Long Term Archiving: Backup for Eternity - Part 3

Which storage media is best for long-term archiving? This week: Floppy disks and optical media!

There is an ongoing trend to more and more data being produced both by consumers and enterprises alike. But where to store all that new data? In the last two parts of this article series we covered the history and future of punch cards and tape as well as hard disk drives and SSDs… This week we will cover old floppy disks and optical media like CD ROMs and DVDs.

Here is an overview of what you expect today:

• Floppy disks and Iomegas Zip media and their drives have been strong for the early days of computing. But they since the only store a small amount of data, the needed hardware and drivers are mostly not available anymore and the media is either not being produced anymore or expensive, they are not suitable for modern use.
• CDs, DVDs and Blu-rays can make an addition to your storage needs if you need a fast, cheap and reliable backup media. For long-term archiving they are not useful because of their sometimes short life-span. Even though some can reach several decades of data storage, some don´t and only store their data for a couple of years.

From floppy disks to optical media

Many computer users who are over 30 years or older remember the days when they had to store their computer data on floppy disks or even on compact size data cassettes. Huge amount of data or applications had to be stored on many floppy disks which had to be then inserted into the computer one after another if another user (or buyer) wanted to install it on his computer. With the introduction of the first personal desktop, Apple computers as well as advanced computer graphic programs there was already a need for bigger storage even for consumer and small to medium businesses users. The storage capacity of this magnetic storage media was very low with only 1,44 MB of data space for a 3,5 inch disk which was introduced in 1984, the same year as the Apple Macintosh. The first floppy disks were invented in 1971, 8 inch in size and stored 80 kilobytes only as a read-only media. The first floppy disk user were able to store data on themselves could save 256 kb of data. Even though floppy disks are still available to purchase, it is rather a collectors item for old computers. Then and now some producers claim that a floppy disk can last ten to twenty years if stored correctly. However some of these media only last three to five years. It all depends on how good they were originally produced.

Trying to share graphic or layout data from one designer to another was almost impossible. Therefore another solution for a portable storage device had to be found. This why in the nineties Iomegas Zip Drives were a huge success. Simply put the disk drives were external devices with single magnetic hard disk drives covered by plastic cover. These disk were easy to handle, rather lightweight and had capacities of 100, 200 and 750 megabytes in total for each media. Many users however obviously did not take much care about the external device and the media itself. Therefore many complained about the "Zip-click-of-death," which was not more than a simple head crash still a common problem of hard disk drives who are falling on the ground, smashed or exposed to hits or beats. However this was not the main reason why the devices success came to an end, but because of the raise of the CD-ROM, followed soon after by the DVD.

The success of the CD and DVD

The idea of optical media is based on the idea and the need of a storage media that is immune to mechanical problems tape or a hard disk have: Since optical media is based on laser light the surface is not "touched" by any mechanical part unlike for example a tape drive were the tape is led through a roller, guides or read heads. A hard disk drive, too, can cause problems when some oft he many mechanical parts will fail. This is why a laser based optical storage was developed.

The Compact Disk (CD) first appeared at the 1977 Audio Fair as an optical storage for sounds and music. It was the result of many years of research of how to effectively record sounds. With the beginning of the digital age in the early seventies two companies – Sony and Philips – both tried to find a way to save and distribute music on a lighter and smaller media than the old vinyl discs or tape. In 1979 Philips demonstrated the first optical disk as well as the CD Audio Player. The final diameter was 12 cm and the resolution was increased from 14 bits to 16 bits. This combined effort of both Philips together with Sony set a new worldwide standard. However it took almost a decade that the CD was succeeding the old vinyl disc. By the beginning of the nineties almost no old vinyl discs were used for the publication of new music. The same happened to data storage. With the introduction of Multimedia Games and their increased amount of data, the first producers delivered their games on CD by 1991.

Normally an Audio CD or a Data CD is produced in a special factory – a pressing plant. The producer is giving his (audio) data to the CD pressing plant, who then creates a Master Disk. From this Master Disk the needed amount his then copied from. A typical CD can hold music up to 80 minutes or 650 MB of data.

