The 32GB capacity of this SanDisk Ultra SDCZ48-032G-A46 flash drive provides ample room to store photos, music, videos and other files. The USB 3.0 interface and up to 80MB/sec. read speed make it easy to transfer files to and from your computer. (Ten times faster than USB 2.0 drives. Write speeds up to 10 times faster than Cruzer USB 2.0 drive.)* *USB 3.0 port required. Based on internal testing; performance may be lower depending upon host device.
In addition to providing reliable storage for information, many of these products come with security software that protects your personal data if you lose your device. The software secures files with 128-bit AES encryption and requires a password to unlock the stored information. It also features a drag-and-drop user interface that simplifies transferring and securing your data.
Flash drives can be defragmented. There is a widespread opinion that defragmenting brings little advantage (as there is no mechanical head that moves from fragment to fragment), and that defragmenting shortens the life of the drive by making many unnecessary writes.[37] However, some sources claim[38] that defragmenting a flash drive can improve performance (mostly due to improved caching of the clustered data), and the additional wear on flash drives may not be significant.
The memory in flash drives is commonly engineered with multi-level cell (MLC) based memory that is good for around 3,000-5,000 program-erase cycles,[40] but some flash drives have single-level cell (SLC) based memory that is good for around 100,000 writes. There is virtually no limit to the number of reads from such flash memory, so a well-worn USB drive may be write-protected to help ensure the life of individual cells.
“The solid state flash drive can theoretically achieve incredibly high transfer speeds, blurring the line between an external solid state drive and a flash drive,” our tester raved. He did note he was “unable to reach higher than half the listed read and write speeds.” However, he explained, “The Extreme Pro is still very fast compared to other USB 3.0 flash drives.” In the end, our tester recommended this flash drive “with the caveat that there's a good chance you won't see those 300+ MB/s transfer speeds.” He also added that for just a little more, you could invest in an external hard drive—if the ultra-compact form factor isn’t important in your buying decision.
These products use flash memory chips, a stable, high-density storage medium, to hold your data. They pack a huge amount of information into a compact form factor. Most thumb drives are less than 2 inches long and easily fit in a pocket, laptop bag or purse. Models with built-in covers protect physical connectors from damage, and select products feature rugged silicon and metal shells that enhance heat and water resistance.
Most USB flash drives do not include a write protection mechanism. This feature, which gradually became less common, consists of a switch on the housing of the drive itself, that prevents the host computer from writing or modifying data on the drive. For example, write protection makes a device suitable for repairing virus-contaminated host computers without the risk of infecting a USB flash drive itself. In contrast to SD cards, write protection on USB flash drives (when available) is connected to the drive circuitry, and is handled by the drive itself instead of the host (on SD cards handling of the write-protection notch is optional).
Hardware designers later developed EEPROMs with the erasure region broken up into smaller "fields" that could be erased individually without affecting the others. Altering the contents of a particular memory location involved copying the entire field into an off-chip buffer memory, erasing the field, modifying the data as required in the buffer, and re-writing it into the same field. This required considerable computer support, and PC-based EEPROM flash memory systems often carried their own dedicated microprocessor system. Flash drives are more or less a miniaturized version of this.
With wide deployment(s) of flash drives being used in various environments (secured or otherwise), the issue of data and information security remains important. The use of biometrics and encryption is becoming the norm with the need for increased security for data; on-the-fly encryption systems are particularly useful in this regard, as they can transparently encrypt large amounts of data. In some cases a secure USB drive may use a hardware-based encryption mechanism that uses a hardware module instead of software for strongly encrypting data. IEEE 1667 is an attempt to create a generic authentication platform for USB drives. It is supported in Windows 7 and Windows Vista (Service Pack 2 with a hotfix).[47]
