Why do none of my memory devices show full capacity?

Animesh Jana October 18, 2012

Suppose drives in computer doesn’t show full space. Suppose my drive is of 30 GB, but it shows 29.9. Where did the remaining space go? Can anyone help me?

  1. Dave Rimmer
    October 26, 2012 at 3:40 pm

    The drive that you have is 30GB. The way that drive producers add them are as follows. They use 1000MB for 1GB but there is 1024MB for 1GB.
    So they sell your 30GB drive as being 30000MB when in fact it should be 30720MB . So this means that you have 720MB less that what you should have but it's just the way they are sold.

  2. dhanunjayarao chunduri
    October 20, 2012 at 2:15 pm

    1) Normally in the memory industry 1gb equals to 1000MB but in the computers it takes 1024MB=1GB .

    2) Recycle Bin occupies some of space from all drives for recover the deleted files.

    3) and lastly some will be firmware purpose.

  3. Raja Pradeep
    October 19, 2012 at 4:16 pm

    Hidden space is used by OS for storing settins, data, operating system files etc.

  4. Bruce Epper
    October 19, 2012 at 12:19 am

    There are 2 areas where error is introduced in the reporting of available drive space. First, most device manufacturers use base 10 math when computing sizes of storage media while most operating systems are using base 2 math which introduces an error of 73,741,824 bytes per gigabyte. Second, when a device is formatted, filesystem-specific overhead is incurred and some space is reserved for use by the system in tracking where files are stored, their names and other properties, etc. This also reduces the amount of space available for use for user files. Because of these sources of reporting error, a 1TB hard drive under Windows using NTFS will generally be reported as being 931GB in size.

    • Andrew Wright
      October 20, 2012 at 8:26 am

      A most excellent post on Hard Drive Overheads.

      This - Animesh, is the definitive answer!!!


  5. Alex Perkins
    October 18, 2012 at 10:45 pm

    It's capacity is often rounded, and also some space is taken up by recovery partitions that aren't shown.

  6. Adrian Rea
    October 18, 2012 at 8:04 pm

    Oh yes as ha14 says, there can be other partitions like to boot sector of a disk or a recovery section, which will not show as part of your C drive

  7. Adrian Rea
    October 18, 2012 at 7:59 pm

    A drive is often advertised as a number but this is often rounded to the nearest number. For instance 1 Kilobyte is 1024bytes (not 1000).
    Secondly If your pc says the disk is full, it may be leaving a tiny breathing space to allow it to amend files or defrag etc.
    Finally if it is 99.9% full, its near as damn it full, even if it is not exactly 100%, you would not be able to fit another file in as every file takes up a fair bit more than one byte.

  8. ha14
    October 18, 2012 at 7:41 pm

    well some will be for firmware, others will have hidden partitions for recovery purpose...

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