U3
Encyclopedia
U3 was a joint venture between SanDisk
and M-Systems
, producing a proprietary
method of launching Windows applications from special USB flash drive
s. 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. Applications that 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
created a successor called StartKey
.
SanDisk began phasing out support for U3 Technology in late 2009.
with a CD drive and standard USB mass storage device
attached.
The U3 Launchpad (LaunchU3.exe) is a Windows
program manager that is preinstalled on every U3 smart drive.
The U3 Launchpad automatically starts at insertion of a U3 enabled device.
and do not need to be installed on the computer.
s (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.
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.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."
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. 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.
active on the U3 USB hub controller, at which point the remaining software can be removed by a subsequent format, performed by the removal software itself. The removal tool is available from SanDisk's website.
U3 tool is another option that includes the ability to remove the virtual CD-ROM drive, as well as ways to reconfigure it to your liking.
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
.
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. Alternatively 3rd party disk encryption software
such as FreeOTFE
and BestCrypt
may be used to encrypt data.
Emulation of a CD-Rom drive: Emulating a CD-Rom drive allows booting PCs from U3 enabled Flash Drives which do not support booting from USB flash natively.
Removed user data, but not all of it: Recent files and programs had it listed.
Freezing with certain CD writing software: 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)
Proprietary format / closed platform: The U3 platform is a "closed" platform / proprietary format, and unavailable for developers. SanDisk
, the rightsholders for U3, ask for a 5% royalty from USB flash drive manufacturers who wish to implement the platform on their products.
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 embedded systems: 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 and can overcome this limitation, it still exists on many platforms.
SanDisk
SanDisk Corporation is an American multinational corporation that designs, develops and manufactures data storage solutions in a range of form factors using the flash memory, controller and firmware technologies. It was founded in 1988 by Dr. Eli Harari and Sanjay Mehrotra, non-volatile memory...
and M-Systems
M-Systems
M-Systems Ltd., was a Nasdaq-listed Israeli producer of Flash memory storage products founded in 1989 by Dov Moran and based in Kfar Sava, Israel. They were best known for developing and patenting the first flash drive, marketed in 1995 as DiskOnChip, and the first USB flash drive, marketed in...
, producing a proprietary
Proprietary software
Proprietary software is computer software licensed under exclusive legal right of the copyright holder. The licensee is given the right to use the software under certain conditions, while restricted from other uses, such as modification, further distribution, or reverse engineering.Complementary...
method of launching Windows applications from special USB flash drive
USB flash drive
A flash drive is a data storage device that consists of flash memory with an integrated Universal Serial Bus interface. flash drives are typically removable and rewritable, and physically much smaller than a floppy disk. Most weigh less than 30 g...
s. 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. Applications that comply with U3 specifications are allowed to write files
Computer file
A computer file is a block of arbitrary information, or resource for storing information, which is available to a computer program and is usually based on some kind of durable storage. A file is durable in the sense that it remains available for programs to use after the current program has finished...
or registry
Windows registry
The Windows Registry is a hierarchical database that stores configuration settings and options on Microsoft Windows operating systems. It contains settings for low-level operating system components as well as the applications running on the platform: the kernel, device drivers, services, SAM, user...
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
Microsoft
Microsoft Corporation is an American public multinational corporation headquartered in Redmond, Washington, USA that develops, manufactures, licenses, and supports a wide range of products and services predominantly related to computing through its various product divisions...
and SanDisk
SanDisk
SanDisk Corporation is an American multinational corporation that designs, develops and manufactures data storage solutions in a range of form factors using the flash memory, controller and firmware technologies. It was founded in 1988 by Dr. Eli Harari and Sanjay Mehrotra, non-volatile memory...
created a successor called StartKey
StartKey
Startkey is a USB flash storage device developed by Microsoft and SanDisk.-History:StartKey began in May 2007 when Microsoft and Sandisk made an agreement to provide unspecified software to replace U3 that was included on SanDisk flash devices.-Features:...
