Data recovery from DECtape…

DECtapes were widely used in the 70s and 80s but were different from other open reel formats in that they were one inch wide and the reels were only 5 inches in diameter. DECtape was one of the most reliable tapes of it’s day and with the right tools, data recovery is still possible even from badly damaged media. However like most of the media of its time, it cannot be read on generic open reel tape drives and relies on the exact DECtape drive. Often finding a serviceable drive is more complicated than recovering the data! The DECtape drive served the purpose of a floppy disk before floppies were ubiquitous.

Even though it is tape it formatted data into fixed block sizes so they could be randomly read like a floppy disk. Hence the tape was able to use a normal file system, even though the seek time is heinously slow!

When a client approached us with a dozen DECtapes we dusted off our old TU-56 drive to host the tapes. Despite some handy repair work to decayed capstan wheels, wiring and capacitors, the drive would still not read the tapes. Thankfully the way the data is formatted on the tape meant we were able to build an emulator. With one of our vax drives and an interface board that we built ourselves, we were able to emulate the TU-56 drive and read the data.

This seems an awful lot of energy to recover only kilobytes of data for our client. Also the client had no idea what data was on the tapes, but they formed a part of their data centre archive. For compliance they needed to catalogue everything. Whilst the data they were seeking was not on these tapes, at least they were able to discount them.