Article, February 2006
USB Flash Drives
by Brian K. Lewis, Ph.D. Sarasota PCUG, Florida
You may already be familiar with the small USB flash drives that plug into a USB port. However, you may know them by another name. Flash drives, JumpDrives™, Pocket drives™, Pen drives™, and Thumb drives™ are all names for the same thing. They are a solid-state medium for storing data, music, photos, and/or applications. Now there is also a new version, the U3 smart-computing platform, which allows the user to carry applications and data from one computer to another and to launch the applications on any USB equipped computer. Many flash drive manufacturers are already jumping on this bandwagon and producing U3 based drives. Since flash drives are growing in capacity, functions and speed, they will probably be important in your computing future. So let's take a closer look at them.
A flash drive consists of a solid-state circuit board inside a plastic casing. Most of these casings are strong enough to stand some substantial abuse. My one gigabyte (GB) drive has managed to fall on the floor several times and it “still keeps on ticking”, as the saying goes. It tolerates this kind of abuse because it has no moving parts. Imagine if this had been a magnetic hard drive with several spinning platters and a movable read/write head. Just one fall could knock it completely out of alignment and cause it to fail. So that is one advantage of the flash drive. Another is its portability. Flash drives are small and very light weight. Mine measures 2¾ inches by ¾ inch x ½ inch. They can easily be carried in a pocket or strung on a lanyard or a key chain. The USB A type connector on these drives is frequently covered by a plastic cap that protects the connector.
Flash drives are powered directly from the USB port on the computer. When they are disconnected, the information stored in them is retained, not lost. The silicon chips used in flash drives are referred to as a form of nonvolatile memory. The RAM memory in your computer requires constant electrical input to retain information. The same is true of the BIOS chip. But flash drives retain information for greatly extended periods of time without any electrical input. Some estimates indicate data can be retained for periods of up to ten years, possibly longer.
Flash drives also have low power requirements, needing only the five volts and 100-500 milli-Amps provided by the USB port. However, their power demands are such that they generally will not run when plugged into a non-powered hub. You are always better off to directly connect the drive to the computer's USB port.
Flash memory was originally developed in 1988 and has seen considerable use in storage for digital cameras. (For the technically minded, flash memory is based on NAND gates where the transistors have two inputs and one output.) Some smart phones and PDA's are now using nonvolatile flash memory to retain information when the device is turned off. This reduces the drain on the device's battery. Flash drives are believed to work for up to 10,000 write/erase operations. However, some sources indicate that flash drives can survive for up to ten million operational or write/erase cycles. Even so, all this indicates that flash drives have a finite life span. To me, this life span seems to exceed that of a standard hard drive which is supposed to operate for up to half a million hours. In practice we know that hard drives generally fail much sooner than that. So a flash drive having a finite life span is really no different than a hard drive.
Flash drives now on the market have capacities of 3 – 4 gigabytes. Samsung has also announced a flash chip capable of storing 16 gigabits. (Note that this is bits, not bytes.) It would take 16 of these chips to make a 32 gigabyte drive. As an indication of what is coming, BitMicro has announced a 155 gigabyte flash drive!
Obviously, the flash drive has many advantages over other removable media such as floppy disks, CD-ROMs, ZIP disks and others. Unlike Zip disks, floppies and CDs, flash memory lacks moving parts, making it ideal as a simple solution, requiring only a port to interact with a system. It doesn't require any special hardware, it is smaller, more portable and it is not as likely to develop storage errors. Flash storage devices, compared to other storage media, are fast, high capacity, durable, and compact. Some computers can already boot from a flash drive that makes them an ideal replacement for bootable floppies or CDs.
Floppy drives are not even included in many new computers. As flash drives already exceed the capacity of CD's; they are becoming a replacement for them. Certainly they are more portable than a CD or a DVD and only require a USB port to run on any computer running Windows XP. They can be run on Windows 98 providing the manufacturer's specific driver is installed. Additionally, flash drives are not subject to scratches, dust, coffee or other liquid spills. In fact some have survived being passed through a washing machine! However, this is not recommended treatment for them. The popularity of flash storage devices may be attributed to their compact size, operating system compatibility, and their use of the standard USB interface.
With all of their capabilities, it is possible to foresee some applications for flash drives that may show up in a reasonable period of time. For example, if the read/write speeds can be increased to a level comparable to that of current RAM memory, flash memory could then replace RAM chips. If the cost of flash memory is also reduced then it could be used to replace the current computer hard drives. Think about what this would do to the size of computers and their power requirements. Think about replacing that 10,000 rpm hard drive and it's casing with a flash drive that can be connected to any computer's USB port. Certainly if we can produce 155 GB drives now, what will the capacity be in a few more years?
Earlier, I mentioned the new U3 (smart drive) specification for flash drives. This allows applications to be developed that can be stored and run from a flash drive. Software is already available for such drives. One such example is Mozilla's Firefox browser and their Thunderbird e-mail software. There are other applications that synchronize office files, folders and Outlook e-mail between a computer and a U3 flash drive. There is a version of Pass2Go that securely stores passwords, banking and credit card information on these USB smart drives. Also announced are photo management software and instant-messaging programs. Skype, a VoIP provider has announced a U3 version of their software that would permit voice calls over any computer with a U3 flash drive. The U3 flash drives and the associated software will run only on computers using Windows XP and Windows 2000. A Linux version is expected to be announced shortly.
The U3 smart drive contains software that functions as a “launchpad” to provide a menu of applications on the flash drive. It also has options for drive management and a link that leads users to a web site where they can obtain additional U3-compliant software. When the drive is removed from the USB port, the system software automatically shuts down any applications running on the USB drive and cleans out data fragments so no personal information is left behind on the computer. This U3 system software uses about 6 MB of the drive's capacity and loads within 30 seconds after the drive is plugged into the USB port. One result of this capability is that the U3 compatible flash drive can become your “personal” computer. Certainly it is even more portable than any laptop computer.
The day may come when your computer will be not much more than a motherboard, sound cards, wireless ethernet and USB ports. This reduces the moving parts to not more than a cooling fan, if that. All of the software and data will be on your flash drive. The face of computing is continuing to change. Fascinating isn’t it?
Dr. Lewis is a former university & medical school professor who has been working with personal computers for more than thirty years. He can be reached via e-mail: bwsail at yahoo.com.
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