Quote:
Originally Posted by m4f1050
Ok, since I had this doubt I figured I'd start a new thread to keep other thread clean.
What I understand so far:
1. NAND (internal memory) is used as "hard drive" and to store OS (what about installed apps?)
2. SDCARD (external memory) is used as "external hard drive" same as internal memory
3. RAM (where OS and APPs load into)
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All correct.
Quote:
Originally Posted by m4f1050
Here are a few doubts I have....
When you boot your phone the OS gets loaded into RAM from the (in our case) SDCARD and when you turn it off this memory gets wiped out because it's volatile?
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Not quite "wiped". The android system is loaded into RAM, but the file system remains active (just like WinMo) so you can install programs and adjust settings. These are all saved to the data.img file on the SD card.
Quote:
Originally Posted by m4f1050
Is the NAND and RAM shared in some way? Is it partitioned in any way? I remember back in the WM2003 days you could slide and pick where your memory would be used at, but that changed a long time ago. I am guessing that got replaced by RAM/NAND combination?
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Not really. Think of it like a computer. When the PC boots some of its memory is used by the operating system (stored on the hard drive, or in NAND for the phone) gets loaded into memory so it can be run.
Quote:
Originally Posted by m4f1050
On HTC website if you check phone specs it gives you 2 different memory sizes (I believe one is RAM the other is ROM) is NAND = ROM?
Is it called ROM but we can "write" to it? It's just a name for it that stores the OS ROM (or should I call it OS installation?) I'm sure there are a few of us that are confused because ROM IS READ ONLY MEMORY written once, never to be written again and again like a "hard drive"...
Examples:
TP2: ROM: 512 MB / RAM: 288 MB
Imagio: 512MB / 288MB (256MB Device + 32MB MSM), SD Card supported
HD2: ROM 1GB; RAM 576MB
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"ROM" is a bit of an incorrect term, and not at all like a hard drive (which is definitely not write once). Part of the NAND is treated like "ROM", but other parts are read/write just like RAM. The difference is that anything stored in RAM goes away after power cycle or soft reset.
Further confusing the issue is that even the portions that are normally "ROM"-like are actually re-writable for things like firmware updates.