Nand Memory Question


thumpgun

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decided to defrag my nand memory through xp , when i analized (( anal -ized )) i call it , noticed it was only 29 mb in total , i thought it was supposed to have 64 mb ?. is this normal or am i thinking ram not memory....
 
Defragging flash based media like the NAND doesn't make sense and it's also a very BAD idea.

It makes little sense because flash media is accessed everywhere at once, it doesn't have a seek time like a hard disk.

It's a bad idea because defragging a drive is moving files so that they are in sequential chunks to minimise seek times... all this moving files about is doing many many writes to the flash media. As you know flash media has a limited number of writes for its lifetime. Normally it's not worth worrying about... but if you are making a habit of defragging it...
 
Regardless if it is stupid, I noticed the same thing. 30MB NAND and 30MB RAM. If the NAND is partitioned, shouldn't I see both partitions if I run fdisk? And what about the RAM? Is that separated too? Here is my df output: (I removed my SD card for clarity)

Code:
Filesystem		   1k-blocks	  Used Available Use% Mounted on
rootfs				   30704	 24804	  5900  81% /
/dev/root				30704	 24804	  5900  81% /
none					  5120		 0	  5120   0% /tmp
/dev/mtdblock/4		  32752	 13780	 18972  42% /mnt/yaffs
/dev/loop/7			  30460	  4217	 26243  14% /mnt/nand
And here is my free output:

Code:
			  total		 used		 free	   shared	  buffers
Mem:		  30884		14744		16140			0		  144
Swap:			 0			0			0
Total:		30884		14744		16140

Where is my 64 MB RAM, and 64 MB of NAND (I know the OS uses some)? I believe the yaffs and nand total the 64MB NAND, is this correct? Still doesn't explain my RAM.
 
Regardless if it is stupid, I noticed the same thing. 30MB NAND and 30MB RAM. If the NAND is partitioned, shouldn't I see both partitions if I run fdisk? And what about the RAM? Is that separated too? Here is my df output: (I removed my SD card for clarity)

Code:
Filesystem		   1k-blocks	  Used Available Use% Mounted on
rootfs				   30704	 24804	  5900  81% /
/dev/root				30704	 24804	  5900  81% /
none					  5120		 0	  5120   0% /tmp
/dev/mtdblock/4		  32752	 13780	 18972  42% /mnt/yaffs
/dev/loop/7			  30460	  4217	 26243  14% /mnt/nand
And here is my free output:

Code:
			  total		 used		 free	   shared	  buffers
Mem:		  30884		14744		16140			0		  144
Swap:			 0			0			0
Total:		30884		14744		16140

Where is my 64 MB RAM, and 64 MB of NAND (I know the OS uses some)? I believe the yaffs and nand total the 64MB NAND, is this correct? Still doesn't explain my RAM.


NAND:
It's split into several areas - bootloader, kernel, root filesystem, user storage (root and user storage are viewable in the df output above). It's not partitioned the same way as hard drives, so running fdisk on it doesn't make sense. You can view the 'partitioning' by catting (I think) /proc/mtdinfo or something else starting with mtd, I forget.

RAM:
32 MB is managed by linux - this is all linux "sees" - the upper 32MB is empty or used by misc. things, such as video framebuffer, sound buffer, code/data for video decoding (done partially in hardware and assisted by the 940). Hardware accelerated SDL also uses the upper 32MB for textures.
 
Last edited by a moderator:
Regardless if it is stupid, I noticed the same thing. 30MB NAND and 30MB RAM. If the NAND is partitioned, shouldn't I see both partitions if I run fdisk? And what about the RAM? Is that separated too? Here is my df output: (I removed my SD card for clarity)

Code:
Filesystem		   1k-blocks	  Used Available Use% Mounted on
rootfs				   30704	 24804	  5900  81% /
/dev/root				30704	 24804	  5900  81% /
none					  5120		 0	  5120   0% /tmp
/dev/mtdblock/4		  32752	 13780	 18972  42% /mnt/yaffs
/dev/loop/7			  30460	  4217	 26243  14% /mnt/nand
And here is my free output:

Code:
			  total		 used		 free	   shared	  buffers
Mem:		  30884		14744		16140			0		  144
Swap:			 0			0			0
Total:		30884		14744		16140

Where is my 64 MB RAM, and 64 MB of NAND (I know the OS uses some)? I believe the yaffs and nand total the 64MB NAND, is this correct? Still doesn't explain my RAM.


NAND:
It's split into several areas - bootloader, kernel, root filesystem, user storage (root and user storage are viewable in the df output above). It's not partitioned the same way as hard drives, so running fdisk on it doesn't make sense. You can view the 'partitioning' by catting (I think) /proc/mtdinfo or something else starting with mtd, I forget.

RAM:
32 MB is managed by linux - this is all linux "sees" - the upper 32MB is empty or used by misc. things, such as video framebuffer, sound buffer, code/data for video decoding (done partially in hardware and assisted by the 940). Hardware accelerated SDL also uses the upper 32MB for textures.
thanks for the info ,learning is good :D
 
Last edited by a moderator:
/dev/mtdblock/4 32752 13780 18972 42% /mnt/yaffs
/dev/loop/7 30460 4217 26243 14% /mnt/nand
this are two of the nand partition /mnt/nand is what you see when you select the nand option in the filebrowser, /mnt/yaffs is where the system is.
Additional to these there's a very small 3rd partition in which the bootloader is.
 
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