What do whales and digitizing analog broadcast tapes have in common? A lot more than you'd think, explains Robert...
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Robinson, head librarian for National Public Radio in Washington, D.C.
Robinson, who's heading up efforts to digitize some 120,000 reel-to-reel tapes dating back to the 1960s, says that tapes made prior to the mid-1970s were coated with whale oil. But in 1972, Congress passed the Marine Mammal Protection Act, forcing tape manufacturers to switch to polyurethane.
Polyurethane, though, is no substitute for refined blubber, as it absorbs humidity. When you play the tape, the polyurethane builds up on the head and jams the drive mechanism. The result? "Tapes from the 60s and early 70s have held up pretty well," says Robinson, but later tapes are essentially unusable.
Luckily, reel-to-reel tapes can be salvaged by baking them for eight hours at 125 degrees, and then converted to digital format in the next 30 days.
So far, NPR has performed this rescue operation on tapes dating back to 1989. It is currently capturing them at full fidelity, saving them in the European Broadcast Union's .bwf format, and storing them on a writeable CD. Eventually, NPR will migrate the data on those CD-Rs to an LTO tape library it purchased from IBM, Robinson says.
In the television world, the move to digitize analog tapes has been accelerated by an FCC mandate to switch to a digital signal by 2006. There's no mandate to store the data digitally-only to transmit it-says Tom Inglefield, rich media market manager at StorageTek, but broadcasters figure that "since they have to get it into digital anyway, why not store it that way too?"
The kinds of storage systems broadcasters buy depends on whether they plan to actively work with the files, or simply archive them, Inglefield says. Current news footage is usually stored on a high-performance disk such as StorageTek's D280 2Gb/s Fibre Channel disk subsystem. But older, infrequently accessed broadcasts might be stored on a 9840- and 9940-based tape library. Particularly attractive for these kinds of environments, Inglefield thinks, is STK's new 9940B tape drive, which has 200GB of capacity. Assuming a 15Mb/s bit rate, that translates to 30 hours of broadcast on a single tape.
Other organizations are compromising between tape and high-performance disk, with ATA-based arrays. The Museum of Television and Radio in New York City, which is the official archive for over 117,000 television and radio shows and commercials, has slowly but surely begun to digitize some of its assets, storing them on a 3TB RAID subsystem from Nexsan Technologies.
Eventually, MTR's archive will probably swell to over 400TB, estimates Fred Cotton, the museum's director of engineering, which, with regular RAID system, "could get very expensive." But because of the way Nexsan engineers its RAID system-with ATA rather than SCSI disks-"all of a sudden it becomes cost-effective."