Fitzgerald said.
8. No, the iPhone
does not use SSD. Alan Niebel, analyst at Web-Feet Research, said that SSD
uses a standard hard disk drive interface, which the iPhone does not. Instead,
it uses embedded flash drive (EFD). Meanwhile, Jeff Janukowicz of IDC said SSD
revenues were up 59% in 2009. How many industries can make that claim in such
an awful year?
You can read about several other Flash Memory Summit
sessions in Steve Leibson's Denali