A Post about Removable Storage, Removable Batteries and Smartphones
by Anand Lal Shimpi & Brian Klug on November 25, 2013 8:40 PM EST- Posted in
- Smartphones
- Mobile
There's been a lot of talk lately about our position on removable storage and removable batteries in smartphones. Most of the discussion has centered around what we've said in podcasts or alluded to in reviews, so we figured it's a good time to have the complete discussion in one central location.
Let's get through the basics first:
All else being equal, removable storage and user replaceable batteries aren't inherently bad things. In fact, they can offer major benefits to end users.
The key phrase however is "all else being equal". This is where the tradeoff comes in. On the battery front, the tradeoff is very similar to what we saw happen in notebooks. The move away from removable batteries allows for better use of internal volume, which in turn increases the size of battery you can include at the same device size. There are potential build quality benefits here as well since the manufacturer doesn't need to deal with building a solid feeling removable door/back of some sort. That's not to say that unibody designs inherently feel better, it's just that they can be. The tradeoff for removable vs. integrated battery is one of battery capacity/battery life on a single charge. Would you rather have a longer lasting battery or a shorter one with the ability the swap out batteries? The bulk of the market seems to prefer the former, which is what we saw in notebooks as well (hence the transition away from removable batteries in notebooks). This isn't to say that some users don't prefer having a removable battery and are fine carrying multiple batteries, it's just that the trend has been away from that and a big part of the trend is set based on usage models observed by the manufacturers. Note that we also don't penalize manufacturers for choosing one way or another in our reviews.
The tradeoffs are simple with an internal battery, the OEM doesn't need to include a rigid support structure on the battery to prevent bending, and doesn't need to replicate complicated battery protection circuitry, and can play with alternative 3D structures (so called stacked batteries) for the battery and mainboard as well. Personally, I'd rather have something that lasts longer on a single charge and makes better use of internal volume as that offers the best form factor/battery life tradeoff (not to mention that I'm unlikely to carry a stack of charged batteries with me). It took a while for this to sink in, but Brian's recommendation to charge opportunistically finally clicked with me. I used to delay charging my smartphone battery until it dropped below a certain level and I absolutely needed to, but plugging in opportunistically is a change I've made lately that really makes a lot of sense to me now.
The argument against removable storage is a similar one. There's the question of where to put the microSD card slot, and if you stick it behind a removable door you do run into the same potential tradeoff vs. build quality and usable volume for things like an integrated battery. I suspect this is why it's so common to see microSD card slots used on devices that also have removable batteries - once you make the tradeoff, it makes sense to exploit it as much as possible.
There's more to discuss when it comes to microSD storage however. First there's the OS integration discussion. Google's official stance on this appears to be that multiple storage volumes that are user managed is confusing to the end user. It's important to note that this is an argument targeted at improving mainstream usage. Here Google (like Apple), is trying to avoid the whole C-drive vs. D-drive confusion that exists within the traditional PC market. In fact, if you pay attention, a lot of the decisions driving these new mobile platforms are motivated by a desire to correct "mistakes" or remove painpoints from the traditional PC user experience. There are of course software workarounds to combining multiple types of storage into a single volume, but you only have to look at the issues with SSD caching on the PC to see what doing so across performance boundaries can do to things. Apple and Google have all officially settled on a single storage device exposed as a single pool of storage, so anything above and beyond that requires 3rd party OEM intervention.
The physical impact as well as the lack of sanctioned OS support are what will keep microSD out of a lot of flagship devices.
In the Android space, OEMs use microSD card slots as a way to differentiate - which is one of the things that makes Android so popular globally, the ability to target across usage models. The NAND inside your smarpthone/tablet and in your microSD card is built similarly, however internal NAND should be higher endurance/more reliable as any unexpected failures here will cause a device RMA, whereas microSD card failure is a much smaller exchange. The key word here is should, as I'm sure there are tradeoffs/cost optimizations made on this front as well.
The performance discussion also can't be ignored. Remember that a single NAND die isn't particularly fast, it's the parallel access of multiple NAND die that gives us good performance. Here you're just going to be space limited in a microSD card. Internal NAND should also be better optimized for random IO performance (that should word again), although we've definitely seen a broad spectrum of implementation in Android smartphones (thankfully it is getting better). The best SoC vendors will actually integrate proper SSD/NAND controllers into their SoCs, which can provide a huge performance/endurance advantage over any external controller. Remember the early days of SSDs on the PC? The controllers that get stuffed into microSD cards, USB sticks, etc... are going to be even worse. If you're relying on microSD cards for storage, try to keep accesses to large block sequentials. Avoid filling the drive with small files and you should be ok.
I fully accept that large file, slow access storage can work on microSD cards. Things like movies or music that are streamed at a constant, and relatively low datarate are about the only things you'll want to stick on these devices (again presuming you have good backups elsewhere).
