NAND – The Memory Guy Blog

Where is Micron’s QuantX?

For more than a year The Memory Guy has been fielding questions about Micron’s QuantX products.

First announced at the 2016 Flash Memory Summit, this brand name has been assigned to Micron SSDs and DIMMs that use the Intel/Micron 3D XPoint Memory. Originally QuantX products were scheduled to ship in 2017, but Micron is currently projecting availability in 2019. My clients wonder why there have been these delays, and why Micron is not more actively marketing this product.

The simple answer is that it doesn’t make financial sense for Micron to ship these products at this time.

Within two weeks of the first announcement of 3D XPoint Memory, at the 2015 Flash Memory Summit, I knew and explained that the technology would take two years or more to reach manufacturing cost parity with DRAM, even though Intel and Micron loudly proclaimed that it was ten times denser than DRAM. This density advantage should eventually allow XPoint manufacturing costs to drop below DRAM costs, but any new technology, and even old technologies that are in low-volume production, suffer a decided scale disadvantage against DRAM, which sells close Continue reading “Where is Micron’s QuantX?”

Why DRAM is Threatened by SSDs

Conventional wisdom holds that SSDs will someday displace all HDDs, but in reality SSDs are proving to be more of a challenge to the DRAM market than to the HDD market.

Right now you are probably reviewing the date of this post to make sure it’s not dated April 1. I assure you that this is the truth. To understand it, though, you must look at a computer as a computer architect would, or, in other words, the way that an application program sees the memory/storage hierarchy.

To the application program there is no HDD and memory, there is only memory. The Virtual Memory system, a part of the operating system, hides the difference between the two by moving code and data into DRAM as it is needed and back onto the HDD when it is no longer important, without telling the application program that it is moving anything around. I like to tell people that the DRAM makes the HDD look fast, and the HDD makes the DRAM look big.

If you think of the DRAM as something that makes the HDD look fast, then additional DRAM should help to make the Continue reading “Why DRAM is Threatened by SSDs”

Micron and Intel to End NAND Flash JV

It came as a surprise to the Memory Guy on Monday to receive a press release from Micron indicating that Intel and Micron had decided to end their NAND flash partnership.

This agreement, which was begun in 2006, helped the two companies to aggressively ramp into the NAND flash market by combining their resources. NAND flash makers (as well as DRAM makers) need to make very substantial capital investments to participate in the market, and that’s not easy for a new entrant. Micron at that time was a very small NAND flash maker, and Intel wasn’t involved in the NAND flash market at all, so neither was in a position to succeed. By combining their resources the companies were able to become important contributors to the market.

The agreement initially appeared to be modeled after the very successful joint venture that Toshiba and SanDisk enjoyed. Each company would contribute half of the JV’s capital investment, and the same designs would be used to make both companies’ chips.

Over time Intel found itself in a familiar Continue reading “Micron and Intel to End NAND Flash JV”

How 3D NAND Shrinks ECC Requirements

Error Correction Codes, ECC, are not only important to today’s NAND flash market, but they have been a cause of concern to NAND users for a number of years. The Memory Guy has been intending for some time to write a low-level primer on ECC, and I am finally getting it done!

Why is ECC necessary on NAND flash, yet it’s not used for other memory technologies? The simple answer is that NAND’s purpose is to be the absolute cheapest memory on the market, and one way to achieve the lowest-possible cost is to relax the standards for data integrity — to allow bit errors every so often. This technique has been used for a long time in both communications channels and in hard disk drives. Data communication systems can transfer more data using less bandwidth and a weaker signal over longer distances if they use error correction to restore distorted data. Hard disk drives can pack more bits onto a platter if the bits don’t all have to work right. These markets (and probably certain others) have invested a lot of money in ECC research and development, and as a result ECC today is a very well-developed science.

Denali Software published a nice Continue reading “How 3D NAND Shrinks ECC Requirements”

Memory Issues in Space & Medical Applications

The Memory Guy was recently asked about using memories in a satellite. What would be a good technology to use in a space application?

The problem with space is that there is a lot of radiation. Radiation on the earth’s surface is lower because it is stopped by the atmosphere, but in space there is an abundance of radiation that interferes with most semiconductors. Radiation is also a concern in certain medical applications where a memory must maintain its contents while undergoing sterilization through irradiation. Experiments on conventional flash memories have shown data loss at only 2% of the Continue reading “Memory Issues in Space & Medical Applications”

Obama Honors SanDisk Co-Founder

SanDisk co-founder Eli Harari was awarded the National Medal of Technology and Innovation on November 20 by President Obama. The medal, which was bestowed upon Dr. Harari in a White House ceremony, is the United States’ highest honor for scientific and technological achievement, and recognizes those whose lasting contributions have created a greater understanding of the world and improved the lives of many.

Harari co-founded SanDisk more that 25 years ago with the vision that flash memory would be used to store data in mobile products, a vision that initially took seed in photography in the 1990s, and has since become the fastest-growing Continue reading “Obama Honors SanDisk Co-Founder”

Is Apple Losing Dollars to Save a Few Cents?

An article in a recent issue of Business Korea posits that Apple may be having trouble stemming from the company’s adoption of TLC flash in it’s new iPhone 6.

The article states:

considering that technical defects mainly occur in the 128GB version of the iPhone 6 Plus, there might be a problem in the controller IC of triple-level cell (TLC) NAND flash.

The problem has led to numerous warranty replacements and the looming prospects of a recall.

(Note that Continue reading “Is Apple Losing Dollars to Save a Few Cents?”

Fundamentals of Memory – Free Online Course

Some time ago The Memory Guy was asked by Numonyx (later acquired by Micron) to put together an online course for EE Times on memory technologies, explaining how each one works and where it is used.

Although the course was very well received, I never posted a link to it on The Memory Guy blog. This post is intended to correct that error.

The course runs 75 minutes and covers the basics of DRAM, non-volatile RAM, SRAM, NAND flash, NOR flash, mask ROM, and EEPROM. It explains each technology’s advances in size, cost and performance, leading up to the development of Continue reading “Fundamentals of Memory – Free Online Course”

Is the DRAM Market Entering a Shortage?

Long-term clients of mine, even those dating back to my decade at Dataquest in the 1990s, are familiar with the concept that spot prices behave differently during a shortage. When there is too much DRAM spot prices remain below contract prices, because OEMs who bought too much product clear their inventory at quarter end (and other times) by selling at a loss.

During a shortage the opposite is true: OEMS find that they can’t get as much DRAM as they wanted through their contract sources, so they shop for the balance on the spot market. Since there are more buyers than sellers, spot prices invariably raise higher than contract prices.

When the prices change from one state of affairs to the other then it is safe to assume that Continue reading “Is the DRAM Market Entering a Shortage?”

What is a “Multilayer Cell”?

From time to time I get questions from investors in the memory business asking: “What is a multilayer cell?”

The answer is: “There is no such thing: It’s a misstatement.”

The term “MLC” has, by a number of people, been mistranslated to “multi-layer cell.” The misunderstanding appears to have originated in the financial community. People in the flash memory business never use the term at all.

Yes, we talk about MLC, but to us the term means “multilevel cell”.

A multilevel cell is a cell that uses varying voltage levels to represent different states. With four voltage levels the resulting four states on a single cell can be turned into Continue reading “What is a “Multilayer Cell”?”