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USB FAQ is a comprehensive resource on the technology interface behind computer peripherals and digital storage. Discover the form and function of USB as well as gain awareness of flash drive features currently in the consumer marketplace. Do you have a USB question? Please submit your inquiries so that we can enhance your site experience.

[1] General Information

[2] Technical Information

[3] Operation and Use

[4] Copying

[5] Custom Flash Drives

[6] Security

[7] Troubleshooting

[1] General Information

[1.1] What is USB?

USB (Universal Serial Bus) is a interface technology, consisting of a serial bus, that connects and transfers data between a host computer and peripheral devices. According to an issue of 1394 Newsletter published by the Information Gatekeepers Inc, USB was originally designed to integrate computers and telephones, USB operates under a master/slave scheme to communicate between the host and the peripheral.1 Utilizing a true plug-and-play concept, the technology provides easy connection and configuration of peripheral devices without opening the computer. Depending on the device's data requirements, USB has low speed to super speed capabilities. Since its inception, USB has had four major consumer versions: USB 1.0, USB 1.1, USB 2.0 and now USB 3.0.2

[1.2] What is a USB flash drive?

A USB flash drive is a removable, portable device with varying storage capacities that uses flash memory for data storage and a USB connection for data transfer between the USB flash drive and a host device. An average flash drive weighs under an ounce. USB flash drive data can be removed or rewritten thousands of times, operating when plugged into a computer's USB port.

[1.3] What can you do with a USB flash drive?

The primary function of a USB flash drive is data storage. Video, audio, pictures and other types of files can be stored on flash drives for professional or personal applications. As this storage medium grows in popularity, more brands and businesses use flash drives as a promotional tool.

[1.4] Are USB drives waterproof?

That depends. Some manufacturers produce waterproof flash drives to enhance their durability. Many users attest to their flash drives holding up to laundry cycles; however, you will want to check your own flash drive's specifications and warranty before attempting, which is not advisable. There is no reason to actively tempt fate. Be advised that you should never plug a wet flash drive into a USB port.

[1.5] What is the largest drive available today?

Currently, the largest capacity consumer USB flash drive available today holds 256 GB. This capacity is as large as some computer hard drives. By estimation, this translates to the storage of more than 150,000 photos or more than 120 feature length movies. As of writing, Kingston's Data Traveler series has the only 256 GB drives. Kingston will soon be knocked off the podium by Transcend who developed a 2 TB drive; however, the drive is not available yet because it is waiting for international standards approval.4

[1.6] What is the most secure USB drive on the market?

Arguably the most secure USB flash drive on the market today is the Ironkey USB drive. The Ironkey has 256bit hardware encryption, password protection, virus protection, physical tamper detection, as well as many others. It is the only flash drive on the market today to pass level 3 FIPS 140-2 security.

[1.7] What is the most expensive USB drive ever produced?

While many sites erroneously state that White Lake's gold USB is the world's most expensive USB drive at 3,500 USD, this USB is only the fraction of the cost of others. Currently, the world's most expensive USB flash drive is Mii Stor's ICE+, which sells for 15,000 GBP. It has a 8 GB drive with a platinum case and is set with 462 5.10ct diamonds!5 The runner up is a Toshi Sotaji designed 16 GB drive sold by Solid Alliance called the Mnemosyne. It is engineered as an aluminum puzzle cube that holds a flash drive inside of it. Surprisingly, the capacity is only 16 GB. The Mnemosyne can be yours for more than 10,000 USD.6 An honorable mentioned is the Gresso Enigma, which is only 6,400 USB. It's 200-year-old African Blackwood shaped like a star with diamond and gold, but the real selling point (if you're in the market) is that it has a 192 GB capacity.

[1.8] How much does a USB drive cost?

The cost of an average flash drive depends on its storage capacity. The price can likely range anywhere between $5 for a 2 GB flash drive to $750 for a 256 GB drive.

[1.9] What are some other common names for flash drives?

The USB flash drive goes by a variety of synonyms that include: jump drive, thumb drive, keychain drive, memory stick, memory key, pen drive, data stick, USB drive, USB dongle, USB stick.

[2] Technical Information

[2.1] Who invented the USB flash drive?

