Long Term Archiving: Backup for Eternity

Which storage media is best for long-term archiving?

Since the early days of computers there is always the question which media is the best to store data for a very long time. Back in the sixties and seventies of the last century, when companies did buy the first computers, the storage media was – not of choice – but because of what the manufacturers where offering the magnetic tape.

These IBM or HP mainframe systems that would for example make all of the financial calculations of a small factory were so huge that they would easily fill a single room. In many cases, the employee – for example the financial director - would use a software program by the manufacturer to calculate the latest turnover, the expenses or the wages. Since in those days the RAM of the computers were really small, so were the programs. To store the outcome of these calculations or the final data magnetic tapes were used.

From punch cards to magnetic tape

Nowadays everybody thinks that this was the first method to store computer data. But this is not true: Actually the first computer storage media is hard paper – the so-called punch cards. Each character and figure was translated in a binary code and than punched into a standardized punch card. This punch card was then read out the next time by the computer device. Another variant of this method to store data were punch stripes. Stripes of paper much like the ones used in the supermarket except that the paper was thicker and had holes in it which represent the binary data.

This storage media was used until the late sixties by IBM or Texas Instruments until the magnetic tape was introduced around 1966 and gained wide acceptance by customers. While this hard punch card paper can last a long time – more than a couple of 100 years and at least 50 years (it depends on the paper the card is produced with– the storage space is limited: a single punch card on stores 80 byte of data.  A million punch cards would therefore store only 80 MB of data, while all these cards would reach 170 meters in height if piled up and have a total weight of 2500 kilogram. So no wonder that this storage technology did not have a future.

Tapes from the fifties until today

The first magnetic tapes that appeared on the market were IBM´s 7 track tapes for IBM 701 and IBM 702 mainframe computer in 1954. But the problem with these first mainframe computers were that were limited in their usage and could not cover the complete range of applications available by IBM. With the introduction of the System /360 this changed and so did the size of the tape used: It was now ½ inch (12.7 mm) and 8 tracks with one parity track could be stored on one reel. The introduction of the so-called 9 track tape.

Until today almost 50 different tape formats have been introduced into the market, with LTO 8 last year being the latest invention. What is common to all of these formats is that the data is stored linear onto the tape which has a layer of particles that is magnetizable. The tape media is still used today even though every year its death is announced. However producers of tapes promote their products with a durability of at least 30 years with proper handling and storage. Most experts say that the truth lies around 50 years. And Ontrack data recovery experts were recovering data from 7 track tapes a couple of years ago which were already 60 years old.

It took several years until the early eighties, when the first desktop computers were introduced by such manufacturers as Apple, Atari, Commodore, Osborne, Radio Shack, Tandy, IBM, NEC, Sinclair, Panasonic and others. With these smaller devices storing data again became an issue.  Thats when hard disk drives and floppy disks came into play…

Next week week we discuss the durability of HDDs and (Flash-based) SSDs… Stay tuned…

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