.
SanDisk began phasing out support for U3 Technology in late 2009.
U3 disk mounting: hardware emulation
A U3 flash drive presents itself to the host system as a USB hubUSB hub
A USB hub is a device that expands a single USB port into several so that there are more ports available to connect devices to a host system.USB hubs are often built into equipment such as computers, keyboards, monitors, or printers...
with a CD drive and standard USB mass storage device
USB mass storage device class
The USB mass storage device class, otherwise known as USB MSC or UMS, is a protocol that allows a Universal Serial Bus device to become accessible to a host computing device, to enable file transfers between the two...
attached.
- This configuration causes Windows disk management to show two drives:
- A read-only ISO 9660ISO 9660ISO 9660, also referred to as CDFS by some hardware and software providers, is a file system standard published by the International Organization for Standardization for optical disc media....
volume on an emulated CD-ROM drive with an autorunAutorunAutoRun and the companion feature AutoPlay are components of the Microsoft Windows operating system that dictate what actions the system takes when a drive is mounted....
configuration to execute the U3 LaunchPad, and; - A standard flash drive (FATFile Allocation TableFile Allocation Table is a computer file system architecture now widely used on many computer systems and most memory cards, such as those used with digital cameras. FAT file systems are commonly found on floppy disks, flash memory cards, digital cameras, and many other portable devices because of...
formatted) that includes a hidden "SYSTEM" folder with installed applications.
- A read-only ISO 9660
- U3 compliant applications can be (optionally) preloaded by manufacturers.
U3 Launchpad
Microsoft Windows
Microsoft Windows is a series of operating systems produced by Microsoft.Microsoft introduced an operating environment named Windows on November 20, 1985 as an add-on to MS-DOS in response to the growing interest in graphical user interfaces . Microsoft Windows came to dominate the world's personal...
program manager that is preinstalled on every U3 smart drive.
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. Applications include Opera and SkypeSkype
Skype is a software application that allows users to make voice and video calls and chat over the Internet. Calls to other users within the Skype service are free, while calls to both traditional landline telephones and mobile phones can be made for a fee using a debit-based user account system...
and do not need to be installed on the computer.
APIs
The U3 application programming interfaceApplication programming interface
An application programming interface is a source code based specification intended to be used as an interface by software components to communicate with each other...
s (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 2000Windows 2000
Windows 2000 is a line of operating systems produced by Microsoft for use on personal computers, business desktops, laptops, and servers. Windows 2000 was released to manufacturing on 15 December 1999 and launched to retail on 17 February 2000. It is the successor to Windows NT 4.0, and is the...
with Service Pack 4, Windows XP
Windows XP
Windows XP is an operating system produced by Microsoft for use on personal computers, including home and business desktops, laptops and media centers. First released to computer manufacturers on August 24, 2001, it is the second most popular version of Windows, based on installed user base...
, Windows Vista
Windows Vista
Windows Vista is an operating system released in several variations developed by Microsoft for use on personal computers, including home and business desktops, laptops, tablet PCs, and media center PCs...
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.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."
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. Prior to Sandisk's updated launcher software being released, Microsoft supported U3 by releasing an update to Vista (KB940199).Developer resources
Information on building U3 compliant applications and the U3 software development kitSoftware development kit
A software development kit is typically a set of software development tools that allows for the creation of applications for a certain software package, software framework, hardware platform, computer system, video game console, operating system, or similar platform.It may be something as simple...
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. 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 (the hidden "SYSTEM" folder), 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; the official U3 Launchpad Removal Software was available on the U3 website and disabled the virtual CD drive device, leaving only the USB mass storage deviceUSB mass storage device class
The USB mass storage device class, otherwise known as USB MSC or UMS, is a protocol that allows a Universal Serial Bus device to become accessible to a host computing device, to enable file transfers between the two...
active on the U3 USB hub controller, at which point the remaining software can be removed by a subsequent format, performed by the removal software itself. The removal tool is available from SanDisk's website.
