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  1. #1

    Is there a way to write into an sdcard from an android tablet running 4.4.2?

    I've seen a few times the term 'root' in the context of writing into an sdcard and I'm wondering if it means that root privileges must be acquired in order to be able to do so or if it means that the tablet must be made to start up another OS that permits to become root?

    Can someone help me understand which one is to be interpreted as correct?

    Thanks in advance for any info on the above!

  2. #2
    After rooting your tablet you can do it but i will not suggest rooting because you dont know much more about it.


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  3. #3
    Thanks for replying, nilofar_iqbal!

    Does "rooting" a device always mean that the original OS is replaced by another, more permissive OS) probably a Linux version or fork?

    Have you done that already? Any thoughts about it?

    Note: I have one or two cellphones that are working but 'without' service and I'm not considering putting them on service, so they are good candidates for practicing this "obscure" technique of rooting!

    Thanks in advanced for any info on the above!



  4. #4
    If the device are not in use and waste for your side, then you can use rooting for them. If you want to know more about rooting, there is a post in this forum, you can check it.


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  5. #5
    Whether you can write to the SD card on a tablet depends on what you want to write.

    SD cards come formatted as FAT32, and you can store data on them from Android (which writes to the card) with no issues. It's how you get the data on the card in the first place.

    Storing programs on the card is another matter, and does require rooting.

    Android is a Linux system. Linux has an administrative user called root which has the power to change the underlying system. Android devices come with it disabled for normal users. "Rooting" a device simply means making it possible to get root user access and make changes to the underlying system. You aren't installing a new OS. You are unlocking capabilities in the one you have.

    To store programs on the card, the card must have a Linux file system, because FAT32 does not support the needed attributes. After I rooted my tablet, I put the 32GB card I had installed into a reader, plugged it into the PC, and repartitioned it to carve out a 3GB slice formatted as Linux ext4. I put the card back into the device, rebooted, and Android saw it had another ext4 filesystem and mounted it. From there, I could use the freeware Link2SD program to move apps to the card and place a symlink in the root filesystem pointing to them. A few things, like Link2SD itself, must live in device storage, but most things can live on and run from the card.
    ______
    Dennis


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  6. #6
    Thanks for replying to both of you, nilofar_iqbal and DMcCUNNEY!

    First, I spent more than 90 mins reading what a search brought me in here but it was not of great help, maybe you were referring to a specific post that I jump or didn't find.

    Second, your post Dennis, was very clear and helpful! At my system (4.4.2), I've read that writing to the card is disabled by Google. Hav tried it in some ways with different file types but not a chance. I'm almost sure it won't be a choice for ANY app.

    BTW, I've seen the term 'rom', with some liberal forms or variations, but that confuses me; always thought at looking at it of "Read Only Memory" without anything else being an alternative.

    If anything else surfaces that might be of help I'll appreciate it very much!


    Last edited by Benny7440; 02-27-2016 at 03:03 PM.

  7. #7
    Quote Originally Posted by Benny7440 View Post
    Second, your post Dennis, was very clear and helpful! At my system (4.4.2), I've read that writing to the card is disabled by Google. Hav tried it in some ways with different file types but not a chance. I'm almost sure it won't be a choice for ANY app.
    Writing to the card is not disabled by Google. What they did do in KitKat was restrict writing.

    This was a security measure. The problem is that the FAT32 file system used on SD cards has no way to enforce security on a file basis, because it has no place to store things like who owns a file or who has permission to read/write/execute it. Prior to KitKat, any app installed on an Android device could read and write to any part of the card. This was seen as a security hole, so Google made changes to KitKat. Apps were only allowed to read from/write to directories on the card they created and owned. They weren't allowed to look at and change other app's data on the card. This broke various things that expected to be able to do that, like file managers.

    I haven't had a problem on my KitKat device, but it's rooted. My Jellybean device dates from before Google implemented the change.

    How are you trying to write to the card? What are you using to do it?

