I'd seen speculation that Apple was going to drop $500M on Anobit over the past few weeks. Ars Technica also published a piece believing the acquisition to be true, and it looks like the office of Israel's Prime Minister tweeted a bit of a confirmation (Anobit is based in Israel). I looked at Anobit's extremely vague technology descriptions and dug a bit into their patent portfolio to better understand Apple's motivation behind the acquisition.

If you've followed our SSD coverage over the years you'll know that NAND endurance was a valid concern in the early days of consumer SSDs. When Intel arrived on the scene with the X25-M, its controller technology included a number of enhancements to work around common NAND errors and degradation over time. Other companies followed suit and eventually NAND error correction and reliability were major selling points of SSD controllers. 

More recently, Micron announced that it would be baking ECC technology into a separate line of NAND called Clear NAND. Micron believes that in the future if you don't have access to a controller that does significant ECC or a NAND solution that includes active ECC technology that you won't be able to deliver competitive NAND based storage.

Today not much of this is necessary for consumer SSDs, even forthcoming 20nm IMFT NAND is still good for 3000 - 5000 program/erase cycles, which is more than enough for client use. However if you're using greater than 2-bit-per-cell MLC (e.g. 3-bit-per-cell MLC) then the need for better error correction is more urgent. 

Smartphones and tablets need not-insignificant amounts of NAND (16 - 64GB for high end devices today, twice that next year). The cost of this NAND isn't all that much in the grand scheme of things, at the low end you're looking at several dollars and at the high end the cost is more than offset by the ridiculous increase in device pricing. The problem is not at the high end but what happens when you start selling cheaper phones. If we are indeed heading toward a future where mainstream computing is done on smartphones, then we're also headed toward a future where all smartphones need dozens of GBs of NAND on-board. That includes the ultra cheap devices as well as the high-end flagships.

Price sensitivity in these devices means that the high grade, compute NAND used in SSDs isn't what gets used by smartphone manufacturers. Instead you get the mid-grade stuff at best, but more likely you find some slow, 3-bit-per-cell NAND in the cheaper devices. There's no room (physically or budget) for sweet SSD controllers by Intel, Marvell or SandForce, thus NAND management is typically handled by an eMMC controller (or something similar) integrated into the phone/tablet's applications processor (e.g. Snapdragon, Tegra 3, A5, etc...).

Cheaper MLC NAND trades off endurance and performance for cost. How do you get to have your cake and eat it too? Well if you're set on using cheaper NAND, you have to do more processing on the controller side to clean up the data you're reading back from the shaky NAND. This isn't a problem on day one, but it becomes an issue over the months/years as you've written more data to the NAND. Cells have to be periodically refreshed, storing redundant data becomes necessary, the controller must recover/reconstruct lost data, etc... Every company has their approach to dealing with these problems. It was the first solutions to these problems that allowed consumer SSDs to use cheaper MLC NAND, and the solution to the smartphone/tablet issue is of a similar nature. 

Anobit appears to be applying a lot of signal processing techniques in addition to ECC to address the issue of NAND reliability and data retention. In its patents there are mentions of periodically refreshing cells whose voltages may have drifted, exploiting some of the behaviors of adjacent cells and generally trying to deal with the things that happen to NAND once it's been worn considerably.

Through all of these efforts, Anobit is promising significant improvements in NAND longevity and reliability. At the high end Anobit promises 50,000 p/e cycles out of consumer grade MLC NAND, and in the smartphone/tablet space Anobit promises more useful lifespan out of 3-bit-per-cell MLC NAND. 

As for why Apple would want Anobit, the potential reasons are huge. First the company was a cheap buy for Apple, although expensive if you look at the market as a whole (SandForce went for ~$370M). If all Apple gains from Anobit is bringing some smart NAND folks on staff the cost won't really break the bank. The obvious fit is to integrate Anobit's technology into Apple's ARM based SoCs. These SoCs already talk to NAND directly and integrating better error correction/reliability processing into the SoC just makes sense. For all we know, Apple already uses this technology in its SoCs and is simply acquiring Anobit to make it more difficult for competing SoC makers to do the same. Integration and assimilating value are the cornerstones of building a good SoC, this move makes sense (assuming Anobit's technology is actually good).

