U3 is a company producing a proprietary method of auto-launching applications from specially formatted USB flash drives. Flash drives adhering to the U3 specification are termed U3 smart drives.
“U3 smart drives” differ from traditional USB flash drives because they come preinstalled with the U3 Launchpad, which looks similar to the Windows OS start menu and controls program installation. The method only works with recent Microsoft Windows systems. Applications are allowed to write files or information to the host computer, but this information must be removed when the flash drive is ejected. Customizations and settings are instead stored with the application on the flash drive.
U3 flash drives are USB flash drives with a specific hardware and software setup:
- The hardware configuration causes Windows disk management to show two drives:
- A read-only ISO 9660 volume on an emulated CD-ROM drive with an autorun configuration to execute the U3 LaunchPad, and
- A standard flash drive (FAT formatted) that includes a hidden “SYSTEM” folder with installed applications.
- U3 compliant applications can be (optionally) preloaded by manufacturers.
The U3 Launchpad is a program manager that is preinstalled on every U3 smart drive, and is set to autoplay on insertion. A partition with the U3 Launchpad pretends to be a CD/DVD-ROM device in order to add USB mass storage device autoplay functionality on pre-Windows XP SP2 systems, or systems whose USB autoplay has been intentionally disabled.
The U3 Launchpad and U3 Applications runs on Windows 2000 SP4+, XP or newer. The U3 launchpad will work with Windows Vista as of version 220.127.116.11. Data will continue to be accessible from any OS capable of reading from USB Mass Storage Devices, unless the U3 device is password-protected. Compatibility issues have been noted as late as July 2007 under Windows XP Pro between certain Windows drivers that are associated with high-volume data transfers to CD writers and with certain drivers employed by digital video cameras, resulting in a full crash of the XP operating system. According to Sandisk’s community forums, as of Feb ’08 many users are still exhibiting Vista compatibility issues with U3 equipped flash drives regardless of the U3 launchpad version. Apparently this is related to specific hardware/firmware versions of the flash drive itself, as removing the U3 software will still not allow Vista to recognize the USB key. While Sandisk has claimed that a patch for the U3 is in the works, Microsoft has released an update to Vista (KB940199), allowing some users to successfully use the flash drive as intended. One of the affected USB Flash drives is the SanDisk Cruzer Titanium series with device numbers 2.17, 2.18, 2.19 and 2.20. By March 2008, SanDisk has released a new Launchpad update for these device versions of Cruzer Titanium that will make these devices fully compatible with Windows Vista. This will allow Vista users to both use the drive for data storage and the U3 functionality as they are used to under Windows XP, including the password protection.
- Software can be taken with all its personalized settings to any computer running a compatible version of Microsoft Windows (though no other operating system), with no need to install the software if not already there, or to use different settings and options, and no need for administrator access privileges.
- Software support
- Software is available from the U3 site, including, amongst others Trillian (instant messaging client), OpenOffice.org, FileZilla, Mozilla Firefox, and Skype. Some recent software compatibility concerns have surfaced, including incompatibility of newer Firefox versions with U3. However, updated versions of programs have made an appearance, like in the case of Mozilla Firefox.
- Ease of use
- Programs are run from the Launchpad, functionally similar to the Windows Start menu familiar to most users of Windows XP.
- No need of admin rights
- New software can be downloaded to a U3 flash drive without the requirement for administrative privileges on the host computer. However, removal of the U3 launchpad requires administrative rights.
- Virus protection
- Many U3 drives come with virus protection software which gives protection against being infected by or spreading computer viruses.
- Data security
- Most U3 drives on the market feature a security lock within the U3 Launchpad. This loads the CD partition first and can be user-configured to require a password to be entered; otherwise the data partition will not load. The drive is supposed to seal itself after a certain number of invalid password entries, requiring a reformat.
Sandisk and Microsoft have recently announced a partnership to develop a new line of portable USB-based hardware. This series, purportedly named StartKey, is expected to replace U3 by the end of 2008, making the U3 format obsolete.