Need help from other Android Users: What is your Android Memory scheme.

[Hook]

The phone memory can show up through a file manager app on the phone assuming the phone is rooted. Its not just a different file system, but a partition with stricter permissions that require superuser access. Once you get down to this level in Android, you're basically dealing with Unix/Linux drive management.

Internal Phone Memory acts like a boot partition. Everything that the phone needs to boot up has to go there. That's why apps with widgets either have to be installed on the Phone memory or have parts of them installed on Phone Memory. Stuff like the contacts app has to go here. Various agent services for apps, used for background notifications, syncs and other maintenance activity, also goes into there. That's why when an app is transferable to the SD, some parts actually remain in the boot partition/phone memory. The principle is similar to the C: drive in a PC.

All my devices are rooted and I use root explorer-- I was talking more about making a storage area appear as a drive on Windows XP. The System Panel app does a nice job of breaking down the different actual and logical storage areas and the file system used. The funny thing is, Root Explorer can create symlinks, but they are nearly useless because both main user storage areas are vfat file systems. I assume, because Root Explorer has them, folks out there must be creating ext3 partitions on thier internal and external memory cards, but I'm not quite up to wrestling with that.

[Stryker]

On my EVO LTE, my internal memory is painted like that. So, even though I have an sd card, my device shows as having 2 external storage areas.

Takes some getting used to.

This is becoming more common on the newer devices, which is why some don't have external storage slots.

Mobile post via Tapatalk

[Hook]

On my EVO LTE, my internal memory is painted like that. So, even though I have an sd card, my device shows as having 2 external storage areas.

Takes some getting used to.

This is becoming more common on the newer devices, which is why some don't have external storage slots.

Mobile post via Tapatalk

Thanks for popping in. I should have posted that I pretty much have my answers, although new data is always apprecated. The key "problem" is that, at least for Gingerbread, there is only one mount point for external storage. I don't have ICS or JB, so it is hard to be sure, but I believe this has not yet changed. There is different ways that this gets dealt with, but by far the most common scheme I have run across is to treat the internal flash memory as the SD Card (ie, the USB memory is mounted at the system defined SDCARD mount point) and make the actual sd card a subfolder to the USB memory. I have seen many hacks for this scheme --there is one that works for my SP5-- but none of them involve creating two mount points. It might be possible if the user storage were formatted, say, Ext3 rather than Fat32. I think that is part of it, but FAT32 is what makes the memory usable in Windows Explorer. I have heard the Galaxy Nexus doesn't have USB memory, is not formatted Fat32 and is only mountable to Windows by MTP, so there are a number of schemes out there. However, creating two different user storage mount points and letting APS2SD select which to move apps to does not seem to be in the picture.

[Varjak]

The Evo LTE is ICS, isn't it?

[SGosnell]

In Linux, any drive, partition of a drive, or folder in a partition, can be mounted anywhere. Android is slightly tweaked Linux. The phone manufacturer can partition the memory any way it wants, so there can be any amount of phone memory, and any amount of the internal flash drive used as "SD card". On my Transformer Prime, the external SD cards are actually mounted under the root filesystem, NOT under the SD Card. On my Samsung Galaxy S phone, the external SD is mounted as a subdirectory of the internal SD. How it's done is entirely dependent on the manufacturer, and it can be done any way at all. Linux mount points are not the same as Windows drives in any way. With Linux, /boot can be an entirely separate drive, a partition on any drive, or a subdirectory of any drive. It's usually a subdirectory of the main hard drive, but it doesn't need to be. With phones, it's almost always on the main flash drive, which is partitioned in any of several ways.

In short, there is not one answer to the original question. It all depends on how the manufacturer sets the system up.

[Hook]

In Linux, any drive, partition of a drive, or folder in a partition, can be mounted anywhere. Android is slightly tweaked Linux. The phone manufacturer can partition the memory any way it wants, so there can be any amount of phone memory, and any amount of the internal flash drive used as "SD card". On my Transformer Prime, the external SD cards are actually mounted under the root filesystem, NOT under the SD Card. On my Samsung Galaxy S phone, the external SD is mounted as a subdirectory of the internal SD. How it's done is entirely dependent on the manufacturer, and it can be done any way at all. Linux mount points are not the same as Windows drives in any way. With Linux, /boot can be an entirely separate drive, a partition on any drive, or a subdirectory of any drive. It's usually a subdirectory of the main hard drive, but it doesn't need to be. With phones, it's almost always on the main flash drive, which is partitioned in any of several ways.