Note that if you look at the graph above, continuing to use 3-bit-per-cell NAND requires more than just standard ECC. It's clear Apple wants to continue to use value NAND in its devices, Anobit is simply a guarantee that it will be able to do so in the future.

At the other end of the spectrum, Anobit has enough technology to build a decent SSD controller (it already appears to do so for enterprise SSDs). If Apple wanted to really commoditize SSDs, it could use Anobit to produce its own SSD controllers. Apple would then simply buy NAND from memory vendors instead of the present day solution of buying a complete SSD solution for its Macs. This would shave a not insignificant portion of the BOM (bill of materials) cost of SSD production, which would help Apple transition to SSDs in more of its systems. This is more of a longshot as far as I'm concerned as, at least today, there are a lot of low-cost, competent controller makers in the SSD space.

Apple has been internalizing many of the pieces used in its SoCs over the past few years. It even owns a 9.5% stake in Imagination Technologies, the GPU company that supplies IP for Apple's SoCs. While I understand Apple's motives from the standpoint of a mostly vertically integrated hardware/software entity, there is a bit of defocus that comes with going too far down this path. I'm still not sold on the idea of Apple becoming a full fledged silicon vendor. It makes sense today, but as these SoCs become hugely complex, billion+ transistor devices I'm unsure if Apple wants to assume even more of the burden involved in bringing one of those parts to market. 

Until we get to that point however, acquistions like Anobit come relatively cheaply for Apple and should help guarantee NAND reliability and performance for its more cost sensitive products (particularly as NAND geometries continue to shrink going forward). If Anobit's technology is up to muster, it should also mean that Apple will be able to continue to scale up NAND capacities in its devices without resorting to increasing device costs. NAND is ultimately driven by Moore's Law, however reliability doesn't follow the same curve by default. Integration of Anobit-like technologies are necessary to ensure it does.



View All Comments

  • melgross - Wednesday, December 21, 2011 - link

    Of course, it's also possible that the technology is really better. If so, and I can't imagine that Apple didn't do it's due diligence here as they are a conservative company, then if others need to go somewhere else, they may not have anywhere else to go that offers the same advantages.

    And if Apple can shave points off their expenses, that gives them a marketing and sales advantage, as they may be able to offer devices with the same amount of flash for less, or more for the same.
  • nsiboro - Wednesday, December 21, 2011 - link

    Thanks Anand.

    This type of article got you guys loads of brownie points and my continual support for another 10+ years.
  • ckryan - Wednesday, December 21, 2011 - link

    Anobit already has an embedded flash controller, the MSP2025 and an Enterprise GENESIS SSD.

    I'd seen new reports stating that Apple was already using Anobit IP/products in the iPhone, iPad, and MBA -- the last is the most doubtful as the MBA uses Toshiba or Samsung SSDs. The MSP2025 is listed as supporting all 2xnm NAND types (MLC and TLC, SLC). It is also listed as having a maximum transfer rate of 666MB/s.
  • ckryan - Wednesday, December 21, 2011 - link

    If the technology works as advertised, it would be a huge deal. I speculate that the Anobit acquisition was more to keep the Android coalition away from the technology and intellectual property, but you could theoretically have a much cheaper TLC SSD with MLC like endurance. That would open the door for cheap solid-state bulk storage too, not to mention decent MLC acting more like SLC in terms of endurance. I doubt the Anobit technologies can overcome the fact that it still take longer to program non-SLC NAND types, but at least you can get the endurance.

    There is another "super ECC" with an expiring patent in 2015, but it's unclear whether that would be a worthy substitute or not, and I don't know much about it.
  • jabberwolf - Thursday, December 22, 2011 - link

    Edurance doesnt matter for regular computers and laptops.
    Other SSDs are faster and the P/E cycles of regular consumer use would not exceed that of an average competitor.