U3 tool is another option that includes the ability to remove the virtual CD-ROM drive, as well as ways to reconfigure it to your liking.
Benefits
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.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
Computer virus
A computer virus is a computer program that can replicate itself and spread from one computer to another. The term "virus" is also commonly but erroneously used to refer to other types of malware, including but not limited to adware and spyware programs that do not have the reproductive ability...
.
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. Alternatively 3rd party disk encryption software
Disk encryption software
To protect confidentiality of the data stored on a computer disk a computer security technique called disk encryption is used. This article discusses software that is used to implement the technique...
such as FreeOTFE
FreeOTFE
FreeOTFE is an open source on-the-fly disk encryption computer program for PCs running Microsoft Windows, and personal digital assistants running Windows Mobile . It creates virtual drives, or disks, to which anything written is automatically encrypted before being stored on a computer's hard or...
and BestCrypt
BestCrypt
BestCrypt is a commercial disk encryption program for Windows and Linux, developed by Jetico.-Features:* BestCrypt can create and mount an encrypted virtual drive using AES, Blowfish, Twofish, CAST, and various other encryption methods...
may be used to encrypt data.
Emulation of a CD-Rom drive: Emulating a CD-Rom drive allows booting PCs from U3 enabled Flash Drives which do not support booting from USB flash natively.
-
- Using the open-source U3 Tool, a bootable ISO image can be copied onto the flash memory that will be presented to the PC as a USB CD-Rom drive to boot from lalala.
Criticisms
Numerous criticisms have been made of the U3 platform. These criticisms are:Removed user data, but not all of it: Recent files and programs had it listed.
Freezing with certain CD writing software: 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)
Proprietary format / closed platform: The U3 platform is a "closed" platform / proprietary format, and unavailable for developers. SanDisk
SanDisk
SanDisk Corporation is an American multinational corporation that designs, develops and manufactures data storage solutions in a range of form factors using the flash memory, controller and firmware technologies. It was founded in 1988 by Dr. Eli Harari and Sanjay Mehrotra, non-volatile memory...
, the rightsholders for U3, ask for a 5% royalty from USB flash drive manufacturers who wish to implement the platform on their products.
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
Kludge
A kludge is a workaround, a quick-and-dirty solution, a clumsy or inelegant, yet effective, solution to a problem, typically using parts that are cobbled together...
, 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 embedded systems: 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 and can overcome this limitation, it still exists on many platforms.
See also
- USB flash driveUSB flash driveA flash drive is a data storage device that consists of flash memory with an integrated Universal Serial Bus interface. flash drives are typically removable and rewritable, and physically much smaller than a floppy disk. Most weigh less than 30 g...
- List of portable software
- Portable application creatorsPortable application creatorsPortable application creators allow the creation of portable applications . They usually use application virtualization.- Creators of independent portable applications :...
- Live USBLive USBA live USB is a USB flash drive or a USB external hard disk drive containing a full operating system that can be booted. Live USBs are closely related to live CDs, but sometimes have the ability to persistently save settings and permanently install software packages back onto the USB device...
- Live CDLive CDA live CD, live DVD, or live disc is a CD or DVD containing a bootable computer operating system. Live CDs are unique in that they have the ability to run a complete, modern operating system on a computer lacking mutable secondary storage, such as a hard disk drive...
- Comparison of application launchersComparison of application launchers- Windows :- Linux :- Mac OS X :Although arguable, some consider desktop search tools to be application launchers as well, given their ability to quickly find and launch indexed applications. Such desktop search tools able to launch applications as well include Spotlight or Google Desktop...
- Windows To GoWindows To GoWindows To Go is a feature in Windows 8 that allows the entire system to run from USB mass storage devices such as flash drives and external hard drives....
External links
- PC Magazine reviews of the U3 Launcher, and programs (has screenshots)
- U3 Newbie Guide
- U3 Community (U3-Info: news, articles, forums, etc.)
- u3-tool, open source u3 managing tool