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CompactFlash memory card

Discussion in 'Help Team' started by RogerChristie, Sep 2, 2010.

  1. Scphoto

    Scphoto Well-Known Member

    I've worked in IT all my life so had this discussion many times before. Probably why I'm so dismissive of this lie.
     
  2. P_Stoddart

    P_Stoddart Well-Known Member

    First you have to understand that CF memory card are not just used for digital cameras or solid state hard drives. They are also used as boot roms for hard application bespoke technology. Therefore any electronic engineer when told this is 32GB of CF is going to expect 34359738368 bytes of available space for code. Also the same chips (or chip design) are used in other technology.

    I presum all of your figures are coming from your computer or digital camera?

    Therefore there is alot of third party technology talking to your CF card. The OS, the reader, the device driver for the reader etc. So it opens up the avenues of a software bug or even a hardware one. Some reading devices are not compatible with 32GB. When you run a scandisk or error check does it report any bad sectors? That would certainly cause a loss of capacity.

    I know from experience at the hard end of computer engineering that blaming the new device can be easy but wrong. Many a times it is a flaw in a old device or driver that has decide to appear now.

    There is a program called h2testw that is designed for memory card. It was wrote because of dodge memory card that DID lie about there size ie 2GB only being 1GB. But it might take along time to run as it does a very detailed test.
     
  3. pachinkofan

    pachinkofan Well-Known Member

    I remember wondering if I had a problem with my first ever sd card when it didn't show up on my PALM Tungsten organiser as the full size I was expecting but realised when I checked the card's website that some of it was used for "workings" of the card so to speak, and the Kingston site specifies this on the standard cf cards' page too:

    #* Please note: Some of the listed capacity is used for formatting and other functions and thus is not available for data storage.#

    Then again, the PALM also adds a couple of folders and files onto the card for its own workings, but overall I don't consider it as a lie. Just as something that needs to be there to allow me to use the card, and while the first time I "bawlked" at the size of the used space, it certainly makes little difference to what I can put on it.
     
  4. Roy5051

    Roy5051 Well-Known Member

    Sorry,I disagree. 1000MB is correct in mathematical terms, but in computing terms, where everything is to the power of 2, the correct figure is 1024 - I am afraid we may have to differ on this one.

    Your previous post explains the reason why the industry uses this discrepancy, so as I said, we just have to accept it. 32GB is 32,000,000,000 bytes (in industry terms), but will show up on computers (including cameras which are mini-computers) as 30.5GB, because computers expect the use of 1024 not 1000.
     
  5. spinno

    spinno Well-Known Member

    Am I the only one who sees this as an Atlantic depression in a bone china drinking vessel
     
  6. Fen

    Fen Well-Known Member

    I think that makes 00000010 of us :D :D
     
  7. Benchista

    Benchista Which Tyler

    No, Roy, by definition you are wrong - disagree as much as you like, but the body that defines the meaning of the prefixes is adamant that you're wrong, and that the correct definition is nothing to do with the power of 2 - that's where the "i" comes in. The problem is we've all got used to thinking erroneously of a gigabyte as 1024x1024x1024 bytes, whereas that's actually 1GiB, NOT 1GB. The memory industry are correct, the rest of the computer industry, using binary definitions, is wrong. Sorry, but there's no point perpetuating misconceptions.
     
  8. Roy5051

    Roy5051 Well-Known Member

    I bow to your greater knowledge of the inclusion of the letter i in deciding the value of Gigabytes, etc, but until mentioned in the thread, I have never heard of this letter being included in any description of computer memory.

    Surely the point is that these descriptions should be transparent to the people who are buying these goods (i.e. the customers).

    So, to make these descriptions clear in the future, vendors should make clear what the size of their memory chips are. If the correct description of a GB is 1,000,000,000 bytes, this should be stated on all advertising, by the manufacturers and the vendors, and explained that, when used in a binary computer, it may appear to be less than the customer may be expecting.
     
  9. Benchista

    Benchista Which Tyler

    Can't argue with that, it would be very helpful.
     