    Apple wants the proprietary controller patents, for the simply reason of being able to use it as "proprietary".

    And I'm kinda pissed because the endurance WOULD matter for those of us in the corporate server industry that want fast SSD with IOPS.,, that DO have many many more write/erase cycles than your average user over 5 years.
  • foxyshadis - Thursday, December 29, 2011 - link

    Why would anyone want TLC if they wanted IOPS? It's still faster than disk at random access, sure, but it's slower than MLC, which is already much slower than the SLC that nearly all enterprise systems are made with. Only SLC can even keep up with disk for sequential access. The whole point of this technology is just to make them as reliable as SLC, not to make them faster (if anything, they'll be slightly slower with advanced ECC). Reply
  • iwod - Wednesday, December 21, 2011 - link

    I think it depends on How much is apple already paying Anobit for using the MSP, ( For Memory Signal Processing ), If they are paying up to a 10 Million per year for using it then buying it makes much sense. Reply
  • jabberwolf - Thursday, December 22, 2011 - link

    The technology for Anobit has little or nothing to do with consumer based things like the MBA or any regular computer. In fact Anobit SSDs are slower in comparison to others out there with much higher IOPS abilities.

    The only think hat Anobit has is a technology which is awesome for LONG LIFE - but you would never see the difference for regular computers, only in heave erase and write cycles with servers.

    The only benefit from this that Apple could gain would be:
    1- that it now has owns a SEPARAPE controller interface... one that is not the standard.

    I this way, they can ensure that their precious OSX cannot be virtualizes as this seems to be a trend in the future. Apple wants to be able to run virtualized VMs of Windows and Linux but they wont dare allow their own OS to be virtualized. The only way they can maintain this legally, and physically, is to tie their OS to hardware requirements. Hardware requirements ONLY owned by Apple.

    This is kinda sad as Apple is building a wall around their fenced garden .. and in doing so, using a really good technology that would be greatly benefcial to the server side industry.
  • CeriseCogburn - Tuesday, June 5, 2012 - link

    Well, that looks like it makes APPL extremely selfish, and holding back technology as a whole for the masses. Anti-competitive, selfish, plotting, and caring only about itself and it's own dastardly self centered plans.

    Don't worry, though, it's kingpin on the stock market now, the dollars and cents talking heads worship it, and follow it like a boy licking a candy cane, so "bad press" is an absolutely forbidden thing.

    No one will mention their dirty little selfish plot that holds back the entire world.
  • Electrofreak - Friday, December 23, 2011 - link

    Last I checked (http://forum.xda-developers.com/archive/index.php/... in January of this year, I had 7 bad blocks on the NAND of my Epic 4G. Now, just a couple weeks under a year later, I still have only 7 bad blocks.

    $ su
    # export PATH=/data/local/bin:$PATH
    # cat /proc/L*/bmlinfo
    FSR VERSION: FSR_1.2.1p1_b139_RTM
    minor position size units id
    1: 0x00000000-0x00040000 0x00040000 1 0
    2: 0x00040000-0x00080000 0x00040000 1 1
    3: 0x00080000-0x00a80000 0x00a00000 40 20
    4: 0x00a80000-0x00bc0000 0x00140000 5 3
    5: 0x00bc0000-0x00d00000 0x00140000 5 4
    6: 0x00d00000-0x01200000 0x00500000 20 21
    7: 0x01200000-0x01980000 0x00780000 30 6
    8: 0x01980000-0x02100000 0x00780000 30 7
    9: 0x02100000-0x12d80000 0x10c80000 1074 22
    10: 0x12d80000-0x32f80000 0x20200000 2056 23
    11: 0x32f80000-0x3de80000 0x0af00000 700 24
    12: 0x3de80000-0x3eb00000 0x00c80000 50 11

    (0)(0) bad mapping information
    No BadUnit RsvUnit
    0: 198 4090
    1: 1217 4089
    2: 1683 4088
    3: 2988 4087
    4: 3193 4086
    5: 3505 4085
    6: 3530 4084
    7: 3876 4083

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