If flash memory doesnt last very long - how long will my n900?
 

I keep hearing that flash memory doesnt last very long, and that you can only overwrite it a set number of times - so how long will my n900 last? I know it has plenty of space (around 25gb free as brand new on mine with only default apps installed) but if I installed/uninstalled programs every day could I expect the phone to last much more than a couple of yrs? Or does the memory it uses differ much from what most phones used, say, 5 yrs ago, in terms of lastability? thanks

Re: If flash memory doesnt last very long - how long will my n900?
 

Flash memory lifespans have been increasing in leaps and bounds ever since flash memory was first developed, while flash memory does still have a lifespan you can be reasonably safe in the knowledge that the life expectancy of the flash chip in your N900 is longer than yours.

Re: If flash memory doesnt last very long - how long will my n900?
 

This has been discussed in previous posts...

dont worry about the memory. i think someone did some maths and worst case would be 5yrs with extreme use and i mean extreme

just remember that all fails are worked on MTBF so it is not an exact science

Re: If flash memory doesnt last very long - how long will my n900?
 

lol, thanks. haha-my last phone was a sony cybershot k800, it lasted a fair while (almost 4 yrs), it still works but Im certain the memory it uses is starting to go/just about completely gone. It can take a long time to start up, and even trailing through the menus to play, say, an mp3, can take aeons... !!! thats why ive replaced it with this n900 (not out of choice, was a present-a hint from a member of the family that I really needed to be up to date, haha). Im just hoping it will last a fair while in comparison

Re: If flash memory doesnt last very long - how long will my n900?
 

I have used SD cards since 2004 and none of those have failed me yet. To wear one out I think that in practice you would have to write extensively to the card every day, and keep the card quite full. With 'normal' use, and if you don't fill up the card to the maximum (that would decrease the efficience of the wear-leveling algorithm) then the card should last so long you'll feel it's obsolete before it wears out.

Re: If flash memory doesnt last very long - how long will my n900?
 

doesnt reading from flash memory age it as much as any writing? i always thought it did

Re: If flash memory doesnt last very long - how long will my n900?
 

extent: No, reading doesn't wear it out the way writing does.
Whenever a file is updated the card will write the new content back to another set of blocks, not the original ones. Each block has a limited number of writes before it wears out, so by moving data around that like it distributes the writes around the card. Reading by itself doesn't wear out the card the same way.

EDIT: The 'short article' about flash on wikipedia (there are longe ones too), says "The main weakness of flash memory is the number of times that data can be written to it. Data can be read from flash as many times as desired, but after a certain number of "write" operations, it will stop working. Most flash devices are designed for about 100,000 - 1,000,000 write operations (or "write cycles")."

Re: If flash memory doesnt last very long - how long will my n900?
 

Ill prob try not to delete/write too often, once its got all my contacts, some useful apps (games-ahem), and mp3s, ill be pretty happy. no doubt most of the writing/reading will be with changing music lists, but theres no chance id be able to fill the mobile up with 20+gb's worth...

if old blocks for data fail, and the phone can detect them and write to a different block instead (would i need to install an app for making sure bad blocks are never written to again?) then the phone should last a fair while, especially when theres this much space available... thanks

Re: If flash memory doesnt last very long - how long will my n900?
 

Can one redirect all the 'temporary' stuff to the external card to reduce the impact? I do not know how, but just want to ask the question.

Re: If flash memory doesnt last very long - how long will my n900?
 

@extent and cheve: Interesting question but this is not an issue you should worry about.

@TA-t3 - Don't be so sure that the device does this. My Olympus camera (1 yr old) always fills 'from the bottom up' and over writes old blocks as soon as they are free. I'd expect the N900 not to do this as it's should really be more intelligent, but I'm sure.

Re: If flash memory doesnt last very long - how long will my n900?
 

what about the rootfs? That's being read and written all the time. And the swap? A different partition doesn't mean specific blocks? SD cards that hold photos never go near the number of writes an OS does when its running.
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Re: If flash memory doesnt last very long - how long will my n900?
 

Wear-leveling on SD cards isn't handled by the device, it's a built-in feature of SD (and MMC) cards.

Re: If flash memory doesnt last very long - how long will my n900?
 