  10. P_Stoddart

    P_Stoddart Well-Known Member

    I too agree. In fact the manufacturers could just put the byte count in small print on the packaging.

    I just checked on my XP system. One of my HD has

    11,261,280,256 bytes free space which it also reports as 10.4GB the only way for it to arrive at that figure is to divide it by 1024^3 or 1073741824. It has been like that since computers became mainstream in the 1980s. Never heard of GiB until this thread.

    But that is not the issue. I know for experience so system cannot cope with storage at 32GB hardware designers keeping cost down. I have memory card reader that will not read any SD above 1GB correctly. Sees it but does not read data correct in the second 1GB. Does format it.

    Could it be your hardware is restricting the 32GB down to account for some limitation in the device handling. I had another look at the whole thread I cannot see what hardware you plug this 32GB into? The OS can only work with the hardware it runs on. The whole 32GB and 32GiB is a side issues IMHO. It is the actual bytes count that nail if there is a shortfall. Like you say there is a aweful lot of bytes gone missing. If you take the overhead of your 16GB which will have a raw size of 17179869184 bytes it uses 1162149888 to format the card.

    Therefore you have a card that is double the size. So if the format uses double we end up with 2324299776. Card has basic 34359738368 bytes of raw space. Therefore should at least end up with 32035438592 maybe a bit less but not what you get. Could be the hardware reading the card. Have you asked the manufacture the precise byte count of the 32GB card and what they would expect to see under FAT32 after format?

    So I now see where you are coming from. If it was 32,000,000,000 bytes you would end up with even less at 29,675,700,224.

    One final issues your 8GB cards. I cannot understand why the bytes count are varying? Same hardware, same format. Why different free space? Again there is low-level format free software on the net for wipe drive. There is even free security wipe software to protect your data. Again the security software does take awhile to wipe but it does test out the memory card.
     
  11. RogerChristie

    RogerChristie Well-Known Member

    Let me try and explain one last time. For those who are still confused this is as simple as I can make it (sorry to those who may feel patronised)

    Decimal goes:
    10×10×10 = 10^3 = 1,000 = 1K (Kilo-),
    10×10×10×10×10×10 = 10^6 = 1,000×1,000 = 1,000,000 = 1M (Mega-),
    and so on.

    Binary goes:
    2×2×2×2×2×2×2×2×2×2 = 2^10 = 1,024,
    2×2×2×2×2×2×2×2×2×2×2×2×2×2×2×2×2×2×2×2 = 2^20 = 1,024×1024 = 1,048,576,
    and so on.
    Now you can’t call that Kilo-, Mega- etc as well ‘cos it isn’t.
    Unfortunately, a long time ago, some idiot in IBM (or somesuch company) did, and that’s where the confusion started. *

    I’m supposing you are using Windows. Open Windows Explorer. Click on the little + sign beside My Computer. Right click on your hard drive (typically Local Disk (C:), but it works for any drive). Click Properties. Click on the General tab (if it isn’t already showing). Just above the pie chart mine says Capacity: 39,999,500,288 bytes, (which is 39.999500288 Gigabytes).
    A little further to the right it says 37.2GB. The 37.2GB is WRONG. Just ignore it.

    -----------------------------------------------------------------------------
    * The International Electrotechnical Commission proposed the prefixes Kibi-, Mebi-, Gibi- etc back in 1999. Eleven years later it still isn’t in general use. The Bureau International des Poids et Mesures (who maintain the SI system of units) still haven’t adopted it. For goodness sake, the USA still haven’t adopted the SI system and that has been on the go for the last 50 years! (The USA is now one of only three countries in the world that don’t officially use SI. The other two are Burma and Liberia.)
    (I can only suppose that there is a bunch of incompetent bureaucrats somewhere sitting on their fat butts, talking nonsense, drinking tea, and creaming in bloated expenses out of our taxes. I don’t want to frighten AP’s lawyers, but I do hope they sue me for libel. It might be the only way I’ll find out just what they have been doing all this time. I’m not holding my breath though.)
    -----------------------------------------------------------------------------
    For more detail on binary multiples http://en.wikipedia.org/wiki/Gibibyte would be a good place to start.
     
