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On a PC, there are hard disks acting as storage space where the operating system and application files are stored, and there is RAM which is memory which gets used up by the operating system executable code and applications executable code while everything is running.

On my Samsung Galaxy SIII, when I go to Settings -> More -> Storage, there are various sections which talk about storage space and memory as though these were the same thing?

So here come my questions:

  1. Apart from storage space provided by the optional SD card which must be inserted into the back of the phone next to the SIM card, is there a single memory chip acting as both a storage medium for files when the device is turned off as well as random access memory for the running operating system executables and apps in execution? As the following screenshot reports there seem to be 16.00GB on my device used both as a hard disk and as RAM. Is this how this storage medium works, a single chip for both?

  2. Where can I see the amount of space available on my SIM card? According to Wikipedia such space can only be used to store specific kinds of data such as network-specific information, a maximum of 250 contacts (except for newer models) where each contact can only consist of a name and single phone number pair, and SMS messages. SIM card capacities are also limited to 32KB to 128KB or more, but in any case it's a very small amount of space. It could be that because of these limitations the Samsung Galaxy SIII and other modern Android phones do not make use of this space for user data, but correct me if I'm wrong.

Thank you for your replies.

Storage/Memory on the Samsung Galaxy SIII

  • Thank you for your suggestion. The reason I touched upon the topics of internal storage, external SD card storage, SIM card storage, and temporary RAM memory storage in one post is that I was simply looking for one thing: the big picture concerning how memory and storage is broken down on Android phones and where on the system these parameters can be accessed, hence a single post. I have received answers on this topic. If after this explanation you still think I can reword my post better, then please let me know and I will act accordingly. Thanks. – John Sonderson Dec 4 '14 at 17:30
  • Thanks. The reason I didn't accept yet is just one thing. I was just waiting to see if the term device memory refers consistently to internal memory which is not system memory, or whether in some contexts the term device memory can also be used to refer to all device memory. If you know the answer please post a comment and I will accept the answer given below. Thanks. – John Sonderson Dec 4 '14 at 20:16
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    No 100% proof or able to cite a source, but I've never seen "device memory" referring to RAM. And with one thing I am 100% sure: It never refers to /system (where the OS stuff resides). Keep in mind we have no control how "laymen" might use the terms in forums etc :) – Izzy Dec 4 '14 at 20:41
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In this respect, there is no difference between regular PC and Android.

The terminologies, however, is slightly confusing.

System memory refers to the storage space that is used by system files, and Device memory refers to all storage space. Device memory does not refer to RAM. Your device's RAM can be seen in Settings -> More -> Application Manager.

is there a single memory chip acting as both a storage medium for files when the device is turned off as well as random access memory for the running operating system executables and apps in execution?

Sort of. Most Android device uses a System-on-chip (SOC). What is included in a SOC varies depending on the particular chip and device, but a typical SOC may have CPU, RAM, GPU, wireless, and possibly storage manufactured in a single chip. In regular PC, these are usually separate components, SOC is used in mobile devices to save space wasted due to separate component packaging, but internally there is still a delineation between the components.

Where can I see the amount of space available on my SIM card?

AFAIK, you can't. Android have very limited support for SIM card facility. It uses the SIM card only for Telephony functions and importing existing contacts there into the device's address book.

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    It's worth adding that usually in the Android GUI, "memory" means non-volatile storage, and "RAM" means RAM. It's a bit confusing because that's not usually what people call the two things, but that's how it is. – Dan Hulme Dec 4 '14 at 15:48
  • I've downloaded several applications under the names of SIM, SIM Card, SIM Card Info, SIM Card Information, SIM Card Manager, and so on, but almost all of them seemed to report almost no information stored in the SIM card, no contacts, just a SIM card device ID (IMEI/MEID/ESN) and a little bit of other garbage, but no data pertaining to amount of space available on the SIM card. Thanks. – John Sonderson Dec 4 '14 at 18:32
  • @LieRyan, would you be able to clarify your answer as far as the "device memory" bit is concerned? When I go to "Settings -> More -> Application manager" as you say, it reports roughly 8GB used and roughly 3GB free, out of a total of 16GB of internal storage memory. When I go to "Settings -> More -> Storage" the "System memory" storage reports roughly 5GB. Since 8GB + 3GB + 5B = 16GB, this seems to indicate that the term "device memory" refers to all memory which is not system memory. That is: total internal memory = system memory + device memory. Can you please confirm? Thanks. – John Sonderson Dec 4 '14 at 18:44
  • On the "Settings -> More -> Storage" screen a similar breakup is also present, since on that screen "Used space" is userland internal storage memory space which excludes "System memory" internal storage memory space. Thanks. – John Sonderson Dec 4 '14 at 18:49
  • @JohnSonderson: Sorry for not being too clear, to see the RAM, go to Settings -> More -> Application Manager and go to the Running tab. That is the one that shows your RAM. – Lie Ryan Dec 4 '14 at 21:45
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Now I realize that as to the first part of the question, as pointed out, the Storage screen is displaying information on internal storage (excluding SIM card storage space, external SD card storage space, and RAM memory which is just a temporary storage location which is on a separate chip and does not serve as a persistent storage location).

The reason I was getting confused is that the terms storage and memory are mixed interchangeably on this screen. Even more confusing, on the Samsung Galaxy SIII site the amount of this internal storage is listed under the heading Memory with subheading Total Internal Memory: 32 GB / 16 GB Internal Memory, whereas in the world of desktop computers the term memory usually refers to RAM. This is what was confusing me.

I later realized that to view the amount of RAM (including the percentage of unavailable RAM on the system) there is another window which can be accessed by long-pressing the Home hardware key and then clicking on the pie-chart icon in the lower-left hand corner, as in the following screenshots:

Running Processes: Pie-Chart Button Shows Total/Used RAM Total/Used RAM

I've added a picture of what a SOC (System-on-a-Chip) looks like. As posted, many systems now come as SOCs with CPU, internal memory, RAM, and other component all integrated into one chip but at the same time still separate from one another.

SOC: System-on-a-Chip

As an alternative place where to find information on RAM used as opposed to long-pressing the Home key and clicking on the pie-chart icon, one can also go to Settings -> More -> Application manager and swipe twice to the right to see the RUNNING tab which displays the same information at the bottom as in the following screenshot (click to enlarge):

enter image description here

The above screen displays all running processes. By contrast, long-pressing the Home hardware key only displays those running processes which have a GUI in the foreground, excluding background tasks.

Thanks.

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