In short, there is not one answer to the original question. It all depends on how the manufacturer sets the system up.

I understand what you are saying. I have used Linux quite a bit myself, though I am by no means an expert. And it is nice to know that at least ASUS is doing different things with their tablets. I'm not, however, sure that with the phones it is entirely the manufacturers (and I mean, literally, I don't know). I have gotten the impression from some sources, at least for phones, that Google has in fact imposed some kind of limitation here (or, maybe, not yet enabled the ability to move past the limitation) and, as far as I can tell, there in no Android Phone that uses two mount points for user storage nor allows Aps2sd to select among possible destinations. My pet theory is that it allows Android developers to not care whether there is an SD card slot or not, but that's not based on any data.

My questions (there wasn't just one) were originally posed to simply find out how wide spread this situation was across different Android makes and models.

[Varjak]

Very good points Stan; but why then do so many manufacturers (if not all) seem to choose the clunky, sub-directory arrangement? I hope someone (preferably one of the majors like Samsung or HTC twig to this and fix it). Or better yet, Google ought to change it.

[SGosnell]

AFAIK, they do it because it's easy. There is no difference, from an OS standpoint, in an Asus tablet or a Samsung phone. The OS allows mounting any drive to any mount point, so I don't believe it has anything at all to do with an OS limitation, it's just convenience. Each manufacturer tweaks Android to some extent, and most seem to do whatever is quick and easy. The partitioning of the internal flash drive is certainly done by the manufacturer, so that can vary a lot. If you can get root on your phone, you should be able to edit the fstab file and mount the external SD card wherever you want. It does take some knowledge, but I see no reason why you couldn't, if you really want to and are willing to put in the time to learn. XDA Developers may provide some help in this, although I haven't actually looked. The external SD mount point just hasn't been a concern for me.

[Hook]

AFAIK, they do it because it's easy. There is no difference, from an OS standpoint, in an Asus tablet or a Samsung phone. The OS allows mounting any drive to any mount point, so I don't believe it has anything at all to do with an OS limitation, it's just convenience. Each manufacturer tweaks Android to some extent, and most seem to do whatever is quick and easy. The partitioning of the internal flash drive is certainly done by the manufacturer, so that can vary a lot. If you can get root on your phone, you should be able to edit the fstab file and mount the external SD card wherever you want. It does take some knowledge, but I see no reason why you couldn't, if you really want to and are willing to put in the time to learn. XDA Developers may provide some help in this, although I haven't actually looked. The external SD mount point just hasn't been a concern for me.

Here is the thread in which Raspy and I explored the issue.

How To Get The Samsung Galaxy Player 5 (US) to Mount The External SD Card as the Default SD Card


I found and fstab that worked to switch which, USB memory or SD card were mounted at /SDCARD using an FSTAB file, but I could never find anyone creating an FSTAB file to mount both. I'm sure it is more than you want to bother with, but if you have any insights, they would be welcome. I've been all over XDA.

[internetpilot]

This "problem" has actually existed for quite a while -- on the tablet side of things.

My Acer Iconia A500 has 16GB of memory and then I put a 32GB SD card in it. Everything that normally would default to the external SD card on a phone ended up in the internal memory on my tablet -- Titanium Backup backups, Nandroid backups, file managers would mount the internal memory as the external SD card, onboard still and video cameras record to internal, etc. In Honeycomb (and at least the ICS from Acer that I upgraded to) there is no provision for "moving apps" to the SD card. It was quite quirky dealing with it when I first got the tablet, but now most of the developers have corrected that problem with their apps, but it's still not possible to move an app from internal to external memory like I can with my HTC EVO 4G. Relatively few developers really wrote dedicated Honeycomb apps, so I think it's a combination of the tablets moving on to ICS, and the phones catching up to the tablet platform in terms of internal memory that resulted in the problem getting at least mostly solved for me.

Things are REALLY weird with my two kids' Nook Color tablets. I still don't know exactly what's going on with the internal memory, partitions, etc., and with CyanogenMod7 feature of automatically moving apps to the SD card, I really have no idea if it's actually doing that or if it's just moving it to a different internal memory partition...?