The Use of Removable Media for Archival Materials
Background
For the last decade, the digital realm has steadily encroached upon archives and libraries, bringing with it collections that lean more toward electronic rather than paper records. These digital files have arrived in a variety of formats, ranging from ancient floppy disks to modern external drives. There is little existent literature that would recommend removal media of any type to be a worthy archival medium. Overwhelmingly, the consensus is for the migration of data off these formats and into archival repositories as obsolesces can occur incredibly fast; less than a decade in some cases. Digital records require periodic file format refreshment or migration into sustainable formats, which cannot be done (or is ill-advised) on records residing in magnetic and optical media.
Consequently, there is a valid need for a thorough understanding of the risks and challenges associated with migrating data off these mediums. A need for guidelines and best practices in order to set a processing precedent for existing and incoming collections. Yet, there is scant literature on how to successfully accomplish this. Sadly, among the literature, one fact holds true across the board. Successful migration diminishes as the age of the medium, or hardware necessary to read it, increases. While most studies focuses on the longevity of the medium, no doubt fueled by manufacturing marketing, the true risk lies in the scarcity of hardware necessary to read these formats. Much can be done in terms of establishing an ideal environment and housing for the media itself, but the corresponding hardware is much harder to preserve, with no "ideal" environment or protocols for its perpetuity. As a result, institutions face the very real danger of losing their electronic collections as the potential for access diminishes. Archives are therefore turning to digital forensics, a science involving the recovery and analysis of digital information, for assistance. Digital forensics provides tools and methodologies for ensuring authenticity by generating audit trails, write-protection and imaging with hash values. As digital materials continue to arrive with increasing volume, these digital forensic methodologies can assist with the bulk processing of data, allowing archivist to massage clusters of data rather than individual files.
Note: During the Summer of 2012, the Digital Curation division sponsored IMLS intern Miriely Guerrero. Miriely's internship focused on the analysis of Removable Media and the use of Digital Forensics in archives. The above paragraph was taken from her report. Download the full report (PDF)
Magnetic Media Summary of Recommendations:
- Floppy disks should be kept at a temperature of 64 degrees Fahrenheit - 68 degrees Fahrenheit, with relative humidity between 30 - 40 percent and sudden environmental changes should be avoided. Also avoid leaving disks close to heat sources, such as inside or on PCs. Disks are sensitive to magnetic fields and intense vibrations and should therefore be kept away from magnetic sources like cabinets with magnetic locks or lamps with metal bases.
- As the magnetic tape on a floppy disk is very fragile, and its source of protection (plastic casing on a 5 and one quarter inch disk or the metal shutter on a 3 and a half inchdisk) can be easily damaged, avoid writing on floppy disks with pencils or ball point pens, touching the tape, or affixing labels.
- Avoid paper or cardboard based storage slips as they can attract moisture and may raise the RH of the immediate surroundings of the carrier which may increase the rate of chemical decay, as well as generating fibers and dust. Instead store un-crowded disks vertically in Tyvek sleeves.
- When reading disks, always ensure the disk is write protected by sliding the write protection tab on the 3 and a half inch disk or taping the cut out on a 5 and one quarter inch disk. Do not say "okay" if prompted to reformat disk. It may take several tries to read a disk and occasionally there are problems with a computer reading the previous disk rather than the current disks (press F5 to refresh when this occurs).
- The use of a test diskette is helpful in determining whether read errors are a result of the disk or hardware. Also recommended is the purchase of drive alignment diskettes to ensure the floppy drive does not become misaligned, as this can occur gradually without warning of impending failure, and the purchase of a drive cleaning kit to prevent gradual residue build up on drive heads, as dirty surface error can lead to copy or read errors.
- The older the format the more in danger it is. Typically the medium outlasts the player as media life is considerably longer than the length of time most users maintain the hardware necessary to play it. Older formats are at higher risk than their younger counterparts (e.g. a 400 KB floppy disk is at higher risk than a 1.44 MB floppy disk).
Optical Media Summary of Recommendations:
- Discs should be kept at the ideal temperature of 64 degrees Fahrenheit with relative humidity at 40 percent. Sudden changes in temperature or humidity can cause optical disks to warp, but they can be flattened out with weights and time. Prolonged exposure to moisture or ultra violet light should also be avoided. Discs should always be stored vertically in their corresponding jewel cases, away from all booklets or paper. They should not be allowed to lean, nor stored too tightly on the shelves.
- Never flex, bend or place pressure on CD, even when removing from jewel case. Do not touch surface or scratch label side of disc. Instead always wear vinyl or nitrite gloves and hold disc by outer edge of center hole.
- Although mild solvents like quick evaporating isopropyl alcohol or methanol is permitted, in general the use of solvents, either for writing or cleaning, should be avoided as they can still affect the label and consequently the disc. For instance, ammonia based cleaners can cloud the disc surface. Use air puffer for the cleaning of media and hardware before attempting to use solvents. Never clean in a circular pattern and scratch filling tools should be used sparingly as they can increase uncorrectable error rates or cause other read errors.
- An error-free disc will open much faster than an error-ridden one. If a particular disc is much slower than other similar discs, consider this a warning and copy it as soon as possible to another disc.