High capacity microSD cards and Android


The whole ‘does an Android phone need expandable storage’ debate has been raging for decades and it’s been a real roller-coaster of a journey. one year Samsung’s flagships have microSD card slots, the next year they don’t, then assist is lower back once more. Up and down, up and down. Google in no way appears to want to include microSD card support in its Nexus line, but the individual OEMs who manufacture the Nexus devices do consist of aid on other handsets they make!

In case you do have a phone that does encompass a microSD card then one of the first questions you are probably to ask is that this: what’s the highest capacity microSD card that I’m able to use on my cellphone? And it is a superb query, but the answer won’t be as simple as you had been hoping. To get to the bottom of this we are going to need to take a look at the one-of-a-kind microSD requirements, the exceptional document systems supported by Android and by using desktop OSes like windows & OS X, plus we can need to take a peek into the murky world of patents.

MicroSD cards and the SD affiliation

Allow’s begin with the fundamentals. The requirements for SD cards and microSD cards are described with the aid of the SD affiliation. It was set up in 2000 by using Panasonic, SanDisk and Toshiba to broaden and promote reminiscence card storage requirements. essentially the SD affiliation makes positive all SD related generation (readers, cards and so forth) are compatible. At gift there are three standards with regards to the capability of SD and microSD cards:

Type of cardMax CapacityFile SystemBackwards Compatibility

So essentially the unique SD card standard supported playing cards up to 2GB. Then came SDHC which extended the potential to 32GB after which more these days the SDXC standard became launched to enhance the potential to 2TB. all of the requirements are backwards well matched, this means that a device with an SDXC aid can use all 3 forms of SD card, but a tool with an SDHC guide can simplest read SDHC and SD, but no longer SDXC.

When it comes to handsets you can have noticed that some OEMs will say something like this, “expandable storage via microSD card up to 32GB.” what that probable manner is that device has an SDHC well-matched card reader. Technically any Android tool which helps SDXC should advertise “expandable storage thru microSD card up to 2TB.” however because 2TB microSD playing cards don’t exist (but), maximum OEMs will say something like “expandable storage via microSD card up to 128GB” where the “128GB” bit could be an extraordinary capacity depending on whilst the device become launched and what’s the best modern-day microSD ability that is commercially available.

FAT32, exFAT and Microsoft

As well as defining the physical characteristics of the memory cards, the SD affiliation additionally recommends how statistics are stored in the cards. If you imagine that the SD card is a block of storage space, any device that wants to examine a file from that block desires to know where in the report starts off evolved at the block and where it ends. It desires which will locate that information from the file name (truly the whole direction call) and it also wishes to know some records approximately the file’s permissions, and so on. The way the files are organized on a storage device is managed via the file system. There are lots of different file structures. On home windows you are probably the use of NTFS, on OS X it’s miles HFS+ and on Linux most probably ext4.

back in the past due Nineteen Seventies Microsoft produced its first version of a file system known as fat (file Allocation table). It changed into initially evolved for use on floppy disks, however over time it has determined its manner onto tough disks, DVDs, USB flash drives and SD cards. It becomes the default file system for home windows until home windows XP. There had been numerous extraordinary variations of fat (mainly primarily based around the scale of the table factors inside the allocation desk). these extraordinary variations are acknowledged by using the number of bits that can be saved in each table place. The authentic fats used 8-bit entries, and is today referred to as FAT8, then came FAT12, and with the inclusion of a hard disk in the IBM computer AT we were given FAT16. For windows ninety-five OSR2 Microsoft released FAT32.

The prolonged record Allocation table (exFAT) file machine is every other Microsoft design.

As you can see from the desk above, FAT32 is the recommended file system for SD and SDHC cards. however, FAT32 does have some boundaries including a maximum file length of 4GB. at the same time as the concept of a 4GB file was likely, not possible to people putting in windows 95 (from floppy or 650MB CDROM), these days recording excessive great video can without problems create a 4GB record. to conquer those boundaries a new filesystem became followed, exFAT.

