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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repoman27 - Wednesday, November 27, 2013 - link
Right, totally different issue though.However, if your internal battery was twice the volume to begin with, you would still have more than half a charge left at the same point that the normal one was nearly empty. You wouldn't have to pay for and carry around a separate battery and charger. It would be always be with your phone, never forgotten, and less likely to get lost or damaged. You wouldn't have to power down, switch batteries and boot back up again. The whole setup would weigh less, consume fewer resources, be more portable and provide more than twice the juice all the time. Encouraging OEMs to sell certain device models with much larger batteries that are a couple mm thicker is by far the better solution, even if those batteries are sealed. I believe the RAZR MAXX demonstrated that this could be a rather popular option.
Of course there will always be corner cases where even that isn't enough to get through a situation where one is unable to charge for an extended period. At a certain point, carrying a ginormous battery (or stack of smaller ones) around all the time is less attractive than the alternatives, i.e. remembering to plug in when you can, learning to become a better opportunistic charger, or carrying a solar or hand-winding charger.
I honestly think there is a phobia associated with the idea of having a dead phone battery and nowhere to charge it. I can imagine that swappable batteries do more to allay that fear for those that have it, but from a logical standpoint it's not the best way to solve the problem.
Hairs_ - Thursday, November 28, 2013 - link
People may upgrade smartphones, but that doesn't mean their device has to go in the bin. A phone with replaceable battery/cover/storage allows for the device to be passed on to children, friends, relatives etc.repoman27 - Monday, December 2, 2013 - link
Actually, even smartphones with sealed batteries that lack microSD card slots can be passed on to others. In fact, judging by the second hand market, some such models retain value significantly better than their user replaceable battery and upgradable storage contemporaries.Of course none of this changes the observed average service life of mobile phones. Cracked screens, exposure to liquids, and operator subsidies which encourage buyers to believe that all new smartphones cost less than $200 are what cause most handsets to end up in the bin prematurely.
Dentons - Tuesday, November 26, 2013 - link
No Anand, the microSD ship hasn't sailed. And yes, you should absolutely penalize devices for not having these features.Every best selling Smart Phone (in every major size category) for the past many cycles, including the current cycle, has both microSD expansion and a user-swappable battery. Every. Single. One.
Many of us will gladly trade a few grams of weight and a single mm of thickness for those features. Really, that's all we're talking about. A single mm of thickness, a few grams of weight. It's incredibly odd that you find such a trade-off to be so objectionable and unrealistic.
As many readers have observed, Anand and Brian seem to have become overt advocates for the mobile industry, rather than being advocates for their readers.
One can understand why the marketing people in the mobile companies are willing to sacrifice features in favor of looks. It's difficult to understand why Andantech should embrace fashion over function.
Listen to your readers. We want these features. Given the maturity of the mobile space, there will certainly be device makers willing to cater to our needs.
In addition, it's a tremendous cop-out that Anandtech doesn't penalize devices for not having these features. You regularly penalize devices for their outer casing, but for real, actual, hardware features like microSD and swappable batteries. No words - pro or con. No benchmarks of microSD transfer speed.
Please stop spending so much time fetishizing metal cases and focus on these actual features.
Tanclearas - Tuesday, November 26, 2013 - link
Although you argue about manufacturers making design/cost decisions based around "the mainstream" usage of smartphones, for some reason Brian wants to believe that "the mainstream" wants manufacturers to spend more space and cost on implementing a high end camera. In virtually every podcast (when they actually happen), he complains incessantly about the cameras and thinks everyone else out there actually cares like he does. For some reason he thinks his complaints are valid, while dismissing complaints about removable batteries and microSD cards. That is pretty conceited to believe your personal opinion is "right".I have stated for some time that microSD is a requirement as long as manufacturers are shipping phones with 8 to 16GB of storage. It's hard to believe that people as well-traveled as Anand and Brian can actually depend on cloud storage. I guess you're only travelling to areas with non-roaming data or dependable WiFi. Take a trip across North America into areas like northern Canada, or eastern Kentucky. The cloud doesn't exist there. I actually purchased a Nexus 5, but only because there was a 32GB model. 32GB is the sweet spot for me where I can store enough locally to not have to depend on the cloud, but I'm not going to try to argue that it is enough for everyone. I agree with others that microSD can go away once 32GB becomes the entry, and we aren't charged $50 for each extra 16GB.