  12. RogerChristie

    RogerChristie Well-Known Member

    As for the rest of the comments:

    First, thanks for your support Nick.

    I ran “scandisc” and also “repair bad sectors”, P_Stoddart. It increased the capacity from 30,513,397,760 to 30,515,249,152 bytes. I checked the capacity on two separate computers. The numbers were the same.

    The comments about memory reserved for the control system are actually a red herring. The figures I quoted are TOTALS.

    _____________________________________________________
    P_Stoddart: I cannot understand why the bytes count are varying?

    The memory on Flash cards is split into blocks (just like the memory on magnetic drives is split into sectors). I don’t know the exact figure, but suffice it to say that each card has millions of blocks. The cards have a built-in circuit such that if a few blocks fail they are simply isolated. In fact cards don’t last forever, and blocks will continue to fail occasionally. They too are isolated and your memory card should still remain perfectly usable for years.
    Even straight off the production line it is likely that a card will have a few duff components. A perfect 32GB card would have a little over 32GB (I see you quote 32×(2^30), ie around 34.4 GB). Whatever, this excess means there is some leeway to allow for failures and the final product should still show a little over 32GB total when new (just as my 16 and 8 GB cards show a little excess over the nominal capacity).

    _____________________________________________________

    All this stuff is actually superfluous to my complaint however. My 32GB card was almost 5% under and I don’t consider this is acceptable. Nevertheless, if (as I initially expected) the supplier had simply accepted that the item was faulty and promptly replaced it I wouldn’t have made a fuss.

    What actually happened was that they tried to con me into accepting that such short measure was normal. And, much to my surprise, Trading Standards agreed with them.

    If your IT department bought and paid for 100 new computers and only 95 were delivered they’d be fuming, and justifiably so. I don’t see the difference.

    I’m actually at a loss to see why the logic of the situation seems to escape the manufacturers, the suppliers and the consumer protection agency that (to state the bleedin’ obvious) is supposed to be protecting the consumer. I’d be happy for someone to prove otherwise, but I can only suppose that they are all either idiots or scoundrels. Either way, I won’t be taken for a fool, so, no Fen, computers, gigabytes, small potatoes or large ones, it isn’t by any means a storm in a teacup.
     
  13. RogerChristie

    RogerChristie Well-Known Member

    Sorry Fen, it was spinno that made the comment about anticyclones and china vessels. My response still applies.
     
  14. spinno

    spinno Well-Known Member

    I'm still mystified by all the numbers. I'm sorry for your frustration, but it appears everyone has got an idea and everyone believes it's the right one.
     
  15. swanseadave

    swanseadave Well-Known Member

    Having reread the thread I still fail to see why it`s such a big issue.It seems trivial in the broader scheme of things.

    Just my observation.
     
  16. spinno

    spinno Well-Known Member

    I was tempted to say it's a bit of a gig gle do you think people might be offended and byte back
     
  17. IvorETower

    IvorETower Little Buttercup

    OK.... some years ago my parents bought a new carpet for their bedroom; let's say it was 12 ft wide and their room was 11ft3in wide. When the carpet was delivered, we cut 7 inches off, leaving us just 2 inches to trim to fit the skirting board when we laid it.
    When we did indeed unroll it, there was no need to trim anything off..... we then measured the carpet and discovered in the above terms, that we had received short measure... except that when we questioned this with the carpet shop, we were told of a thing called "tolerance"..... and 3 inches per yard was the industry standard, hence what we had was "in specification" even if technically it did not meet the sales description.
     
  18. swanseadave

    swanseadave Well-Known Member

    Possibly........ :eek: :D :D :D :D
     
  19. MickLL

    MickLL Well-Known Member

    Now help an old fool.

    I have a 1GB card that says that it has 1024655360 bytes - but it says that's 977MB.

    Why isn't it 1GB. Have I been oversupplied with bytes?

    MickLL
     
  20. Roy5051

    Roy5051 Well-Known Member

    1GB (1,000,000,000 bytes) will show 977MB on a computer (including a digital camera) for the reasons given above.

    Why you have 24,655,360 extra bytes, I don't know.
     

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