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Overhead on memory sticks?

Discussion in 'Electronic Design' started by Joerg, Apr 5, 2007.

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  1. Joerg

    Joerg Guest

    Just curious: Got a USB memory stick 4-pack at CostCo. Four Dane-Elec
    512MB stick, great deal ($40). After plugging in the first one the
    laptop hard drive was crunching a lot (this laptop is used to USB
    sticks). Upon checking an empty stick it turns out that properties lists
    514MB but only 490MB of that free.

    What kind of overhead is in those sticks? If it's really >20MB, why so much?

  2. Maybe because 514/(1.024*1.024) = 490.2?
  3. Ben Jackson

    Ben Jackson Guest

  4. Joerg

    Joerg Guest

    That I understand. But it still doesn't explain why an empty stick has
    so much overhead. As a comparison, my oldest memory stick has a much
    lower overhead percentage. It's a 1GB Lexar and the overhead is only
    14MB, versus 24MB on the new 512MB sticks. Looks like the new ones are
    more than a factor of three higher in overhead.
  5. Joerg

    Joerg Guest

    But 2^19 = 524.29 :)

    Anyhow, whatever number of cells they squeezed in, if the net available
    space is 490MB it shouldn't be advertised as 512MB. But I am not
    complaining, it's enough for my purposes. Just wondering.
  6. JeffM

    JeffM Guest

  7. There's the marketing megabyte, which is 10^6 = 1000000
    Then there's the 'proper' megabyte: 2^20 = 1048576

    Not incidentally, 514*10^6 = 490.2*2^20.

    It's not filesystem overhead. It's a matter of perspective.

  8. It is a rotten deal, a 2GB stick goes for 14,95 Euro (19.99 $ as today).
    Here is where I buy stuff and DVDs etc:
  9. Phil Hobbs

    Phil Hobbs Guest

    The same is true of disk drives--the free space reported is that
    actually available for files, and excludes e.g. file system data
    structures and hot spare sectors. I don't know what Windows reports in
    Properties, though--I've given up trying to guess.


    Phil Hobbs
  10. Joerg

    Joerg Guest

    Yeah, I know you can get really large sticks in singles. But these came
    in really nice designs and dazzling metallic colors :)

    I don't need 2GB and for $20 I'd only get one physical device. What I
    need them for is when I go to clients. Blue is for client A, silver is
    for client B etc. My old rule is to never, ever, mix that together. My
    wife liked these so much she wanted to have the red one. Not that she
    needs it but because it's pretty. Have to think about that...
  11. Jim Yanik

    Jim Yanik Guest

    I just bought a 512MB "Attache" USB memory stick from CompUSA for
    17.00,with a 13.00 rebate,so end cost was $5.(plus tax on $17,of course)
    I hate rebates,though;PITA.

    Too bad CompUSA's site said the stick was usable on "W98/SE",and other
    similar sticks said "SE-only",so I thought it would work with my W98 1st
    edition system;nope. No drivers for W98FE.
  12. Joerg

    Joerg Guest

    I don't like mail-in rebates at all. IMHO it's a stupid concept and I
    generally do not buy if that's the form of rebate. But I guess they bank
    on the hopes that some people will "forget". Plus maybe all the tourist
    shoppers and not-so-legal aliens who don't have a US bank account and
    cannot cash in those rebates.

    Then I guess you'd be entitled to give it back.
  13. Rich Webb

    Rich Webb Guest

    [Apologies for continuing off topic but] I've discovered that CompUSA,
    on at least some rebates, handles all of the processing on-line. Go to
    the magic web site and enter your store ID and receipt number; the
    rest is pretty much automatic. They still take forever to arrive in
    the mail, of course.
  14. Jim Thompson

    Jim Thompson Guest

    All the CompUSA stores around here are closing up shop. Even
    resorting to the auto lot game of hiring a kid to stand on the corner
    and wave a "going out of business" sign.

    ...Jim Thompson
  15. Tim Shoppa

    Tim Shoppa Guest

    1GB is really 1024MB, right?

    1024-986 = 38MB.

    So it has more overhead than the 512MB stick.

    I remember when I was proud of shaving off a word (two whole bytes!)
    from a PDP-11 subroutine!

  16. Jim Thompson

    Jim Thompson Guest

    On Thu, 05 Apr 2007 12:57:48 -0500, Spehro Pefhany


    I have an OfficeMax account... they deliver for free. I have all
    kinds of coupons, $30 off in the store and 20% off from the web, etc.

    I usually end up with really good prices from them.

    ...Jim Thompson
  17. Joerg

    Joerg Guest

    Not this one. Was marketed as 1G and shows 989 usable. I go by what the
    marketeers have promised and what the product actually delivers ;-)

    My father had to do that. Automated a complete cold-rolled-steel line
    within 2K of RAM. Which was a lot back in the 60's. Just imagine, in
    Vista they recommend to provide 1G (!) just to make sure it can work at
    all. Lots of bloat, needs half a million times what my father and the
    guys needed. Pathetic.
  18. Disk drive megabytes (10^^6) have always been smaller than memory
    megabytes (2^^20).

    I guess the question then becomes: is a flash stick a disk drive or a
  19. Joerg

    Joerg Guest

    More like a drive because the PC handles it as such.
  20. OfficeMax and Best Buy (starting with their Canadian stores) are
    finally getting rid of the d*mn things.
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