Is that SD? Sure it isn't XD? In any case, how would you know if the blocks are overwritten (not moved), it's not something that's visible on the operating system layer. And finally, the SD specification includes built-in wear leveling.

http://en.wikipedia.org/wiki/Flash_memory#Memory_wear

Re: If flash memory doesnt last very long - how long will my n900?
 

That's the built-in flash, not an SD card. Different rules apply. The eMMC is a different story again.

Re: If flash memory doesnt last very long - how long will my n900?
 

@TA-t3 - It's SD and I'm sure of the behaviour as I've performed data recovery on the space and tested it.

You've misquoted Wikipedia there as well (outrageous behavior)
anyway, this is moot until someone tests the N900.

Re: If flash memory doesnt last very long - how long will my n900?
 

That's RAM. A reading from RAM refreshes the info (the state of each cell) just like a write.

Re: If flash memory doesnt last very long - how long will my n900?
 

yeah, i just thought it might have been the same with flash, I guess not! :) thanks

Re: If flash memory doesnt last very long - how long will my n900?
 

i wouldnt worry, im using a 64MB CompactFlash card i got in 2001 to transport files from OSX to Windows in bootcamp (using a card reader) and its never let me down.....so far(?)

Re: If flash memory doesnt last very long - how long will my n900?
 

What you mean is D(ynamic)-RAM since flash is also a type of Random Access Memory. The N900 has only RAM type memory.
I also suspect that the root partition might be a different flash technology with smaller memory blocks or longer lifecycle.

Re: If flash memory doesnt last very long - how long will my n900?
 

The rootfs is managed by UBIFS, which does wear levelling across the entire 256MB.

Not as much as you might think. Most of the files on the rootfs are extremely static.

Re: If flash memory doesnt last very long - how long will my n900?
 

This is getting silly! Stop being so paranoid and enjoy your phone people.

The number of moaning threads around here worrying about the n900 is crazy! it seems as if there's a pessimist attack

Re: If flash memory doesnt last very long - how long will my n900?
 

Wait until the PR1.2 is out and everyone is starting to cry that they didn't get everything they expected... things like "WHAT? No MMS?"

Re: If flash memory doesnt last very long - how long will my n900?
 

The longs start time has nothing with flash memory wear - if flash has a read error it has it and phone can't start or it could start without some functions or files. It is not CD which tries to re-read with long mechanical movement.

I can't say for sure for unknown phone model but I suspect the reason is in the LARGE memory sizes since you started with this phone. Phone software may have a difficulty to handle a long list of files in your today's big SD card.

Re: If flash memory doesnt last very long - how long will my n900?
 

Not a full truth. Flash random read actually sometime updates memory NOW. Moreover, a modern flash chips require a periodic connection to power because it auto-refreshes the written data. It means that just keeping SD in memory slot of any device is much safer for data. But please take in mind that degradation period can be actually measured in years without power and don't worry about it until you try to put your data in mountain bank vault.

Repeated reads of the same block in short time doesn't produce any wear effect in many chips - it reads it from some chip cache. The same is for sequential data read because chip actually reads BIG block and responds the computer with small requested amount and continues from that buffer.

However, writes does a little more degradation to chip structures but that is greatly decreased with latest chip generation. Of course, the brand name has toll but I am sure Nokia did a good job here.

Re: If flash memory doesnt last very long - how long will my n900?
 

still flash memory though...
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Vaporizer review

Re: If flash memory doesnt last very long - how long will my n900?
 

I most CERTAINLY did not! How dare you.
What you quoted above is about flash memory _in general_.
Just read on from there and downwards. Until you get to NAND, and SD in particular.

Re: If flash memory doesnt last very long - how long will my n900?
 

I used to have a Canon Powershot S40 with a small CF card that eventually had a few "sectors" go bad. But it was a first gen flash card, in an early camera, that got a lot of heavy use. Chkdisk'ing the card mapped out the bad part and I could continue using it, although it would only hold about 70 images instead of the 100 or so prior to the failure. Had I kept using the card in the camera I'm sure the degradation would have continued. The only way I noticed it was the reduced capacity. In fact I don't recall loosing any data, just that Windows didn't want to read it until I did a chkdisk on it.