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Inside Anobit: Why Apple is investing in flash RAM technology

Daniel Eran Dilger

Apple’s investments in acquiring flash RAM expertise and technology appear to be centered around packing more storage capacity into Macs and iOS devices at lower prices, with the same level of component reliability and longevity.
This week, Apple was both reported to be close to acquiring flash RAM chip designer Anobit and engaging in plans to set up a semiconductor development center in Israel, where Anobit is located.

Apple already uses Anobit components in is iOS devices and the MacBook Air. The firm’s unique flash RAM technology, dubbed MSP or “Memory Signal Processing,” is designed to enhance the reliability, performance, efficiency and endurance of flash RAM.

The pros and cons of flash RAM

Unlike DRAM, which stores memory bits using the state of electrical capacitors which must be continuously refreshed with power, NAND flash RAM stores bits using floating gate transistors, which do not need to be continually bathed in current to maintain their state.

This makes Flash RAM more energy efficient during operation, and allows it to retain its information even after the device is shut down. The use of Flash RAM storage in iOS devices and the MacBook Air provides long term storage of software, documents, music and movies without needing a conventional magnetic hard drive for disk storage.

MacBook Air

The use of flash storage not only makes these devices quick to boot up and launch apps, but also slimmer, more battery efficient and less fragile than compatible devices using a conventional hard drive for persistent storage. Particularly on iOS devices, the use of fast flash RAM also limits the need for large amounts of DRAM, further increasing the devices’ battery life.

On the flip side however, flash RAM storage is more expensive compared to disk storage, as well as being less reliable and having a shorter life span. The individual cells of flash RAM chips eventually wear out and stop working reliably, requiring specialized software to manage their use.

Strengthening flash RAM

Earlier this year, Apple incorporated TRIM support in Mac OS X Lion. TRIM is an OS level software technology designed to manage the flakey, short lived nature of flash RAM used in Solid State Drives like the MacBook Air’s (pictured below).

Anobit’s MSP technology attacks the same issues, but does so on firmware level, using sophisticated monitoring of flash RAM cells to accurately determine if they are failing or no longer able to reliably store data. These technologies also enable flash RAM to continue to function longer than previously possible by simply working around failures.

In addition to enabling flash RAM to live longer, MSP also promises to make components faster; it enables data to be pushed to flash RAM at speeds that generate more errors, but can then detect and correct the errors.

Air Teardown 3

Cheaper SSDs and flash RAM

A second primary benefit to the MSP technology is that it makes less expensive types of flash RAM usable for a wider range of applications. Most flash RAM used in high speed storage holds one bit per memory cell, known as SLC or “single level cell” memory.

A cheaper type of flash RAM known as MLC or “multi level cell” can store two bits per memory cell, making it less expensive to manufacture because it has a higher memory density. A primary problem with MLC is that is more prone to error, requiring more sophisticated management to make it useful.

MSP promises to make cheaper MLC memory components as accurate over the same lifespan as conventional SLC, something that would dramatically change how much storage Apple could pack into its devices and computers at the same price. That would have a huge impact on Apple’s ability to compete, as flash RAM storage is a significant part of the bill of materials in the devices it builds.

NAND flash is the second most expensive component of the iPad (after the touchscreen display), according to iSuppli, accounting for around ten percent of its total component cost. For the MacBook Air, 64GB of SSD flash RAM is similarly estimated to be its second most expensive component (again, after the screen) and roughly the same price as its Intel CPU at a similar 10 percent of the total materials cost.

7 comments

1 Mike { 12.14.11 at 9:46 pm }

Well, DRAM does not need to be “bathed” in current. The bit’s state is stored as charge in a tiny and leaky capacitor. It holds its charge just fine but only for a few milliseconds. The DRAM controller cycles through all memory locations, reads them out before they leak away, and rewrites them, every few milliseconds. (No bathing.) Flash stores its charge on a floating gate which is a specific structure that is also a capacitor but leaks very slowly (initially a couple of years but now over 10, so competitive with hard drives) and so it does not need refreshing. But it is a lot slower than DRAM, has a limited lifetime (based on write frequency and how it is managed, as you mention re: TRIM support), and writing is quite a bit more complex than with DRAM.

BTW, I really appreciate your written columns. Hope to see more.

2 rob53 { 12.15.11 at 9:26 am }

I’ve seen other sites saying this acquisition is a threat to Samsung but Anobit doesn’t manufacture chips does it? They only design them and have existing chip manufacturers build them, don’t they? If so, how will this impact Apple’s current supplier(s) of memory chips? Will they opt for less expensive (cost and quality) chips (like you mentioned) from less known suppliers or stay with the big guys? The R&D plant that’s supposedly being built near Anobit in Israel wouldn’t turn into a manufacturing plant would it?

[Apple is beating Samsung in delivering tablets despite the fact that Samsung is manufacturing Apple's SoC chips that go into the iPad. So Apple doesn't immediately need to make its own chips to remain competitive with its own designs. At the same time, it looks likely that Apple will pull manufacturing from Samsung to other suppliers the moment it has the opportunity to do so, leaving Samsung without its Apple subsidy for building chips in volume - Apple buys something like half of Samsung's SoC chip production! - Dan]

3 whmlco { 12.15.11 at 11:07 am }

“MSP promises to make cheaper MLC memory components as accurate over the same lifespan as conventional SLC, something that would dramatically change how much storage Apple could pack into its devices and computers at the same price.”

Well… that’s not bad for an iPod or iPhone, whose life span is probably 4-6 years at best, but for a notebook I’d prefer that they use the new controllers on SLC in order to make them more reliable and last longer.

4 adobephile { 12.16.11 at 4:59 am }

@Mike
“reads them out before they leak away, and rewrites them, every few milliseconds. (No bathing.)”
How does this rewriting not occur without the flow of current? “Every few milliseconds” seems to qualify as continuous. So, what’s your definition of bathing?

5 Mike { 12.16.11 at 8:05 am }

@adobephile: milliseconds is eons in semiconductors. Most operations happen in nanoseconds so the refresh is, comparatively, at a positively glacial pace.

6 adobephile { 12.16.11 at 8:08 am }

@Mike: Quit splitting electronic hairs, you nerd, and concede the point that net current flow in DRAM is more than in flash memory.

7 gus2000 { 12.16.11 at 11:17 am }

Wait, now electrons have hairs!!? You quantum physicists make me nuts.

I put a SSD drive into my laptop, mostly because the HD access light was pretty much on continuously thanks to whole-drive encryption + constant virus scanning. I was worried that paging space would shred my SSD’s lifespan, so I did the math: if I wrote to my SSD continuously, at the full speed of the SATA bus, it would take almost 2 years for me exceed the number of rated write/erase cycles.

I actually don’t find my laptop “faster” with the SSD during normal processing, it simply doesn’t suffer the horrendous bottlenecks of it’s spinning mechanical cousins. A noticeable speed increase would certainly make the premium price far more attractive.

SSD is where the post-PC world is headed, anyway. Phones, tablets, PMPs, and ultra-thin notebooks all use SSD technology. That’s where Apple has the bulk of it’s sales, so there’s quite the incentive for this investment.

I might even open my wallet for a new desktop if I could get a TB-sized SSD at Thunderbolt speeds…

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