Thursday, August 30, 2012
IBM Digital Magnetic Tape Turns 60
Magnetic tape technology for analog, mostly sound, recording had been used for commercial uses since at least the 1930’s. Many different approaches to record sound with magnetic recording for were developed over the years since the first demonstration of magnetic recording on steel wires by Danish inventor, Vladimir Poulsen, sometime between 1893 and 1898. Note that an American, Oberlin Smith, described how magnetic recording could be done on magnetic impregnated thread or steel wire in 1888.
In the 1940’s German radio stations broadcast Hitler speeches from several radio stations at one time using the Magnetophone magnetic tape recorders, which used iron oxide coatings on plastic substrates. These analog magnetic tape machines led to the development of audio and video recording technologies after WWII by companies such as Ampex.
During my recent visit to the FAME studio in Muscle Shores, I was surprised to discover they are still using a 16 track audio recorder with 2-inch tape. They also had ProTools, but said analog recording is still desired by the very customers of this old-time recording studio. However, it is getting very hard to obtain raw tape for the recorder.
Univac introduced a metal substrate tape and tape recorder for computer digital recording in 1951. However with the introduction of lighter weight and more flexible plastic substrate magnetic tapes, combined with a vacuum column to control the tension that the magnetic tape experiences during use, the IBM 726 was a prototype of the modern digital tape recording system.
Since the 1950s there have been many generations of magnetic computer tapes of various widths and thickness and using various types of recording methods including multi-track linear recording (the technology generally in use today) as well as helical scan recording (like the recording in the old VCR video recorders) to full transverse recording (where the recorded information tracks are perpendicular to the direction of tape motion.
Over the years, since 1952, magnetic tape recording storage capacities have increased from 2.3 MB to 5 TB (an increase of over a million times) and much of the world’s digital information is kept on digital tape for long term archiving. It is estimated that more than 400 Exabytes of data now reside on digital magnetic tape.
Backup and archiving remain the biggest applications for digital magnetic tape although it is also used as a physical data transport device (as the old saying goes, you can ship more data on tape in a delivery truck over a shorter time than you can send electronically). There are several modern digital tape storage products in production, such as Oracle’s T10000 and IBM proprietary tape formats, but the most popular modern digital tapes are in the LTO tape format.
The LTO tape consortium (led by HP, IBM and Quantum) has a public tape product roadmap that will take magnetic tape technology out to about 13 TB of native (uncompressed) storage capacity. The current generation, LTO 5, has 1.5 TB of native storage capacity. According to Fujifilm and others in the industry, magnetic tape technology can eventually support storage capacities of several 10’s of TB in one cartridge. Much of these increases in storage capacity will involve the introduction of technologies pioneered in the development of magnetic disk drives.
In addition to a higher storage capacity than past LTO generations, LTO 5 also offers new architecture features such as the LTFS file system that turn magnetic tape into a directly addressable data source, like a hard disk drive. This assists in rapid access to the data on digital tape and is one of the key technologies to support the development of cloud based archive technologies such as the Permivault technology recently introduced by Fujifilm.
With total stored information growth exceeding 50% annual increases, high capacity, low cost storage technologies such as digital magnetic tape will continue to play an important role. Magnetic digital tape makes the digital society that we live in today accessible to more people than ever before and helps preserve this digital heritage for the future.
Modern digital magnetic tape turns 60 this year but despite its age, the technology looks like it is far from retiring. Like today’s modern workers we can expect this hardworking technology to continue to play an important role for many years to come. Me, I'm watching from the sidelines.