This is a simple guide for USB Flash Drives, such as those sold on eBay. Flash memory is 'non-volatile' ie data stored on a Flash Drive will be retained until overwritten by new data or the drive is formatted (all files erased).
Flash Drives come in various shapes & sizes and the smallest ones are usually described as pen drives. This has mainly come about by the introduction of Flash drives that look like and indeed act like a writing instrument.
These have now been developed further, so that (including the USB connector plug) the whole device can be as small as 3 or 4cm in length. There are even drives on the market that are not much bigger than a 1GBP coin! (a 1 Euro coin is almost the same size). These devices are designed to be carried in your pocket, or if supplied with a lanyard, around the user's neck - portability is the name if the game.
Capacity varies from as little as 256mb to as much as 64GB* (Gigabytes: 1 GB = 1000 megabytes) - which represents a sizeable amount of storage. Manufacturers will supply tables of data, showing how many photo's or minutes of music files can be stored per drive size. For example, a 4GB drive will hold approximately 1000 photo's (at a resolution of 5 mega pixels) - but the actual number will vary by brand and average file size.
All these devices, whether small or large in terms of capacity, are powered by the host device when plugged in via the USB port and typically operate on a tiny 3.3 volts. The drives require no external power source and the NAND technology used, means that data can be stored for up to 10 years! Also, in most cases, Flash drives can be read from and written to in excess of 100,000 times
Once plugged into a PC or Mac, the Flash drive can be accessed as a removable disk, with properties very similar to your Hard Disk, except that Flash memory does not have any moving parts, such as a platter or a read head. These are very useful for operating with a 'Netbook PC' which by definition is a relatively small, low capacity device.
You must not simply remove a USB Flash drive from its connection to your PC or Mac, as this may well corrupt the data held on your Flash drive. Worse still, you might damage the drive, rendering it unusable, or even cause the USB port on your PC or Mac to become inoperable, ie not recognize that a USB device is present. Sandisk USB drives and cards now have recovery software available but it is probably better to follow correct procedures in the first place
The latest operating systems, such as Windows XP, Vista and later, allow you to safely remove devices connected to your USB port without having to shut down. Just follow the instructions given by the "safely remove Mass Storage device" icon in your System Tray.
At the very least, if you are not sure, close your PC or Mac down first, prior to removing the Flash drive from the USB port. Corruption of data is the most common form of complaint made by buyers - this can easily be avoided by carefully following the basic rules. Read more in your Windows Help files or User Manual.
Most Flash drives will offer some form of password protection, so that private files can only be accessed by the intended user. In addition, there is usually some form of file locking capability, so the files cannot be accidentally erased (IMPORTANT however - see below).
Flash drives can be used in exactly the same way as fixed or removable storage, ie files can be written to or saved on the drive, read, modified, deleted, overwritten etc. In addition, the user can format the drive (in the same way as any other PC drive). CAUTION however, as formatting erases ALL data including any protected files or information!
The use of Flash technology allows data in a number of well known formats, eg mp3, mov, wav (audio & video), jpg, jpeg, gif, bmp etc (digital photo's and drawings, clip art etc). In fact virtually any type of file that might be stored on a PC or Mac can be written to or stored on a Flash Drive.
Read and write speeds will depend on the sophistication of the Flash Drive. Major brands, such as Kingston, Integral, PNY, Sony, etc. tend to have faster read/write speeds than unbranded or generic drives, 6-8mb/sec or more BUT you do normally have to pay significantly more. Listings on eBay will usually state high speeds as a feature of the particular drive being sold.
The principal non-academic use however, is for the storage of digital photo's, which can then be displayed on a PC (Desktop or Laptop), Mac (as for PC), or any type of media streamer/Home Cinema system etc, that has a USB port. MP3 (music) files, which are now commonly available via download sites on the Internet can also be stored and played back on any suitable device, including in the last few years, in-car-entertainment systems.
Because all of the file information stored on the drive is retained, then the data can be shared with any device capable of reading it an translating to pictures, documents or music etc.
Flash drives are very popular with students, who can save all their project data from their PC at college or uni and transfer them to a home system during term holidays etc.
E & OE
(c) 2006 -2011 MPRC. Revised 03 May 2011