Obviously no one without a serious business idea would go to a CD press plant to store his personal or business data on a such a commercially produced disk. That´s why the CD-R became a huge success soon after the breakthrough of the Audio CD after its invention in 1982. A Japanese company invented this format by 1988. Philips together with Kodak were the first producers of commercially available optical data disks and introduced the first CD-R and the first Picture-CD on the Photokina Photografic Fair in 1992.

The main purpose of a CD-R is store data on it – regardless if it is digital mastered music or files from a database or application. The technology behind the CD-R: The disk itself is a made out of polycarbonate on which several different layers were applied onto. One of this layers is a special organic dye layer. When data is burned on the CD-R the absorption and reflection properties of the smallest element of this dye – the pits – will be changed by the laser. When the data is read-out another smaller laser uses the changed reflection of the metallic reflection layer (either Gold or more often Silver) which is above the dye layer to convert it into an electrical signal aka bits and bytes. To protect both the dye as well as the reflection layer a CD-R normally another transparent paint layer completes the recordable side of disk.

Even though a CD-R (or a CD from a pressing plant) has 650 MB of space, which is enough for normal 10 to 12 tracks of music, it is not enough more movies or huge software programs. This is why DVDs were invented and introduced to the market in September of 1995. A year earlier two competing formats were introduced by Sony and Philips on one side and from Toshiba on another. This led to a confusion by the future costumers which one to buy to play their movies – a Multimedia CD (MMCD) from Sony/Philips or a Super Density (SD) player by Toshiba. However these players did not want to begin another "format war" like the one of VHS and Betamax video players in the late seventies and early eighties. Two other formats – the Video-CD and the LaserDisc – were not successful in the market, too. That is why they agreed on the Digital Video Disc or Digital Versatile Disc (DVD) as the new format as the new standard.

To keep it simple, the DVD is almost based on the same technology as the CD. Since the DVD was invented to store more data on the same diameter of the disk, the available space on the "plate" had to be used more effectively. That why the distance between the pits and the lands had to be reduced as well as that the pits and lands had to become smaller. This way more data could be stored on the disk. Additionally more sensitive laser are used in a DVD player/recorder to read-out or write data regardless if these are files or whole movies. A normal DVD stores 4,7 GB of data. However since its early days some more inventions have led to the dual layer DVDs (DVD-R DL) which has either two layers on the same side (DVD-9) and can hold up to 8,5 GB of data or for example the DVD-RAM which has two data layers of 4,7 GB on each side with a total of 4 data layers and 9,4 GB data space (DVD-10). Additionally there are also DVD-RAM (DVD-17) on the market which also have four data layers and can hold up to 18 GB of data. The last format however has not made it outside of Japan.

The typical life span of a DVD is almost the same as a CD: A recorded DVD will most likely – if stored correctly – last between two and five years – even though the producers claim that data on a DVD could last between 10 and 20 years.

The newest invention which actually made it on the market is the blu-ray. As the name suggests the Blu-ray uses a blue laser which uses a shorter wavelength laser light. This way the data can be written much closer on the disc and the laser point is much smaller. Additionally the transfer rate was also increased drastically so the data can read-out much faster. A Blu-ray comes in two version: A single layer and a double layer. The single layer disc can store up to 25 GB of data, while the double layer can store up to 50 GB. Triple or quad-layered Blu-ray discs can store up to 128 GB of data (based on the so-called BDXL format), but both the recorder which can write BD-R XL discs as well as the blank media are not common in both the US and Europe and have to be bought in Japan.

Since the invention of the CD many other concepts of optical media have been presented to the public – the Holographic Data Storage System or 3D optical storage where a third dimension is introduced to the storage media – however all of these concepts haven´t made it to market launch.

Conclusion: Since floppy disks are almost uncommon today, with almost no one still having a floppy disk drive in use, this storage media has only disadvantages: It stores almost no data, the media needs old hardware to run and is now expensive to buy.

Optical media however can be a additional storage media for both consumers and small to medium enterprises which only want to store a small amount of data as a backup. Optical media should always be stored inside a proper jewel case and in the dark. Additionally the disc should handled carefully so no scratches and dirt will destroy the data layers underneath the transparent (security) layer. It is wise to check the data frequently and to migrate needed data from an optical media after 2-3 years.

Picture copyright: Ontrack data recovery