While there is certainty that Ajay Bhatt of Intel and the USB-IF (USB Implementers Forum, Inc) developed the USB technology, controversy surrounds who first invented the USB flash drive. Both Trek Technologies and Netac Technology hold patent claims to the device in different countries and have brought lawsuits against other companies.7 However, many consider Dov Moran and the team at M-Systems (since acquired by SanDisk) to be the first. They patented the device in 1998 and in 2000 IBM began selling the 8 MB device in North America under the name, "DiskOnKey." Development for the flash drive as we know it today happened simultaneously in 2000 with Trek technology, IBM and Lexar.

[2.2] What are the parts of a USB drive?

There are three primary parts to a USB flash drive: the board, which includes the metal USB connector, the memory storage chip of NAND flash and the controller chip.

[2.3] What does the controller do?

The controller is responsible for operating the drive's commands, such as reading and writing.

[2.4] What is the difference between SLC and MLC memory?

They are varying grades of flash memory. SLC (single layer cell memory) stores one bit value per cell and MLC (multi layer cell memory) stores multiple bit values per cell. While MLC has a greater density for storage and lower cost per bit, SLC typically has greater endurance with 100,000 cycles versus MLC's 10,000 cycles. SLC can also operate at higher temperatures.

[2.5] Are all USB drives the same?

Not all USB drives are the same. USBs come in many different sizes, capacities, colors, shapes, materials, and quality levels that it is safe to say that almost no USB is the same as another.

[2.6] What is the difference between USB 1.1, USB 2.0, and USB 3.0?

The primary difference between each version is data transfer rates. USB 1.1 could operate at 12 Mbit/s and 1.5 Mbits/s. USB 2.0 can operate at 480 Mbit/s in addition to the slower speeds. USB 3.0 is backward compatible and can operate up to 4.8 Gbps. USB 3.0 also carries four additional wires than previous versions for bidirectional data transfers.

[2.7] What sizes of USB drives are available?

16MB, 32MB, 64MB, 128MB, 256MB, 512MB, 1GB, 2GB, 4GB, 8GB, 16GB, 32GB, 64GB, 128GB, 256GB.

[2.8] What is the life expectancy of a USB drive?

The life expectancy depends on the number of read and write cycles it endures. Each lifespan can vary depending on the quality of the drive but it is safe to say they achieve anywhere between 10,000 to 100,000 cycles.

[2.9] What are the read/write speeds of a USB drive?

The read and write speeds of flash drives vary from vendor to vendor. USB 2.0 drives can read anywhere from 14 to 34 MBps for read speeds and 4 to 28 MBps for write speeds. The newer USB 3.0 flash drives can achieve up to 80 MBps read speeds and 60 MBps write speeds.

[2.10] What is a Tier 1 drive?

Tier 1 refers the the quality of the flash drive itself. There are a wide range of qualities concerning flash memory ranging from tier 1 through tier 3. Tier 1 flash is the most durable, reliable, and highest performing memory. This is also sometimes called Class A memory.

[2.10] Is USB 3.0 backwards compatible?

Most of the time, yes. The backwards compatibility of a USB 3.0 device depends on the manufacture. The certification office does not require USB 3.0 devices to work on USB 2.0 computer system; however, most manufactures produce devices to be backwards compatible to capture a larger percentage of the their respective market.

[3] Operation and Use

[3.1] Will USB drives replace CD / DVD optical media?

It remains to be seen whether USB drives will replace discs, as it performs many of the same storage functions as optical media, but in a more portable, transferable format. However, discs continue to be a popular archiving and storage medium.

[3.2] What are some advantages of USB drives?

The main advantages of USB flash drives are their re-usability, flash memory, portability, and the USB interface. Unlike optical media, data on USB drives can easily be changed, deleted, or added without the lengthy setup of data transfer for burning discs. Because of the flash memory, they do not have moving parts, which eliminates the chance for mechanical failure of component parts. They are portable, compact for their storage capabilities and have minimal power requirements. Also, the universal availability of USB connections on computers allows the device to be plugged into any modern computer without the need of an intermediate interface.

[3.3] What are some disadvantages of USB drives?

The disadvantages of USB flash drives include: easily lost due to small size, a lack of write-protection and the fact that unprotected drives are prone to getting malware or spreading it.

[3.4] Which Operating Systems support USB flash drives?

USB flash drives can be used with nearly any OS including Windows, Mac and Linux.

[3.5] Are USB flash drives compatible with Apple Macintosh devices?

