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[tkenimer]

I have downloaded several programs (apps) to my AirPad.  I attempted to move as many of them as I could to the SD card, but most of them can't be moved.  In fact, I found that the last few apps that I downloaded couldn't be moved and I began to suspect that some resource was used up.  I found that I have 0.00B of available NAND flash out of a total of 2.56GB and I'm not sure if downloading the apps caused the problem, or what to do about it, or even if it is a problem.

When I type df it shows 2G available, 2G used, and 0 free for /mnt/storage and only 4Mbytes free out of 202Mbytes for /system.  Strangely, the files and directories in /system have a date of 1969-12-31 at 18:00, which is just before the start of UNIX clock time - 1970-01-01.
When I type ls -l /mnt/storage it shows about 30Mbytes of files and three directories - LOST.DIR, sdcard, and Android.  The sdcard has a date of 1969-12-31, while the other two are 2011-01-01.

I am able to use the AirPad and it seems to be responsive enough for what I am currently using it for.  Most of the apps that I am currently using work.

I don't know how the operating system and apps use the NAND flash.  There is an option under Storage Settings to erase the NAND flash, but, since I don't know what is stored there, I haven't tried that.  I have 227MB of internal storage and 5.67GB (out of 8GB) of SD space. 

I don't have any data or apps on the AirPad or the SD card that can't be easily replaced.

In addition to fixing the problem(s), I would like to know how the AirPad (or Android) utilizes the various types of memory (internal, NAND, and SD) and what I should do to best utilize it in the future.  So, if someone knows this I would appreciate if you could write up how it works and how to best use it.  Or, provide a link to a write-up.  Thanks...

[Immortal]

You can try app2sd application it can move the applications from the internal storage to the sd and vice versa

[tkenimer]

Thanks for the reply.  I was using ApptoSD and it moved some apps, then it stopped moving the apps.  So, I took your advice and downloaded App2SD and it does exactly the same thing, except that it did prompt me to free up some cache first, which ApptoSD didn't do.  I tried moving just one single app at a time and tried moving two different apps.  Both attempts failed.  The page layout to move the app was exactly the same on both programs.  Then it failed to move the app and displayed exactly the same message.  So, both programs appear to be different front-ends to the same code that does the move with App2SD having the added feature of allowing you to clear cache first.

I suspect that I may have to uninstall some apps to free up enough memory resources to allow App?SD to do it's thing.  It may buffer an internal copy of the app that it is moving or build some sort of large memory map and not have enough free memory to do that. 

It is curious that I could download and run another app though, if that's the case.  That's why I would like to know how AirPad/Android utilizes the three types of memory.  The SD is obviously mass storage since the pad works without an SD.  It must also use part of the NAND flash as mass storage.  And it needs enough information to find programs stored on the SD.

I wonder if the NAND can be increased to 4 or 8Gbyte.  Hmmmm  It's tiny and probably a multi-layer board.  I have piggy-backed memory chips on larger computers, but it required adding a jumper and sometimes even cutting traces on the motherboard.  Probably very risky on something this small.  Does anyone know if a schematic and board layout diagram are available?

[YB]

there are pictures of the inside on AlienDev.com

[Tesla]

I also posted about memory usage, but never got an official answer.

The best I can tell ... it has 4 gigs of internal flash memory which it calls NAND Memory. Over a gig of that has been partitioned away and it holds an "image" of the OS and initial factory load (in case you do the "Factory Restore" option).

That leaves us with about 2.5 gigs of free space. There is a folder called /sdcard that is uses for random storage (almost like a fake SD card). If you add a 8gig mini-SDHC card, it will now say you have 10.5gigs of space. I suggest you create a folder called "Media_Storage" on the mini-SDHC card (with folders like Music, Videos, etc. inside it). Only copy your personal media here to leave the internal 2.5gigs of internal space available for apps. I'm pretty sure the internal flash memory is the fastest. Your mini-SD card is going to be class 4 or 6 unless you pay a lot more for it.

When you install apps, they seem to throw data and config files just about anywhere they want to. You can really tell Android is just a phone OS and immature... not many rules or order ... but it works.

[tkenimer]

Michael,

Thanks.  I really enjoyed you web site, articles, and snippets.  From picture 105242 of the AirPad it looks like the tiny power plug could be strapped to pins 1 and 4 of one or both of the USB recepticals for charging using an USB, but I couldn't tell if USB pins 1 and 4 were connected to circuit board traces or just soldered to pads and used for mechanical mounts.  Were you able to tell which chips were the NAND memory and get their part number(s)?

Tesla,

I think you may be right about the way the memory is used.  I was curious to find the /sdcard directory and then find that the real SD card is mounted under /mnt.  I expected it to be either under /mnt or /media, depending on the flavor of Linux that Android is built on.  I did see some large media files that I will either move to the SD or delete.  I haven't fully explored the directories yet.  I decided to get an HDMI cable and attach a USB keyboard so I can see the output better and type faster before I carry on digging. 

[tkenimer]

I resolved the problem and didn't have to wait for the keyboard and HDMI cable to arrive.

It's as you said, Tesla.  I had copied all kinds of stuff into the /sdcard directory in the NAND memory instead of onto the actual SD card that is mounted as /mnt/sdcard.

I connected the AirPad to my Linux box and used the Linux terminal program and GNOME Commander.  The AirPad directory /sdcard showed up as a 2GB memory device and /mnt/sdcard showed up as an 8GB memory device.  So, using the two windows of GNOME Commander, it was easy to move the directories and files from /sdcard to /mnt/sdcard and I had the advantage of using the Linux keyboard and monitor.  And, I could listen to music and surf the Internet while the copies were taking place.  If it turns out that I moved some file(s) that I shouldn't have, it will be easy to find it and copy it back.

I had to reboot the AirPad to get the Storage settings values to update, but now I have 2.49GB of free NAND memory out of a total of 2.56GB.  And, App2SD moves the apps to the SD just fine, which frees up even more NAND.

Thanks to all of you for the help and I hope this will help someone.

[everydayflyer]

Tesla  thanks for the memory storage outline. This Adroid OS is beginning to make a bit more sense to me now.
My 16GB MicroSD card arrived today so now I can start moving the few games and tool apps. I have downloaded over to the SD area and still have plenty of room for some movies and such.

Is it fairly safe to say that any downloaded apps. saved (copied) over to the External SD card are safe if one must do a Factory Restore and if so how does one specify external SD and not part of the ghost(internal ) SD area?