Breaking News
Comments
Newest First | Oldest First | Threaded View
rbtbob
User Rank
Rookie
re: Tech Beat: Codewords cut PCM energy needs
rbtbob   7/28/2012 11:24:29 AM
NO RATINGS
Hey! What makes you an expert on algorithms and whether or not they can be effective? :-)

David Brown
User Rank
Rookie
re: Tech Beat: Codewords cut PCM energy needs
David Brown   7/25/2012 10:30:26 AM
NO RATINGS
The whole idea of making this data-dependent is silly and unnecessary. If it were to make sense, then you would be better dealing with the data at a higher level. For example, if you want to store ASCII data efficiently, then compress it first - saving far more than 22%. There is an extremely simple way to get a similar power saving (over 23%), albeit at the cost of extra bits. For each 8-bit byte, you have an additional "invert" bit. For each data read, you use this bit to see if the data bits should be inverted. When writing, you consider both the non-inverted and inverted versions of the data, and choose whichever uses least power. Simple, fast, low-power, and independent of the data.

resistion
User Rank
CEO
re: Tech Beat: Codewords cut PCM energy needs
resistion   7/25/2012 12:54:30 AM
NO RATINGS
I forgot to cite the STT MRAM energy reduction reference: here it is: P. Zhou et al. ICCAD 2009, "Energy Reduction for STT-RAM Using Early Write Termination" (U. of Pittsburgh)

Kristin Lewotsky
User Rank
Blogger
re: Tech Beat: Codewords cut PCM energy needs
Kristin Lewotsky   7/24/2012 10:00:47 PM
NO RATINGS
Thanks for your comments. That's interesting. Based on the paper, I'd understood that having Er/Es greater than 1 was what delivered the energy savings. I'll have to reach out to the authors and see what they say.

Semyon Savransky
User Rank
Rookie
re: Tech Beat: Codewords cut PCM energy needs
Semyon Savransky   7/24/2012 7:41:38 PM
NO RATINGS
The "read before write" approach for is well-known for PCM for a while (at least I recall it from ~ 1985) but effective algorithm can be useful.

resistion
User Rank
CEO
re: Tech Beat: Codewords cut PCM energy needs
resistion   7/24/2012 4:11:01 PM
NO RATINGS
For STT MRAM, Er/Es ~1, and a similar strategy has been proposed.

resistion
User Rank
CEO
re: Tech Beat: Codewords cut PCM energy needs
resistion   7/24/2012 2:51:15 PM
NO RATINGS
But I presume it could work for other Eres/Eset ratios. It's merely an algorithm fit.

Kristin Lewotsky
User Rank
Blogger
re: Tech Beat: Codewords cut PCM energy needs
Kristin Lewotsky   7/24/2012 2:21:13 PM
NO RATINGS
Actually, no—the method works in no small part because the energy required to reset a bit (Er) is roughly twice that of the energy required to set a bit (Es), while the read energy is negligible. It's a nifty bit of work.

resistion
User Rank
CEO
re: Tech Beat: Codewords cut PCM energy needs
resistion   7/24/2012 11:37:59 AM
NO RATINGS
Looks like this approach is fairly generic rather than benefitting PCM specifically.

R G.Neale
User Rank
Rookie
re: Tech Beat: Codewords cut PCM energy needs
R G.Neale   7/24/2012 8:52:19 AM
NO RATINGS
Kristin- The RICE authors also raise the subject of multi-level cell (MLC-PCM) and cite the IBM-MLC. It would certainly be interesting to hear their view on how their memory overhead would be added to IBM’s drift compensating codeword memory overhead and methodology. In that respect, they might also need reminding that the write process for the multi-level cell and some earlier MLC work involves starting with a cell in the reset state and reaching the required data state resistance value by iterative steps. How many more memory codeword solutions to PCM memory problems can be added before in becomes a write never memory (WNM) because there is no room for the data?



EE Life
Frankenstein's Fix, Teardowns, Sideshows, Design Contests, Reader Content & More
Max Maxfield

Creating a Vetinari Clock Using Antique Analog Meters
Max Maxfield
24 comments
As you may recall, the Mighty Hamster (a.k.a. Mike Field) graced my humble office with a visit a couple of weeks ago. (See All Hail the Mighty Hamster.) While he was here, Hamster noticed ...

EDN Staff

11 Summer Vacation Spots for Engineers
EDN Staff
11 comments
This collection of places from technology history, museums, and modern marvels is a roadmap for an engineering adventure that will take you around the world. Here are just a few spots ...

Glen Chenier

Engineers Solve Analog/Digital Problem, Invent Creative Expletives
Glen Chenier
11 comments
- An analog engineer and a digital engineer join forces, use their respective skills, and pull a few bunnies out of a hat to troubleshoot a system with which they are completely ...

Larry Desjardin

Engineers Should Study Finance: 5 Reasons Why
Larry Desjardin
45 comments
I'm a big proponent of engineers learning financial basics. Why? Because engineers are making decisions all the time, in multiple ways. Having a good financial understanding guides these ...

Flash Poll
Top Comments of the Week
Like Us on Facebook
EE Times on Twitter
EE Times Twitter Feed

Datasheets.com Parts Search

185 million searchable parts
(please enter a part number or hit search to begin)