Gp2x's Lifetime


Dr Cain posted on Feb 26 2006 at 02:57 AM said:
Since the filesystem uses write balancing, it's not really a problem since the NAND is written evenly.

Still, no writes at all is the best solution, but don't expect to be able to save your settings :p

Or you could save the settings on the SD card?
If you had one file on every card it would eliminate the need for NAND writes. :)
Although saving settings to nand is probably easier, just don't fiddle with them once you have them how you like.
 
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Dr Cain posted on Feb 26 2006 at 01:57 AM said:
Since the filesystem uses write balancing, it's not really a problem since the NAND is written evenly.

Still, no writes at all is the best solution, but don't expect to be able to save your settings :p


Well settings are only written occasionally. That should be fine. You just don't want programs using the NAND for scratch files and stuff like that.
 
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Lol. I can just see some kid at home with his gp2x on power supply, never turning it off, praying for no power outage. Writing to some geek forum in twenty years time letting them know his 2x is better than there gp50Xlturbo. :lol:
 
Shikaku posted on Feb 26 2006 at 03:00 AM said:
Technically we don't need the NAND at all...

Put the OS on the SD, it actually could be much faster this way....

i doubt that. i'm not sure what the sd transfer rate is but it's gotta be way slower than a nand memory chip that's probably copied straight into the RAM...with the sd there's probably a separate i/o chip, not to mention the speed of the card itself. i don't know though. maybe sd is faster but again i don't see how. also, with no firmware it wouldn't work out of the box.
 
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Even if exactly the same NAND blocks are constantly rewritten everytime you turn the unit on, it has an endurance of 100,000 Program/Erase Cycles. JFFS2 however has autowear leveling technology built into it however to ensure that the same block gets rewritten at little as possible, and considering that there's plenty of free space, there's plenty of alternative blocks to write to.

So, as long as you don't fill the nand full of shit, you can expect to increase to at least 1,000,000. So even with 10 nand writes per power on/off, that's still 100,000 on/off's. At an average of 6 power cycles a day, that's nearly 17,000 days or 45 years. Data retention period is 10 years.

I don't think we need to worry about the OS writing to NAND every now and again - just don't use it as an SD card.
 
Squidge posted on Feb 26 2006 at 01:13 PM said:
Even if exactly the same NAND blocks are constantly rewritten everytime you turn the unit on, it has an endurance of 100,000 Program/Erase Cycles. JFFS2 however has autowear leveling technology built into it however to ensure that the same block gets rewritten at little as possible, and considering that there's plenty of free space, there's plenty of alternative blocks to write to.

So, as long as you don't fill the nand full of shit, you can expect to increase to at least 1,000,000. So even with 10 nand writes per power on/off, that's still 100,000 on/off's. At an average of 6 power cycles a day, that's nearly 17,000 days or 45 years. Data retention period is 10 years.

I don't think we need to worry about the OS writing to NAND every now and again - just don't use it as an SD card.
haha 45 years, that really puts it all into perspective.
 
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45 years... That should be enough...
But still, I think that we dont need to write on nand. Programmers should tell if the program uses NAND or installs in there
 
Daikira posted on Feb 26 2006 at 02:16 PM said:
45 years... That should be enough...
But still, I think that we dont need to write on nand. Programmers should tell if the program uses NAND or installs in there
And thats 45 years using it every day. Not 5 years using it and then 40 years in an attic. :p
 
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But then there's the 10 year data retention issue. After 40 years in an attic all your settings would be lost. :p
 
Squidge posted on Feb 26 2006 at 12:13 PM said:
Even if exactly the same NAND blocks are constantly rewritten everytime you turn the unit on, it has an endurance of 100,000 Program/Erase Cycles. JFFS2 however has autowear leveling technology built into it however to ensure that the same block gets rewritten at little as possible, and considering that there's plenty of free space, there's plenty of alternative blocks to write to.

So, as long as you don't fill the nand full of shit, you can expect to increase to at least 1,000,000. So even with 10 nand writes per power on/off, that's still 100,000 on/off's. At an average of 6 power cycles a day, that's nearly 17,000 days or 45 years. Data retention period is 10 years.

I don't think we need to worry about the OS writing to NAND every now and again - just don't use it as an SD card.


It isn't just about write cycles though. What if the batteries go out or there is an error when writing? If the NAND gets corrupted then what?
 
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The NAND chip used in the GP2X has Program/Erase Lockout During Power Transitions (If the battery voltage is too low or unstable, the NAND is locked against writes)

If an error occurs whilst writing, the block will be marked as bad, and will then be mapped out and another used instead. The reading program will not notice the difference.
 
NAND has an electrical lifetime of 10 YEARs.

sitting on a shelf doing NOTHING.
It has to do with the capacitance of the NAND cells, it holds a charge for 0 (or 1) but that charge will slowly dissapate/ the materials will slowly degrade and become useless.

However I have heard CDRW only have a practical storage lifetime of 10 years as well.

CDR's arn't far behind them. (15 years, pedending on quality)

Odds are that GP2X will get replaced LONG before something fails.

Collectors on the other hand may have some issues with flaky flash media in the future.

(assuming it has not been replaced itself with quantum well, or millipede drive tech. or mRAM, ect)
 
rokdcasbah posted on Feb 26 2006 at 10:25 AM said:
Shikaku posted on Feb 26 2006 at 03:00 AM said:
Technically we don't need the NAND at all...

Put the OS on the SD, it actually could be much faster this way....

i doubt that. i'm not sure what the sd transfer rate is but it's gotta be way slower than a nand memory chip that's probably copied straight into the RAM...with the sd there's probably a separate i/o chip, not to mention the speed of the card itself. i don't know though. maybe sd is faster but again i don't see how. also, with no firmware it wouldn't work out of the box.

for measuring the sd-card read-speed HDPARM 4 GP2X
comes handy :)


cheers
 
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