U3

This article is about the computer company and design specification. For other uses, see U3 (disambiguation).

U3 LLC.

Type	Private
Founded	2004
Headquarters	Redwood City, California
Industry	Computer
Website	www.u3.com

U3 is a company producing a proprietary method of launching applications from specially formatted USB flash drives. Flash drives adhering to the U3 specification are termed "U3 smart drives". U3 smart drives come preinstalled with the U3 Launchpad, which looks similar to the Windows OS start menu and controls program installation. The method works with recent Microsoft Windows systems only. Applications which comply with U3 specifications are allowed to write files or registry information to the host computer, but they must remove this information when the flash drive is ejected. Customizations and settings are instead stored with the application on the flash drive.

Microsoft and SanDisk are working on a successor called StartKey.

1 U3 platform
2 Developer resources
3 Removal
4 Benefits
5 Criticisms
6 See also
7 Notes
8 References
9 External links

U3 platform

U3 disk mounting: hardware emulation

A U3 flash drive presents itself to the host system as a USB hub with a CD drive and standard USB mass storage device attached.^[1]

This configuration causes Windows disk management to show two drives:
1. A read-only ISO 9660 volume on an emulated CD-ROM drive with an autorun configuration to execute the U3 LaunchPad, and;
2. A standard flash drive (FAT formatted) that includes a hidden "SYSTEM" folder with installed applications.
U3 compliant applications can be (optionally) preloaded by manufacturers.

U3 Launchpad

U3 Launch Pad example.

The U3 Launchpad (LaunchU3.exe) is a Windows program manager that is preinstalled on every U3 smart drive.^[2]

The U3 Launchpad automatically starts at insertion of a U3 enabled device.

U3 applications

To be fully U3 compliant, an application has to be programmed to clean up its own data from the local machine. It must also be packaged in U3's special program format. U3 applications will only run from a U3 device. U3 programs can be downloaded from the U3 website and other places, such applications include Opera and Skype and do not need to be installed on the computer.

APIs

The U3 application programming interfaces (APIs) allows U3 programs lower-level access to USB flash drive, and to query the drive letter. The U3 APIs primarily allow developers who choose to use more of the power of U3 to control how their application handles things like device removal and saves data back to the drive such as configuration or documents.

Compatibility

The latest version of U3 launchpad supports Windows 2000 with Service Pack 4, Windows XP, Windows Vista and Windows 7.

Data can be accessed using any OS capable of reading from USB mass storage devices, unless the U3 device is password-protected.^{[note 1]}

Issues with older versions

Early versions of the U3 launchpad software had Vista compatibility issues (specifically the SanDisk Cruzer Titanium series with device numbers 2.17, 2.18, 2.19 and 2.20), although this problem could be eliminated by updating the launcher software.^[3] Prior to Sandisk's updated launcher software being released, Microsoft supported U3 by releasing an update to Vista (KB940199).^[4]

Developer resources

Information on building U3 compliant applications and the U3 software development kit, are available to registered developers at the official U3 website. Individuals must register (as a company) to download the SDK, or participate in the forums. ^[5] Applications that do not require installation steps in order to run can easily utilize U3 with little or no modification by taking steps to either not modify the host systems files or registry, or undoing all changes when the application terminates. A wizard which packages your distribution files and creates the special "manifest" file is provided.

Removal

Reformatting the drive will remove some of the software, but not all of it. The virtual CD-ROM drive cannot be removed by reformatting because it is presented to the host system as a physical device attached to a USB hub;^[1] the official U3 Launchpad Removal Software, available on the U3 website, disables the virtual CD drive device, leaving only the USB mass storage device active on the U3 USB hub controller, at which point the remaining software is removed by a subsequent format, performed by the removal software itself.

U3 Tool [1] is an open-source management tool (for Windows and Linux) that allows the locked U3 partition to be removed or replaced with any ISO image.

Benefits

A Toshiba 2GB TransMemory Flash Drive, sold with U3 functionality pre-installed on the USB drive.

Portability: This software automatically attempts installation of U3 components (U3 Launchpad) on the hard disk drive and associated System Registry entries on the Host Computer. Afterwards the U3 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, the initialization Host computer requires Administrative privileges and no need for administrator access privileges on subsequent computers.^{[citation needed]}
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 on other computers: New software can be installed to a U3 flash drive without the requirement for administrative privileges on the host computer.
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.^[6] Alternatively 3rd party disk encryption software such as FreeOTFE and BestCrypt may be used to encrypt data.

Criticisms

This section may contain original research. Please improve it by verifying the claims made and adding references. Statements consisting only of original research may be removed. More details may be available on the talk page. (September 2008)

Numerous criticisms have been made of the U3 platform. These criticisms are:

Freezing the computer: There is a possibility of slowing down or freezing Windows XP Pro if certain Windows drivers that are associated with high-volume data transfers to CD writers using certain CD/DVD burning software installed (Nero v7 and Roxio DirectCD^[7])

Proprietary format / closed platform: The U3 platform is a "closed" platform / proprietary format, and unavailable for developers^[8]. SanDisk, the rights holders for U3, ask for a 5% royalty from USB flash drive manufacturers who wish to implement the platform on their products.

Non-Windows issues: The U3 software and applications are designed for use with Windows. The effect of the U3 flash drive on non-Windows operating systems is variable – the emulated CDROM drive will appear as a read-only CD-ROM drive containing some Windows software on Mac OS and Linux. The U3 software takes up space on the flash disk, but can be deleted if this is really wanted by using the Windows/Mac uninstaller mentioned above.

Two drive letters: As a work-around to the lack of Auto-Play for Flash drives on older versions of Windows, the U3 software creates two drive letters (one which presents itself as a CD to allow Windows' auto-play to start the launcher, and another for storing user data). Although this is the only way to implement auto-start functionality on pre-Windows XP systems, it could be considered a kludge, and the extra drive letter created can be an annoyance. However, it is possible to prevent Windows from allocating a drive letter for the "CD drive" via the Windows "Disk Management" tool -- as long as the user has the appropriate rights/authority to do so.

Incompatibility with certain platforms: Some host systems – such as photo kiosks, consumer electronics, and other embedded computing devices – cannot correctly mount U3 "smart drives." The problem may arise because the emulated CD-ROM is the first drive presented to the host system. As such, the device is detected as a CD-ROM drive or not at all. Although some newer photo kiosks are U3 aware^[9] and can overcome this limitation, it still exists on many platforms. In embedded systems, where program memory is limited, it may be very costly in terms of system resources to make a device U3 aware. In such cases it is far more logical to leave this functionality out.

Free Software no longer available: Software that is advertised as "Free" at the U3 download website directs the user to 'Rapid Share' where the free option is always unavailable and the page redirects to one offering paid service account. There are also many previously "Free" U3 softwares that are no longer free. Some Trial software has already expired once downloaded.

Notes

^ U3 Launchpad Application, SanDisk.com. "If the OS in question can normally see ordinary USB flash drives, then the U3 smart drive removable mass storage area (domain) should still be available for standard file system activities unless it is a private area protected by a password."