I feel like a lot of the demand for microSD support stems from the fact that internal storage capacity was viewed as a way to cost optimize the platform as well as drive margins up on upgrades. Until recently, IO performance measurement wasn't much of a thing in mobile. You'd see complaints about display, but OEMs are always looking for areas to save cost - if users aren't going to complain about the quality/size/speed of internal storage, why not sacrifice a bit there and placate by including a microSD card slot? Unfortunately the problem with that solution is the OEM is off the hook for providing the best internal storage option, and you end up with a device that just has mediocre storage across the board.
What we really need to see here are 32/64/128GB configurations, with a rational increase in price between steps. Remember high-end MLC NAND pricing is down below $0.80/GB, even if you assume a healthy margin for the OEM we're talking about ~$50 per 32GB upgrade for high-speed, high-endurance internal NAND. Sacrifice on margin a bit and the pricing can easily be $25 - $35 per 32GB upgrade.
Ultimately this is where the position comes from. MicroSD cards themselves represent a performance/endurance tradeoff, there is potentially a physical tradeoff (nerfing a unibody design, and once you go down that path you can also lose internal volume for battery use) and without Google's support we'll never see them used in flagship Nexus devices. There's nothing inherently wrong with the use of microSD as an external storage option, but by and large that ship has sailed. Manufacturers tend to make design decisions around what they believe will sell, and for many the requirement for removable storage just isn't high up on the list. Similar to our position on removable batteries, devices aren't penalized in our reviews for having/not-having a removable microSD card slot.
Once you start looking at it through the lens of a manufacturer trying to balance build quality, internal volume optimization and the need for external storage, it becomes a simpler decision to ditch the slot. Particularly on mobile devices where some sort of a cloud connection is implied, leveraging the network for mass storage makes sense. This brings up a separate discussion about mobile network operators and usage based billing, but the solution there is operator revolution.
I'm personally more interested in seeing the price of internal storage decrease, and the performance increase. We stand to gain a lot more from advocating that manufacturers move to higher capacities at lower price points and to start taking random IO performance more seriously.
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NeoteriX - Wednesday, November 27, 2013 - link
The article is snarky and condescending, but perhaps it is frustration because many of the commenters and folks who raise this as an issue miss the point.All the points you raise are largely correct (though I would disagree with the "greater capacity in total, as the article shows, within a phone's original design spec (that part is key), a nonremovable battery wins on capacity), but they still inevitably miss the point.
Engineering or design or making a product is always about trading off and balancing competing considerations. Like I said before, the majority of the points you raise are true, but you feature no discussion of their drawbacks. Just because the drawbacks are trivial to you does not mean they are trivial in the marketing and sales of a phone. Furthermore, when determining what design compromises to make, phone manufacturers will look to their target market and what the market wants.
In this regard, it appears that the market has largely spoken. While a minority of hardcore enthusiasts/hobbyists prefer the removable battery and microSD (and I think they are great too), Apple made a gamble a long time ago that people would largely not miss them... and by the vast sales of iOS devices (and we are talking total user base, not phone to phone as the GS3/GS4 have been quite competitive), it is evident that consumers largely do not miss these feature and will take smaller size and cleaner/more attractive design.
AnitaPeterson - Friday, November 29, 2013 - link
Who cares about Apple? Apple is relentlessly promoting a view of the personal computer which is never opened, upgraded or in any way modified by the user. And they push for the same thing in the phone arena.I would have thought AT members are precisely the kind of people who like to upgrade their computers, open them up, tinker with them, and so on. We may or might not represent a user majority, but that's besides the point.
Anand and Brian are trying to sell us the moral equivalent of a completely closed computer system, in which all the components are soldered inside a sealed shell. Which is ironic, considering that if computers would have been like this from the beginning, Anand would not have had a site at all.
chizow - Monday, November 25, 2013 - link
Anand it is sad to see you reiterating the same biased viewpoint as Brian with regard to removable batteries and microSD cards.I really think you are both out of line here as I can guarantee you the overwhelming % of your readers do not get free smart phones to review to the point it becomes tedium for you, or have product review budgets that allow for top-of-the-line, storage to the max, price-be-damned flagship units without exception. Dismissing these important, differentiating features that clearly add value to a product does your readership a great disservice, imo.
-Battery: Would I rather have an insignificant 15% more battery life that tethers me to an outlet throughout the day, or 100% or more swappable battery life with the ability to charge 2 batteries simultaneously (1 on phone, 1 on charger)? I would go with 2 batteries, especially if I needed 24 hours of uninterrupted usage while on business travel or on vacation. 1 battery on me, charging when I can, 1 battery charging in the office, hotel, etc. Best of both worlds.
-MicroSD: Would I like to spend 50-100% ($100-$200 on contract) more on a phone for 48GB more storage? Or would I rather spend $35-50 for 64GB more storage that is compatible with thousands of other devices also? Sure it is slower, but I know for a fact you are a proponent of this very same heterogenous storage configuration on desktop PCs (fast SSD + slower HDD), why do you feel smartphone users are too stupid to grasp and adopt this simple usage pattern?
-Flagship devices and microSD cards: I keep seeing you and Brian repeat microSD going the way of the dodo, but all I see are more devices adopting it to alienate the few that choose not to include a microSD slot. Virtually all non-Apple or non-Google devices in their respective markets are adding microSD, especially in the tablet space (both Android and Windows devices). In the flagship smartphone market, you just did a review on the HTC One Max that deviated from previous HTC designs by *ADDING* microSD. Do you think the 2014 successor to the HTC One will have a microSD slot or not?
