Support : Frequently Asked Questions
Support : Frequently Asked Questions

USB Flash Drives

Q: Why can't I have access to the advertised capacity of the USB Flash drive?
Q: How do I format the USB Flash drive?
Q: How do I protect a USB Flash drive with a password (Mac OS)?
Q: Why won't a drive letter show up in Windows XP for my USB Drive under "My Computer"?
Q: I have multiple USB ports in my computer, which port should I plug my USB Drive into?
Q: How do I convert my USB flash drive to a NTFS format?

USB Flash Drives FAQs

Q: Why can't I have access to the advertised capacity of the USB Flash drive?
A: Your USB Drive will have a smaller true capacity versus the advertised or marketing capacity due to the historical definitions of GB and MB, as well as Memory Management and Partition Accounting information utilizing some of the true capacity of your USB Drive. This discrepancy does not only apply to Flash Drives, but standard hard drives as well. Memory Management utilizes about 64KB out of every 1MB. The larger the card the larger the amount reserved. The following table shows the advertised capacity vs. the average true capacity.

Advertised Capacity Average True Capacity
64MB 61.2MB
128MB 120MB
256MB 241MB
512MB 495MB
1GB 984MB
2GB 1.91GB
4GB 3.82GB
8GB 7.59GB
16GB 15.1GB
32GB 30GB

Marketing or Advertised Capacity vs. True Capacity (Information provided by: wikipedia.org)

It is important to note that hard drive manufacturers often use metric definition of the prefixes "giga" and "mega." However, nearly all operating system utilities report capacities using binary definitions for the prefixes. This is largely historical, since when storage capacities started to exceed thousands of bytes, there were no standard binary prefixes (the IEC only standardized binary prefixes in 1999), so 210 (1024) bytes was called a kilobyte because 1024 is "close enough" to the metric prefix kilo, which is defined as 103 or 1000. This trend became habit and continued to be applied to the prefixes " mega," "giga," and even "tera." Obviously the discrepancy becomes much more noticeable in reported capacities in the multiple gigabyte range, and users will often notice that the volume capacity reported by their OS is significantly less than that advertised by the hard drive manufacturer. For example, a drive advertised as 200 GB can be expected to store close to 200 x 109, or 200 billion, bytes. This uses the proper SI definition of "giga," 109 and cannot be considered as incorrect. Since utilities provided by the operating system probably define a Gigabyte as 230, or 1073741824, bytes, the reported capacity of the drive will be closer to 186.26 GB (actually, GiB), a difference of well over ten gigabytes. For this very reason, many utilities that report capacity have begun to use the aforementioned IEC standard binary prefixes (e.g. KiB, MiB, GiB) since their definitions are not ambiguous.

Another side point is that many people mistakenly attribute the discrepancy in reported and advertised capacities to reserved space used for file system and partition accounting information. However, for large (several GiB) file systems, this data rarely occupies more than several MiB, and therefore cannot possibly account for the apparent "loss" of tens of GBs.

Q: How do I format the USB Flash drive?
A: To format the USB Flash Drive, use the following steps for your computer's operating system.

Important: If you have any files you want to save, be sure to copy them to another disk before you erase the disk they are on.

Windows
  1. Close any open applications, including anti-virus software, that may interrupt the format process.
  2. Double-click on the "My Computer" icon on the desktop.
  3. Right-click on the "Removable Disk" icon with the drive letter assigned to your Mobile Mini or Mini Flash Drive.
  4. With a Right-click, Select "Format" from the drop-down menu that appears.
  5. Optional: Type in a name in "Volume label" if you have more than one USB Flash Drive and prefer to assign names to differentiate them.
  6. Click on "Start" button. A warning notice appears that all data will be erased. Click "OK" button. The formatting will only take a few seconds, and a "Format Complete" notice will appear when the formatting is done.
  7. Your USB Mobile Mini or Mini Flash Drive should be recognized by your system at this point. You can return to using your drive as before.
Mac OS X
  1. Close any open applications, including anti-virus software, that may interrupt the format process.
  2. Open your "Applications" folder and then open your "Utilities folder.
  3. Double-click on "Disk Utility".
  4. Select the disk or volume in the sidebar, then click the "Erase" button.
  5. Click the Format pop-up menu, then choose a volume format.
    • Mac OS Extended (Journaled): Uses the Mac format (Journaled HFS Plus) to protect the integrity of the hierarchical file system.
    • Mac OS Extended (Journaled, Encrypted): Uses the Mac format, requires a password, and encrypts the partition.
    • Mac OS Extended (Case-sensitive, Journaled): Uses the Mac format and is case sensitive to folder names. For example, folders named “Homework” and “HOMEWORK” are two different folders.
    • Mac OS Extended (Case-sensitive, Journaled, Encrypted): Uses the Mac format, is case sensitive to folder names, requires a password, and encrypts the partition.
    • MS-DOS (FAT): Use for Windows volumes that are 32 GB or less.
    • ExFAT: Use for Windows volumes that are over 32 GB.
  6. Enter a name for the disk or volume.
  7. To prevent the erased files from being recovered, click "Security Options", use the slider to choose how many times to write over the erased data, then click "OK".

