Memory Architecture of Android

[anotherbrian]

My tablet has 32 gigabytes of memory. When I install a memory utilization app which allows me to see the amount of memory being used by each process, the application claims that my tablet has 1 gigabyte (and about 70% of it is used by pre-installed junk). I am aware that the OS is Linux and so was wondering about the way memory is being utilized.

Are the other 31 gigabytes being used as a ram disk or why doesn't the memory app report all 32 gigabytes?

Also I am curious if android mounts a remote file system.

Are linux shell commands available by android? This is were mounting a remote file system would come in handy and offer a large number of pre-existing tools.

Any recommendations of good resource monitoring apps? I found apps that display cpu usage per app and memory usage per app but none that displayed both (at least of not for free). I was looking for something like the old sysinternals programs that someone developed for windows that let you get at a lot of kernel related info.

Thanks for checking out my rookie questions.

 

[Frederuco]

There are 2 types of memory in your tablet. The Memory (1GB) is the RAM (Random Access Memory) used by the CPU to make your tablet run. The 32 GB of STORAGE is where you can keep files.

Now, on the RAM side, Android will kill off tasks as it needs RAM to run apps. Here is an article about it from a sister forum: Revisiting Android Task Killers and Why You Still Don’t Need One
Also, depending on your tablet the 1 GB of RAM may be shared between the CPU and GPU (Graphics Processing Unit) and your device may report less than 1 GB of RAM if the GPU is using some of it.

On the storage side, your tablet has a 32 GB nand flash storage card. Now, this is 32,000,000,000 bytes. Most all computers (except for the latest 2 releases of OSX) calculate disk space using 2 based math and not 10 based math. For 2 based math, 1 KByte = 1,024 Bytes (2[SUP]8[/SUP] = 1024, that is the closes we can get to 1000). So 32,000,000,000 Bytes is actually29.8 GB when your tablet does the math.

Next, you need to understand that there are different partitions on the tablet so that you can fill up the internal (/sdcard/) directory and it will still function. The 29.8 GB is partitioned into the following sections:

/boot
/system
/recovery
/data
/cache
/misc
/data/media (/sdcard/)

Each of these has some space set aside for them by the OS so that you can fill up one and the others still have room. On a Windows PC, you can fill up the C:\ drive so far that the computer will barely boot because it does not keep the OS on a separate partition.

The amount of space you see when you look at the storage part of the settings is what is in the /sdcard/ directory. The remainder of the space (typically about 2-3 GB) are split up between the boot, system, recovery, data, cache and misc partitions. So, this is why you do not see 32 GB of space.

Just be happy that you do not have a Windows Tablet, on a 32 GB tablet you have about 15 GB free after the OS is installed.

 

[anotherbrian]

Looks like android is implemented as an operating system on top of the Linux operating system- basically providing a functionally reduced java environment. It does indeed look like resource monitoring packages available for android look at the android kernel data and not Linux kernel data. So you only get the virtual view of the system that android provides and not the real view.

I can think of nothing that would prevent one from mounting a remote file system where the remote file system contained standard linux shell commands, then executing them through a java script on android. This contrasts with what I saw some folks advertise where they have one install an app which installs functionally reduced linux commands on the android. But the approach I'm suggesting would provide the entire command sets and would take a minimal amount of file space on the android box. Any comments on this approach? I suppose you have to bust the root password on the android machine.

Me being one of those folks that skipped the smartphone craze (yes I still use a Plain Old Cell Service (POCS)), I will say I find the tablet experience less than satisfying. I see those rare folks who buy expensive intel i5 based tablets running ubuntu very satisfied with their tablets. But price benefit isn't there for me - yet.

 

[jgumphress]

Google has a list of very informative videos about their system on You Tube. Develop | Android Developers