The extended file Allocation table (exFAT) file gadget is any other Microsoft design, that changed into first brought in 2006 as a part of Windows CE 6.0. It allows for files which might be larger than 4GB and it turned into followed by means of the SD Card association because of the default file system for SDXC cards. For the testing phase beneath I bought a 128GB microSD card from Kingston, and with the aid of default, it was formatted the use of exFAT.

because FAT32 and exFAT belong to Microsoft here we, in reality, locate how Microsoft is managing to make billions of greenbacks from Android. If an aftermarket desires to use FAT32 or exFAT it desires to pay a license rate to Microsoft. I am no longer one for conspiracy theories, but it’s far “thrilling” how the SD affiliation used exFAT for SDXC. FAT32 is probably comprehensible, it became the dominant enterprise fashionable, but exFAT become not utilized by everybody other than Microsoft, then all of an unexpected every telephone OEM, virtual digicam maker, media participant producer may need to pay Microsoft a royalty to help SDXC and exFAT…

curiously home windows won’t format SD cards bigger than 32GB the usage of FAT32. however, it’s miles feasible using 1/3 birthday party equipment. in case you try to layout a 64GB (or larger) USB flash pressure or SD card beneath windows, you’ll select between NTFS and exFAT.

Adoptable storage

due to the fact we are talking approximately microSD cards, it’s far well worth mentioning adoptable storage. as soon as a microSD has been inserted into a smartphone, the query arises, how have to Android use it? The most effective way is for the more storage for use for media like photographs, tune or videos, and dealt with in a similar manner to a USB flash power on windows. The smartphone isn’t dependent on the card in any way and may perform without or with the cardboard. This allows the consumer the freedom of taking away the card and the use of it on a laptop and then popping it again into the smartphone while wanted.

however, it’d additionally be nice to have the option to use the more storage as though it turned into an internal storage and set up apps onto it, plus save app information on it. This has been possible in the beyond with the diverse “pass to SD” mechanisms, however, it has one most important pitfall, protection. If I move an app over to the SD card and begin storing my private information on that card then I open myself up to facts robbery. If someone gets rid of the SD card out of your cellphone they best want to plug the cardboard into an SD card reader on a laptop or pc to get access to your unencrypted records.

Android 6.0 Marshmallow delivered the concept of adopting outside storage so that it acts like internal storage. when a microSD card is adopted, it’s far formatted and encrypted to simplest work with that device. Now you could correctly save both apps and personal information on the cardboard. One thrilling function of adoptable storage is that it isn’t restricted to 2TB like SDXC, however, can honestly use media as much as nine Zettabytes… Now, in which did I positioned that nine Zettabyte microSD card, I understand it is right here somewhere!!!

Flash drives and USB OTG

Although we have been talking about  SD cards, it’s far interesting to word that a whole lot of our dialogue additionally applies to USB flash drives. Many Android gadgets can connect with USB flash drives through a micro USB to USB OTG adapter. Like SD cards, USB flash drives can be formatted as both (but no longer restricted to) FAT32 or as exFAT. additionally the restrictions approximately record length and so forth practice similarly to FAT32 formatted USB flash drives.

As I cited in advance, Windows won’t format large USB drives as FAT32, you need to select exFAT, as opposed to NTFS, if you need to have any hazard of the drive working with Android. Having said all that, my 128GB USB flash force (from Lexar) got here pre-formatted as FAT32, because of this it wasn’t formatted the usage of the built-in windows format device!