USB flash drives are compatible with Apple computers and a majority of the devices support a USB connection via a 30-pin proprietary connector that is used for iPhones, iPods and iPads. A problem may occur if a USB flash drive is formated in the NTFS file system, which is basically unreadable to the Mac mainframe. In this case, the USB flash drive would have to be reformatted.

[3.6] Do video game consoles support USB devices?

Some video game consoles support USB devices, most notably Xbox 360 and PS3.

[3.7] What is so special about U3 flash drives?

U3 flash drives are able to launch a Windows-friendly menu that allows for portability with your applications. The U3 program provides extra security, personalized preferences and user management.

[3.8] What does zero-fill mean?

Zero-fill is a method that completely erases a storage device, such as a USB flash drive or a hard drive. When you delete data from the hard drive, all it does it delete the file from the registry. In essence, all your files are series of 1s and 0s. The registry keeps track of which 1s and 0s belong to files and how they they should be read. Deletion of a file marks the 1s and 0s as unallocated space so when files are created or moved, this unallocated space becomes used. Therefore, after your file is deleted it is still there and can be recovered, but as you use the computer more, new files use the old 1s and 0s until no one is able to recover the old file. However, there is a lag between when the file is deleted from the registry and when it is absolutely gone from your computer. Zero-fill will delete the data by not only deleting the registry, but it will scramble all the 1s and 0s so the file is unrecoverable.

[3.9] Why should I zero-fill a storage device?

When files are deleted from a storage device, they technically are deleted only from the registry and can be fully or partially recovered for a period of time. Depending on the sensitivity of the data, its ability to be recovered represents a security risk to certain people so they use zero fill to completely remove the file or files and the risk.

[3.10] Why does a USB drive get hot?

A USB flash drive heating up is a common occurrence. While the drive does not have moving part, the transfer and modification of files on the USB drives require electricity, which emits small amounts of heat. The material the drive is made from will determine how hot a drive can get because metal conducts heat better than plastic, causing metal drives to reach higher temperature. A drive in normal operation will not become hot enough to either damage the USB drive or harm you. However, if it does burn you, then the USB port may be defective or a component on the USB drive has failed.

[3.11] How do I make mass copies of USB drives?

To truly produce mass copies, you will need a USB duplication tower, like CDs and DVDs. These towers are now readily available on the market. Most towers are easy to use, requiring the operator only to plug in the master into a specific port, plug in the blank drives into the other ports, and press "copy."8 The two major towers on the market are Accutower Flash and Nexcopy.

[3.12] How do I partition a USB drive?

To create a standard DISK drive partition on a USB drive, you can either use the disk utilities that come with your operating system or you can use specific partition management software; however, if you want to create an optical DISC drive partition on your USB, like the ones on SanDisK drives used to reproduce the the autorun function, you will need specific partitioning software with that capability.

For Windows, right-click on "My Computer" and select "Manage." The "Computer Management" will open and then go to "Disk Management" in the list. From here, you can change create and delete partitions among other things.

For Mac, open the "Applications" folder and go to "Utilites." From here, you can open the "Disk Utility" program and manage your partitions.

[4] Copying

[4.1] How can I copy the contents of a USB drive to another drive?

The contents of one drive can be copied to another through the use of a USB duplicator. This piece of equipment places the source drive into a source port and blank drives into one or several ports that allow for data to be written. A standalone or software system will manage the copy process.

[4.2] What is the fastest way to copy USB drives?

The fastest way to copy a USB drive is through the use of a flash drive duplicator, which can be purchased for at-home use or outsourced to a flash drive duplication service.

[4.3] Do USB drives support Auto Run functionality?

Yes, USB flash drives support Auto Run functionality. It allows preloaded data to run automatically once it's plugged in. It does not require the user to take action to open up a specific file.

[4.4] Why doesn�t my Auto Run work on a Macintosh?

Unfortunately due to security concerns, Macintosh computers do not support an Auto Run feature. The reason they don�t is because in the event that a user's flash drive becomes infected with a virus, spyware, or malware, the Auto Run feature would more than likely instantly infect the host computer once inserted. By having Auto Run disabled, the user must physically open the USB drive to see its contents.

[5] Custom Flash Drives

[5.1] Can I get a custom shaped USB drive made somewhere?