    BTW, I've seen the term 'rom', with some liberal forms or variations, but that confuses me; always thought at looking at it of "Read Only Memory" without anything else being an alternative.
    ROM does mean "read only memory". In this context, it refers the chip on the device holding things like the boot and base OS code. (On your PC, the BIOS is a ROM chip.) That's intended to be read and executed, but not written to. One of the things Android users do is flash the device to replace the stock ROM with something customized to their needs, but it requires flashing the device from an external source (and voids your warranty.) Most users don't need to do this.

    If anything else surfaces that might be of help I'll appreciate it very much!
    Feel free to ask questions.
    ______
    Dennis



  8. #8
    Sorry, I almost completed my reply but Chrome almost crashed and all the text disappeared. Is this forum saving partial replies at regular times? If yes, how can I retrieve that text back? I looked around for this feature but didn't find anything useful.

    If my text isn't saved anywhere I'll post it back after rulling out the possibility of retrieval.



  9. #9
    Member
    Join Date
    May 2016
    Posts
    10

    Device(s)
    Galaxy Tab A 9.7 '' Galaxy s6 marshmallow
    I recently purchased oa 14gb microsd card gfor my 4 year old gt-p5210 , slid itinto the microsd slot and let the afformentioned device format said microsd card an d in no time was able to install firefox first to main memory then move the application and said related files to my sd card no rooting/hacking required.



  10. #10
    Quote Originally Posted by flipper_droid View Post
    I recently purchased oa 14gb microsd card gfor my 4 year old gt-p5210 , slid itinto the microsd slot and let the afformentioned device format said microsd card an d in no time was able to install firefox first to main memory then move the application and said related files to my sd card no rooting/hacking required.
    I'm missing something.

    The first question is why you formatted the card in the device. microSD cards come formatted as FAT32, and Android can read and write them as is if what is being stored is data. Running programs from the card requires a Linux file system. Why did you format the card in the device, and what file system was created?

    Android devices normally come with some of the built-in flash configured as an internal SD card. And while Android does have an app2sd function to move installed programs to the internal SD card, it doesn't move programs to an external card, even if there is a Linux file system on the card. You need a third party utility for that.

    If you remove the microSD card from your device, does Firefox still run? If it does, it didn't move to where you think it did.
    ______
    Dennis



  11. #11
    Thanks for replying, flipper_droid & DMcCunney!

    The said tablet apparently, died out! Could be the battery or something else. It's still awaiting further analysis. In any case, the information received here is going to be valuable with the next tablet..., at least I hope so!



  12. #12
    I have a Samsung Note 2 phablet running 4.4.2 and the utilities all write to sdcard, and I can even configure apps to use the sdcard by default. Not so on 4.4.4 -->, where some security feature nobbled this in the main Android system.



  13. #13
    Quote Originally Posted by business_kid View Post
    I have a Samsung Note 2 phablet running 4.4.2 and the utilities all write to sdcard, and I can even configure apps to use the sdcard by default. Not so on 4.4.4 -->, where some security feature nobbled this in the main Android system.
    It didn't quite nobble it, but cut down on what could be done.

    The problem is that Android has no way of imposing security on external cards, because external cards are formatted as FAT32 or exFAT, and FAT has no place to store the required metadata like owner or permissions. Any Android app could to access, read from, and write to any area on the card. This was seen as a major security hole, so in 4.4 Kit Kat, permissions were changed. Apps could create directories on a card, read from them, and write to them, but could only access directories they created. They could no access other ares of the card. This caused major heartburn for file managers, which needed to see the entire card.

    It appears to have been manufacturer implementation dependent. There were apps posted in the play store which claimed to address the issue if you had a rooted device. I have tablets running 4.2, 4.4, and 5.0, and never encountered the problem, but mine are all rooted. It's the first thing I do when I get an Android device.
    ______
    Dennis



  14. #14
    Thanks to all that replied above! The said tablet is in fact dead, but the info within this thread is valuable irrespective of that.



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