    Writing over the data three times meets the U.S. Department of Energy standard for securely erasing magnetic media. Writing over the data seven times meets the U.S. Department of Defense 5220-22-M standard.

  8. Click "Erase", then click "Done".
Q: How do I protect a USB Flash drive with a password (Mac OS)?
A: To protect a USB Flash drive with a password (Mac OS), use the following steps.

When you format an external volume, you can encrypt and protect the volume with a password. If you encrypt an external device, you must enter the password when you connect the device to your computer.

To encrypt and protect the volume with a password using Disk Utility, you must erase the volume first. If the volume contains files you want to save, be sure to copy them to another volume.

Important: You can encrypt your data without erasing it by turning on FileVault in the Security & Privacy pane of System Preferences. You can also encrypt a disk and protect it with a password without erasing it by Control-clicking the disk in the Finder and choosing “Encrypt [disk name].”

  1. Close any open applications, including anti-virus software, that may interrupt the format process.
  2. Open your "Applications" folder and then open your "Utilities folder.
  3. Double-click on "Disk Utility".
  4. Select the disk or volume in the sidebar, then click the "Erase" button. If you’re protecting an external volume, make sure it’s connected to your computer.
  5. Enter a name for the volume.
  6. Click the Format pop-up menu, then choose Mac OS Extended (Journaled, Encrypted).
  7. Enter a password when prompted.
  8. To prevent the erased files from being recovered, click Security Options, use the slider to choose how many times to write over the erased data, then click OK.

    Writing over the data three times meets the U.S. Department of Energy standard for securely erasing magnetic media. Writing over the data seven times meets the U.S. Department of Defense 5220-22-M standard.

  9. Click "Erase".

To change the password for your disk or partition, select it in the sidebar, then choose File › Change Password.

Q: Why won't a drive letter show up in Windows XP for my USB Drive under "My Computer"?
A: If you plug in a new USB Flash Drive into your Windows XP system and it does not show up under "My Computer" with a drive letter, you may have a conflict with another drive in your system. This tends to occur when a computer has multiple hard drives or CD/DVD drives and one of them if assigned to drive letter "H". To change the drive letter, you will need to open "Disk Management."
  1. Click "Start", point to "Settings", click "Control Panel", double-click "Administrative Tools", and then double-click "Computer Management." In the console tree under "Storage", click "Disk Management."
  2. Right-click the USB Flash Drive, and then click "Change Drive Letter and Path."
  3. To modify a drive letter, click it, click "Edit", click the drive letter you want to use, and then click "OK."

    Note: An error message may appear when you attempt to assign a letter to a volume, CD-ROM drive, or other removable media device, possibly because it is in use by a program in the system. If this happens, close the program accessing the volume or drive, and then click the Change Drive Letter and Path command again.

    If your USB Drive does not show up under "Disk Management" and there are drives already assigned to "H", you may need to change that drive letter first. Then plug the USB Drive back into the computer to see if it appears. Now change the drive letter on the USB Drive and then change the original"H" drive back to an "H."

    There is also a possibility that the desired drive letter for your USB Drive may have been turned off. By downloading and installing a Microsoft PowerToy called TweakUI, you will be given access to system settings that are not exposed in the Windows XP default user interface, including mouse settings, Explorer settings, taskbar settings, and more. Once you have installed this application, launch it through your "Control Panel" and click on the "My Computer" tab. If your desired drive letter is unchecked, check it at this time.
Q: I have multiple USB ports in my computer, which port should I plug my USB Drive into?
A: First, try plugging the USB Drive into the port that is most convenient for you. If your computer does not recognize your USB Drive, it maybe due to a lack of power provided from that specific port. USB ports located on keyboards or on the front of your computer may have insufficient power to run a USB Drive. Try using a port on the back of your system if the USB Drive is not being recognized.

Q: How do I convert my USB flash drive to a NTFS format?
A: To convert your USB flash drive to a NTFS format, following the below instructions:

Converting to NTFS Using Convert.exe:
A partition can also be converted after Setup by using Convert.exe. For more information about Convert.exe, after completing Setup, click Start, click Run, type cmd, and then press ENTER. In the command window, type help convert, and then press ENTER.

It is easy to convert partitions to NTFS. The Setup program makes conversion easy, whether your partitions used FAT, FAT32, or the older version of NTFS. This kind of conversion keeps your files intact (unlike formatting a partition).

To find out more information about Convert.exe:
  1. After completing Setup, click Start, click Run, type cmd, and then press ENTER.
  2. In the command window, type help convert and then press ENTER. Information about converting FAT volumes to NTFS is made available.
To convert a volume to NTFS from the command prompt:
  1. Open Command Prompt. Click Start, point to All Programs, point to Accessories, and then click Command Prompt.
  2. In the command prompt window, type: convert drive_letter: /fs:ntfs
For example, typing convert D: /fs:ntfs would format drive D: with the ntfs format. You can convert FAT or FAT32 volumes to NTFS with this command.

Important:
Once you convert a drive or partition to NTFS, you cannot simply convert it back to FAT or FAT32. You will need to reformat the drive or partition which will erase all data, including programs and personal files, on the partition.


For more information about NTFS, see: www.microsoft.com.