Digital Tape

What is digital tape good for?

The fail-safe backup of choice for institutions is digital tape, in one of its many forms. One reason digital tape is preferred as a secondary medium is because it has a high capacity, and you can add more capacity cheaply once the system is in place. Digital tape can run in the background, without the kind of hands-on requirements of optical disk. You can also reuse digital tape, which makes it well suited for use as a rotating offsite backup. Digital tape is much less susceptible to viruses compared to hard drives.

Digital tape has a few important drawbacks. The first is that a modern tape system is costly to implement for the single user or small workgroup. The tape deck itself is expensive, as is a tape autoloader, if one is needed. Often, these machines can only connect to computers using relatively expensive add-on cards, like Fibre Channel or SAS. Additionally, there is a confusing array of tape formats some of which are proprietary and some of which are open source.

Digital tape is most attractive to a studio or workgroup that generates too much volume to consider Blu-ray as a secondary medium. If you need to back up hundreds of gigabytes a week, digital tape is probably the right technology. Tape is also the right choice for many workgroups that need to back up the work of multiple users.

Figure 1 LTO4 digital tape is the best current choice if you want to implement some kind of tape backup.

Which flavor of digital tape should I use?

As you consider a tape system, you’ll need to choose a particular flavor to commit to. You’ll be investing in a recorder and tape, and you’ll want to know that the data will be accessible even if the recorder you buy breaks in a few years. And the system you choose should allow for the kind of growth you expect in your media library without having to go to a new system.

Linear Tape Open (LTO) Ultrium is probably the best choice for the foreseeable future. It is an open format, meaning that no single company controls the production of recorders and tapes. Additionally, the LTO specification mandates that current recorders be backward compatible with two previous LTO versions. This makes it more likely to be readable in the future, should your recorder break.

LTO is also fast to read and write, uses high-capacity tapes, and can be set up for write-once capability so that old data is always protected. The LTO specification is currently in its fourth version, LTO-4. LTO-4 tapes can hold 800 GB of data and can transfer at the rate of 120 megabytes/second.