As for the argument about "extra battery life" vs "removable battery", I am willing to bet that you are talking about a low-single-digit percentage difference in battery life. It's not like there's any evidence even in your own reviews to show that there was a significant increase in battery life for phone models that utilize a non-removable battery. In terms of cost savings, once again you are talking about fractions of a dollar. These are not things being done for the ultimate benefit of the end user. They are being done strictly to shave off every last possible penny from the BOM. My particular usage model is such that I do not absolutely require a removable battery, but again I would never argue that my usage model is "the right one, and everyone else is wrong".
Ego and arrogance of the site owners/editors/writers is exactly why I stopped visiting Toms Hardware and HardOCP. Brian is walking a very fine line right now.
ruzveh - Tuesday, November 26, 2013 - link
removable battery is a must as we cant live without hanging issue, short battery life and bigger capacity battery replacement.azazel1024 - Tuesday, November 26, 2013 - link
I think the battery replaceable vs not replaceable makes sense in the conclusion.I disagree completely on the micro SD card slot.
It is easy enough to design it intelligently so it doesn't particularly compromise the design of the phone. For instance, have in in the side/top/bottom of the phone behind a small flap/door. I've seen a number of designs where this works fine and likely wouldn't/doesn't compromise the internal layout of the device.
I also think it is a mistake to not set it up as a seperate drive in the storage space.
I think most people are smart enough to figure out that one storage space is on the phone itself and one is the removable micro SD card.
There are many advantages to removable storage. One of which is cheaper storage. Another is many manufacturers don't have options other than 16/32GB. Or if they do have more options, they are all expensive.
There are other perks too, like if you are shooting with a REAL camera, you can use a micro SD card in an SD card adapter and then pop the card out and stick it in your phone to upload the files, as an example. Or if you want to use a nice high speed micro SD card, you can pop it out, stick it in a USB 3.0 card reader and toss a ton of stuff on it real fast and then stick it back in your phone. Instead of having to physically connect your phone to your computer or do it over Wifi. A few songs, a few pictures a small movie, it probably doesn't make much difference. Want to load 50GB of movies to your 64GB micro SD card though before a big trip? I am thinking the difference in transfer speeds would be much appreciated...and you also might not want to sit there for an hour with your phone physically tethered to your computer transfering the files.
I know the post was about phones, but I think this goes double for tablets. ALL DEVICES SHOULD HAVE AT LEAST A MICRO SD CARD SLOT! TABLETS SHOULD HAVE AT LEAST A MICRO SD CARD SLOT AND PREFERABLY A FULL SD CARD SLOT!
geniekid - Tuesday, November 26, 2013 - link
Removable batteries I understand. The trade-off of a solid, unibody shell is a big trade-off for the benefit of being able to swap out batteries. Plus, I believe companies are incentivized to put in the best battery they can into their flagships because this is something that many people focus on.MicroSD (removable storage), on the other hand, I completely disagree with. You can keep a unibody case without sacrificing too much. And, companies usually charge a high premium for higher amounts of storage because reviews hardly ever focus on the amount of storage you're getting for your money. Arguably the kind of person who would spend money to buy the 64GB edition of a phone/tablet over the 32GB is comfortable with managing multiple drives and slower I/O of microSD.
haukionkannel - Tuesday, November 26, 2013 - link
Yeas and no :-)I know many people who can not use the drive d: because they just can not... in PC environment. Too comples. If you thik that it is even a little bit harder in phone environment, then it is not usefull feature...
Anyone in this forum know how to use drive d: in PC and external storage in their mobilephone, but we are not the big important majority...
What I won't understand is that when OS could show all storages as on one big storage to user who really don't understand aenything about storage system, why it is not implemented.
Normally the main reason is that user can not know where his or her pictures are, if there are multible storages... *sigh* is is hard to compete agains the minimum factor reality....
agent2099 - Tuesday, November 26, 2013 - link
don't iphones, the 'epitome' of industrial design, have removable SIMs. This is as much of a "tradeoff" as putting in a micro sd slot no? If they can have a removable sim and maintain build quality, they can have a removable SD, and this goes for Android also. I can understand how a batter can compromise the structure, but a micro SD card will not provide the same sacrifice in build.