Testing a few gadgets

to check the support for FAT32, exFAT, and SDXC I got hold of a 128GB microSD card and a 128GB USB flash drive. Then I tried to use them on an expansion of various devices from the Raspberry Pi to a Sony television in conjunction with lots of Android gadgets. this is what I found out:

USB flash drive formatted exFAT

For this check and the subsequent one, I took my 128GB USB flash drive, copied some documents onto it and linked it to an expansion of gadgets, the usage of an OTG adapter whilst necessary (i.e. for the Android phones).

let’s start with what didn’t paintings. The Raspberry Pi jogging Linux won’t read exFAT files and neither does a laptop walking Linux. this is because of the licensing troubles round exFAT, it belongs to Microsoft and whilst there are a few open supply exFAT drivers they aren’t within the mainstream for felony motives. but the exFAT formatted USB drive is identified by using Chrome OS going for walks on my ARM-based totally Samsung Chromebook. As you’ll expect Google and Microsoft have a huge ranging set of patent and pass licensing deals (which likely cowl FAT32 and exFAT). They even recently agreed to prevent complaining to the regulators approximately each different.

There had been two different devices which I attempted which didn’t work with exFAT. One was my Sony Bravia (non-Android) television and the alternative became a Motorola Moto G (2015) jogging CM 12. all the different gadgets I examined work first-class along with the Samsung Galaxy S7, Kindle hearth, Samsung Galaxy note area (AKA note 4 area), Asus Zenfone 2, OPPO F1 Plus, and Huawei Mate 8.

USB flash drive formatted FAT32

I reformatted the USB drive as FAT32 (using a 3rd birthday celebration tool, as home windows won’t do it) and attempted it once more on the gadgets that had issues with exFAT. the good news is that the Raspberry Pi and my pc going for walks Ubuntu were able to read the USB drive without any trouble. which is to be predicted virtually. additionally, my Sony tv had no trouble with the FAT32 formatted USB drive. I did a short couple of assessments to make certain that a number of the Android devices ought to nonetheless examine the flash drive the use of an OTG cable, and they may. The handiest tool that also didn’t need to examine the force changed into the Moto G running CM 12.

microSD card formatted exFAT

For the following assessments, I used a 128GB SDXC microSD card. For the first test, it becomes formatted as exFAT. I copied over a few files after which tested the cardboard in a selection of various gadgets. starting with what didn’t paintings, the SD card wasn’t diagnosed by the Xiaomi RedMi notice 2, the ZTE big name 2 nor the Elephone P6000. The latter are strolling Android 4.four. KitKat.

however the card labored perfectly on a group of different Android gadgets along with the Huawei P9, the Samsung Galaxy S7, the Huawei Mate eight, the Galaxy be aware area, the Moto G (2015) going for walks CM 12, the ASUS Zenfone 2, the OPPO F1 Plus, Samsung Galaxy S3 Neo, and my Samsung Chromebook.

microSD card formatted FAT32

I modified the format of the microSD to FAT32 and tried the devices that didn’t formally recognize the card and the coolest news is that they worked! The Xiaomi RedMi note 2, ZTE megastar 2, and the Elephone P6000 all mounted the cardboard and were able to examine the files on it. As a side take a look at, I reformatted the card again as exFAT a placed it again into the Xiaomi RedMi observe 2. As earlier than the cardboard wasn’t recognized, however, there was an option to reformat it. once I did the RedMi observe 2 reformatted it as FAT32 and it labored!

I attempted the FAT32 formatted card on a Raspberry Pi three. The Pi was able to boot and set up Raspbian (through NOOBS) from the cardboard with none problems.


So what does all this mean? essentially it appears that evidently support for exFAT is the stumbling block for a few gadgets. For a tool to officially assist large SDXC cards, it has to be able to read and write to exFAT formatted media. at some point of my assessments, I discovered several devices that don’t help exFAT and so don’t formally help SDXC cards over 32GB. however in every case wherein a device couldn’t get entry to the 128GB card with exFAT, I was capable of reformating the card as FAT32 and it worked, even in phones that had been 2 years antique and running Android 4.4 KitKat.

bottom line, if you have a microSD card fit in your cellphone it’s going to possibly work with huge (>32GB) SDXC cards and if it doesn’t then a quick reformat of the card to FAT32 will probably solve your troubles. As for 2TB cards, once they do finally pop out, your cell phone needs to aid those as properly!

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