In summary, I am really not sure what your motives are when you interject your own preferences over those of your readership. Failing to empathize with your readers only serves to alienate when you should be speaking up for what we want. Take a step back and think about it, if you didn't review tech for a living, would you want to pay these exorbitant prices for something that for all intents and purposes, does just as well for a fraction of the price?
jwcalla - Tuesday, November 26, 2013 - link
It's just the opinion of a couple of guys on the internet.chizow - Tuesday, November 26, 2013 - link
Normally I'd be inclined to agree, but in this case these two guys on the internet do have a greater voice and direct access to mfgs and OEMs. It really is a shame they take their own insulated viewpoints and usage patterns as gospel.NeoteriX - Wednesday, November 27, 2013 - link
Honestly, it looks like they are merely expressing the preferences of the larger market, and not the more minority enthusiast/hobbyist market.chizow - Wednesday, November 27, 2013 - link
Which is again, a flawed analysis if you are starting with the entire smartphone market. Why concern yourself with what entry-level users prefer on a flagship device that's only targeting the top 15-20% of the market? Similarly, why bother adding enthusiast features like K chips, Turbo, SLI etc. if you are going to claim only a tiny % of the CPU/GPU market is interested in these features?If they want to speak for the mass market, make that clear and leave that discussion out of high-end flagship device reviews. But we know that's not the case, we know AT can't be bothered to review anything less than upper tier smartphones, anything less wouldn't justify Klug reaching into his pocket and pulling out his SIM card removal tool.
NeoteriX - Wednesday, November 27, 2013 - link
The mass market is buying high-end flagship mobile devices though, that's the thing. Apple's annual iteration of the iPhone is both mass-market and is unquestionably high end (the PowerVR GPU used in iOS devices dominated the GPUs available in Android devices for years, until possibly recently, and even then, it's a push, and the same goes for the CPU in terms of performance and efficiency--the latest Apple A7 SoC with its 64-bit ISA and 6-wide design).And it appears the market has spoken, Apple devices (iPhones, iPads, iPod Touches) have a huge portion of the market, and Android devices are split amongst those with removable batteries and MicroSD cards.
I won't bother to research/estimate how many there are in each camp, but suffice it to say that if not a majority of devices lack SD slots/batteries, then at least half do, and that's probably a safe enough reason not to penalize companies that decide to omit them. ("Where reasonable minds differ....")
And it seems that thinness is just as much an important "high end" *and* mass market spec as removable batteries and SD cards.
chizow - Wednesday, November 27, 2013 - link
You will never see Apple products described as flagship, they are decidedly mid-range devices carrying a huge luxury tax with 1 or 2 features that justify that tax to their targeted end-users (ex: "Retina" screen resolution, A7 SoC in latest iPhone).The rest of the device is 1 or 2 generations back, if not more. Apple's lustre is not it's cutting-edge flagship status, it is it's ease of use which is precisely the market that is disinterested in advanced features like microSD and removable batteries and obviously not the one targeted by flagship device makers.
So no, the mass market isn't buying flagship phones, they are buying free with contract phones or last year's iPhone offered free or at a discount. Of course Apple has a huge marketshare as the 1st smartphone maker but that share has also dwindled and never catered to users who demanded more functionality to begin with.
Once you take Apple out of the equation, you see who dominates the high-end flagship smartphone market. Samsung's S and Note series flagships are clearly head of the class. Even though HTC's One was often reviewed as well or better than the S4, it still lagged in sales with the lack of microSD and removable battery cited as major reasons as to why it lost to the S4. And now, as a reactionary measure, HTC released the One Max with removable battery and microSD slot, coincidence? I think not.
Also, if you are going to start bringing in other aesthetics or usable features, then surely you must bring screen size into the discussion? Sure thinness matters, but so does screen size right? ;)
NeoteriX - Thursday, November 28, 2013 - link
If you cannot concede that Apple iOS devices are state of the art and are by far flagship technology smartphones, we can't have a conversation. In multiple, multiple places in Android and iOS reviews, the AnandTech staff have pointed out the superiority of iPhone hardware, and Android developers are just beginning to catch up in some areas (and still fall short in others). And this is coming from a guy who has never owned an iPhone and exclusively uses Android devices. When the Tegra 3 was released, it only had 1/5th the GPU power of the current iOS SoC. The current Apple A7 blows away any other ARM SoC and even outclasses Intel x86 Atom CPUs with its super wide instruction crunching design.So seriously, if you can't admit that 1) Apple offers class leading designs and hardware, 2) that they (currently) sell and (historically) have sold incredibly well, and 3) lack a removable battery and microSD, then you're not arguing from a position of intellectual honesty.
Finally, the Galaxy S series and the Note have done quite well, this is true, but when you look at the whole ecosystem, they're far from a majority or even half of devices. Definitely not a "mandate" by consumers, and so, one would be justified in not penalizing mfrs in reviews for not having one.