Some manufacturers deploy physical authentication tokens in the form of a flash drive. These are used to control access to a sensitive system by containing encryption keys or, more commonly, communicating with security software on the target machine. The system is designed so the target machine will not operate except when the flash drive device is plugged into it. Some of these "PC lock" devices also function as normal flash drives when plugged into other machines.
Original flash memory designs had very limited estimated lifetimes. The failure mechanism for flash memory cells is analogous to a metal fatigue mode; the device fails by refusing to write new data to specific cells that have been subject to many read-write cycles over the device's lifetime. Premature failure of a "live USB" could be circumvented by using a flash drive with a write-lock switch as a WORM device, identical to a live CD. Originally, this potential failure mode limited the use of "live USB" system to special-purpose applications or temporary tasks, such as:
Audio tape cassettes and high-capacity floppy disks (e.g., Imation SuperDisk), and other forms of drives with removable magnetic media, such as the Iomega Zip and Jaz drives, are now largely obsolete and rarely used. There are products in today's market that will emulate these legacy drives for both tape and disk (SCSI1/SCSI2, SASI, Magneto optic, Ricoh ZIP, Jaz, IBM3590/ Fujitsu 3490E and Bernoulli for example) in state-of-the-art Compact Flash storage devices – CF2SCSI.
A recent development for the use of a USB Flash Drive as an application carrier is to carry the Computer Online Forensic Evidence Extractor (COFEE) application developed by Microsoft. COFEE is a set of applications designed to search for and extract digital evidence on computers confiscated from suspects.[48] Forensic software is required not to alter, in any way, the information stored on the computer being examined. Other forensic suites run from CD-ROM or DVD-ROM, but cannot store data on the media they are run from (although they can write to other attached devices, such as external drives or memory sticks).
Buoyed by its rocket-like speeds, the Extreme Go lives up to its name by transferring a 4K movie in less than 40 seconds — that's nearly 35 times the speed of a USB 2.0 drive and thanks to USB 3.1 hardware. Beyond its fast operation, the Sandisk looks as good as it performs with a sleek and slim package that's 2.79 x 0.84 x 0.45 inches in size and weighs only 4.8 ounces. The retractable connector makes it easy to store when not in use and it is backward compatible with any USB 3.0 or USB 2.0 port. Tucked inside its diminutive profile is a choice of 64GB or 128GB of storage capacity and it comes complete with data storage recovery in the event of an accidental file deletion.
The development of high-speed serial data interfaces such as USB made semiconductor memory systems with serially accessed storage viable, and the simultaneous development of small, high-speed, low-power microprocessor systems allowed this to be incorporated into extremely compact systems. Serial access requires far fewer electrical connections for the memory chips than does parallel access, which has simplified the manufacture of multi-gigabyte drives.
“The transfer speeds are satisfyingly fast for reading and writing all kinds of files, whether large HD videos or unsorted media folders,” our tester reported of this flash drive. He also liked the inclusion of the SecureAccess file encryption, although advanced features are an additional purchase. In terms of negatives, our reviewer called the plastic shell casing “flimsy and fragile” and observed that the transfer speeds are capped when the flash drive is plugged into a USB hub. Overall? Our tester was “more than satisfied with the transfer speeds, but would have appreciated a better, sturdier physical design.”
USB 2.0 flash drives have a transfer rate of up to 480Mbps, while USB 3.0 flash drives allow for transfer rates 10 times faster — up to 4.8Gbps. However, you can only take advantage of this higher speed if your device has a USB 3.0 port. Although USB 3.0 flash drives and other devices are backwards compatible with USB 2.0 ports, they will only operate at a USB 2.0 rate.