Yes. You can quite easily purchase custom USB drives from suppliers and resellers. If they offer custom printing services, they will likely personalize the shape as well. You will consult with a USB flash drive company's art and production departments to design the drive you want. The best thing is to check company websites and call to see what each can offer.

[5.2] What shapes are available?

You dream it up, a custom service company can likely make your design happen. There are no limits to the shape you can use, so long as it is not detrimental or hinders use in a USB port. Food, geometric shapes, landmarks and people are just the start of shapes that you can use.

[5.3] What materials do I have to choose from?

The most common USB flash drive materials include: plastic, metal, wood, rubber and epoxy.

[5.4] How much does it cost to get a customized flash drive?

The price of your custom flash drive depends on a number of factors: the storage size, the type of material or print process used and the complexity of the design. Ordered in bulk, these drives can start as low as $3.50 each for a 1 GB drive. As flash drives become more popular and more efficient ways are discovered to produce them, prices will continue to drop.

[6] Security

[6.1] Can my USB flash drive get a virus?

USB Drives can get viruses as well as spyware or malware. In fact, a large portion of infected computers are infected through the use of a USB flash drive unknowingly by the user. On Windows 7 and Macintosh computers, the Auto Run feature has been disabled by default to help prevent the spread of viruses and other harmful software from infecting the host computer.

[6.2] Can I protect the contents of my USB drive from being deleted?

There are actually several different ways to prevent information from being deleted. The first method is to create a Read Only Partition. In a Read Only Partition, a section of the USB flash memory is reserved for specific files and is told that this section is meant to be read only.

The second method is to create a CD partition on the USB drive. This method works almost identical to the first method, with the one exception that a CD partition can Auto Play when inserted into a computer. Both methods prevent a user from deleting or manipulating the files, but do not stop a user from copying the information.

[6.3] How do I encrypt my USB flash drive?

You can use a number of encryption applications, some provided by the manufacturer of the flash drive. The software essentially allows you to create a protected volume on the drive with a set of passwords. You choose the encryption algorithm. Only those with the correct password can access, add or remove data from the protected partition.

[6.4] How can a USB steal PC passwords?

First off, the USB itself cannot steal passwords, but programs on the USB can. An ethically challenged individual could steal PC passwords using a USB with a couple of different programs. These programs will generally steal any saved passwords by breaking into and copying the documents where passwords are stored. USBThief is specifically designed to be easily installed on a USB and will automatically steal passwords. Other options include making a autorun file that opens software designed to get passwords from programs like Internet Explorer or Microsoft Outlook.

[7] Troubleshooting

[7.1] Why do I get an error message that says "This USB device can perform faster if you connect it to a Hi-Speed USB 2.0 port"?

This message suggests that you lack the correct high speed connectivity to make your devices work. You may need to go to your computer manufacturer's website and install USB drivers or back up your data and restore your computer to its original default settings.

[7.2] Can I recover something that I accidentally deleted from a flash drive?

The good news is that most files remain on the drive, even after being "deleted." To retrieve lost information, you can use data recovery software that you can purchase or download online for free. This software will scan your drive and extract lost files. Another option is to use professional flash drive services to retrieve it. Neither method provides a 100 percent guarantee, but are the best options in hopes of recovery.


1. Pan, Hui, ed. 1394 Monthly Newsletter 2, no. 4 (April 1998). [back]
2. Mitchell, Bradley. "USB - Universal Serial Bus." Guide. (accessed May 5 2011). [back]
3. "DataTraveler 310." Kingston Technology. (accessed April 27 2010). Note: please contact us if you find a larger drive. [back]
4. Staff Writer. "Transcend Showing Off 2TB USB 3.0 Flash Drive." All USB Blog (accessed September 1, 2011) [back]
5. Laszlo, Arthur. "The World's Most Expensive USB Drive". All USB Blog (accessed June 10, 2011) [back]
6. USB Expert. "World's Most Expensive USB Flash Drive." Premium USB Blog. (accessed May 30, 2010) [back]
7. Deng, et al. 2004. Electronic flash memory external storage method and device. U.S. Patent 6,829,672, filed October 13, 2000, and issued December 7, 2004. [back]
8. Here is a video demonstrating how to use an Accutower Flash: Premium USB Video Team. April 2010. "Accutower USB Flash Drive Duplicator Demo by cdrom2go & PremiumUSB." YouTube. (April 5, 2011). (accessed June 5, 2010) [back]

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