Why are we using USB Flash Drives?

Security and Flexibility

The current delivery platform for most Viridans packages is a USB Flash Drive (USB/FD).  The drives are fast; so there should be no noticeable reduction in performance when compared to installations which run from a hard drive.  And they are much faster than a DVD.  They are portable; so they can be installed to run on any computer provided the USB/FD is in place.  They are reliable; so as long as they are not physically damaged they will work for many years.  And, importantly for us, they are secure.  Each package is designed to run only from the device we supply so piracy should be more or less eliminated.

The decision to distribute our packages in this way has been a major one and the reasons are simple: increased security for us, increased flexibility for our clients.

For example, a common request from customers is for us to allow them to run a package from their home computer as well as one at work.  With the USB/FD version of our packages this is now possible.  He or she may install the package at home, at work or at a friend's place.  The USB/FD could even be lent to someone else, and we would have no problem.  The reason for this is that the package travels with the Flash Drive, it only works from the computer which it is attached to and only on the USB/FD we supply.

At workplaces where more than one staff member requires access to the package, the USB/FD version can be installed on several computers and the device can simply be moved from one to the other as needed.  With the DVD version the package would be restricted to a single computer.

Increased security for us means increased flexibility for the customer.

USB/FDs can wear out. Each time a file is saved or one is erased the life of the device is reduced a little bit.  Most authorities use the number of save/erase operations as the measure of longevity and for good quality, modern devices a figure upwards of 1,000,000 is commonly claimed before problems arise (tests on the devices we use has shown no problems after 2 million random, read/save cycles on a database file).  So they are robust.  

Important as this information is, it is largely irrelevant for the Wild Things and Just-a-Minute packages as all activity on the USB/FD is confined to reading data, not saving it.  Any saving (e.g. of temporary files etc) is done on folders created on the local hard drive.  For the FIS and VFD packages there are save/erase cycles when data is added or edited.  However, as each edition of these packages is used over a one-year period it is seldom that the number of additions and changes to the database would exceed 50,000 even in a very busy year.  

No company gives estimate of how many read cycles can be executed without error so we have tested the USB/FD devices we distribute by running 250 million random data reads on several new devices with one of our packages installed.  That is the equivalent of plotting between 350,000 and 4 million individual species distribution maps (depending on how many records there are for the selected species).  This is many times the activity that would be expected in the three-year life of any of these packages.  After the test the Viridans packages perform faultlessly and at the same speed as before.

Speed of Data Access

Early USB Flash Drives were rather slow, as were the USB ports in computers, and for many people that reputation has stuck.  Modern USB/FD (so-called USB 2) are much more rapid and for most users the speed of data access will be as good as that for a local hard drive (often better if the drive has a lot of files and hasn't been de-fragmented for a while).  Tests on the devices we supply have showed no discernable differences in speed of access for plotting distribution maps or searching for all the species in an area when the USB/FD is compared to a local hard drive.  In addition, tests on 1 million random access reads from the USB/FD, a local hard drive and an external USB hard drive, showed a slightly higher speed for the USB/FD.

Physical Wear-and-Tear

USB/FD devices are small, and many appear to be fragile.  However, there are no moving parts to get out of alignment, the circuitry is contained within plastic and metal casings and the devices we supply have fold-away covers to protect the socket.   There are many horror stories, on the web, of devices that last only a few months, ones that regularly corrupt data, and ones that are not recognised by the computer they are connected to.  We take these stories with a grain-of-salt. 

It is easy to corrupt a USB/FD if you copy large amounts of data to it and then remove the device without performing the 'safely remove' process.  A USB/FD drive can become unusable on a Windows platform if it is formatted on a Mac and sometimes if it is regularly moved between machines with different operating systems. Some devices are just poor quality (look out for cheap no-name brands) .  Some devices are treated carelessly so that contaminants enter the socket.  Others are heavily utilised for regular, complex data backups which may limit their life. And still others have had corrupted data written to them which may give the impression that the device is to blame rather than the data source.

We have found that if a quality device is kept relatively clean and free of physical damage, has uncorrupted data installed, and is used for a single purpose, a package, such as those we distribute, can be accessed daily for many years without problems.