flash memory life

Discussion in 'iPhone' started by iCheese, Oct 21, 2007.

  1. iCheese macrumors regular

    Joined:
    May 31, 2006
    #1
    Flash memory is supposed to have a limited life from what I have read. How long will it take for the memory in an iPhone to die from constant syncing?

    I am sure the memory would last longer than the amount of time it would take the average person to upgrade to a new phone, but it would be interesting to actually know around how many years the memory would last.
     
  2. shrewsburywolf macrumors regular

    shrewsburywolf

    Joined:
    Sep 21, 2007
    #2
    "flash memory has a finite number of erase-write cycles (most commercially available flash products are guaranteed to withstand 100,000 write-erase-cycles for block 0, and no guarantees for other block"

    "some industry analysts[1] have calculated that flash memory can be written to at full speed continuously for 51 years before exceeding its write endurance"

    http://en.wikipedia.org/wiki/Flash_memory#Limitations
     
  3. iCheese thread starter macrumors regular

    Joined:
    May 31, 2006
    #3
    Thanks for the informative reply. Guess there really isn't anything to worry about :D
     
  4. shrewsburywolf macrumors regular

    shrewsburywolf

    Joined:
    Sep 21, 2007
    #4
    No worries, I think the only thing you will have to worry about is decreasing battery life, but you will have probably replaced it by then anyway!
     
  5. kdarling macrumors demi-god

    kdarling

    Joined:
    Jun 9, 2007
    Location:
    First university coding class = 46 years ago
    #5
    The Flash memory used in the iPhone has a relatively limited endurance of "only" 5,000 program/erase cycles.

    Even with a limit of 5,000 cycles, that's still a rewrite of a single memory section each day for over 13 years. And in real life, OS algorithms avoid rewriting the same locations. Plus it has spare memory cells to use if/when the main memory sections fail.

    So it should last a pretty long time in real operation. But that's why it's not used to store web cache, etc... just rarely changing stuff like media and programs.
     
  6. marcol macrumors regular

    Joined:
    Jun 6, 2005
    Location:
    Norwich, UK
    #6
    I haven't seen much on memory architecture (is that the right term?) of the iPhone. I'd be grateful for a pointer in the right direction. Something like this (which relates to Windows Mobile devices) would be great:

    http://blogs.msdn.com/windowsmobile/archive/2005/08/19/453784.aspx
     
  7. marcol macrumors regular

    Joined:
    Jun 6, 2005
    Location:
    Norwich, UK
    #7
    At the risk of (at least partially) answering my own question I did find this very helpful electronicsweekly.com article:

    http://www.electronicsweekly.com/Articles/2007/09/05/42117/inside+apples+iphone.htm

    Summary of what it has to say about memory:

    NAND. 8 or 4 Gbyte. Stores most of the operating system code, music and video files, and other non-volatile stored data.

    NOR. System boot code is stored in NOR. There are two NOR chips, one feeding the main ARM CPU and one (4 Mbyte) feeding the Infineon GSM/EDGE RF chip.

    Mobile DDR SDRAM (or possibly SRAM). Present as a 'two-package stack'. Amount unspecified. Volatile memory [used for manipulating applications and data].

    16-kbyte/16-kbyte code/data cache on the ARM processor.
     
  8. kdarling macrumors demi-god

    kdarling

    Joined:
    Jun 9, 2007
    Location:
    First university coding class = 46 years ago
    #8
    IIRC, a check on free memory shows 111MB of RAM. So they figure 128MB, but 17MB used by the OS and/or shared elsewhere.
     
  9. marcol macrumors regular

    Joined:
    Jun 6, 2005
    Location:
    Norwich, UK
    #9
  10. scaredpoet macrumors 604

    scaredpoet

    Joined:
    Apr 6, 2007
    #10
    Also keep in mind that unless you're frequently changing up the music that's going into your iPhone, there's not going to be a lot of re-write activity going on with every little sync. Only information that changed since the last sync is re-written.
     

Share This Page