Digital Preservation
Preservation Processing of Physical Format Digital Publications (PFDPs)
Digital publications acquired by the Library through deposit or purchase may be selected for preservation in accordance with the preservation selection guidelines.
The Digital Preservation section assesses each publication for its hardware and software requirements, as well as any additional information required to run it, such as special installation instructions or passwords. Two lists are maintained:
- a data sheet for recording publication and disc details, system requirements, installation and use notes for each publication.
- an overall list of hardware and software required to support the collection, including versions, and indicating preferred terms to be used consistently in the data sheet. This list is updated when new hardware and software requirements, versions or term variants are encountered during processing.
Additionally, the contents of floppy disc publications are currently transferred to a more stable medium (CD-R). Further work will include developing procedures for the general transfer of physical format publications to digital mass storage.
Assessment of physical format digital publications for preservation
The procedure for assessing each publication is as follows:
- Floppy discs are made write-protected to prevent alteration during processing.
- All discs (floppy discs, CDs, DVDs) are scanned for viruses using up-to-date virus detection software.
- Using a file management utility, a full directory and file listing of each disc is created. This step gains basic file level information about the publications and also aids processing, allowing the range of files and subdirectories to be easily seen.
- The system requirements described in the catalogue for the publication are checked. The disc, packaging and any accompanying documentation are also checked for further statements of requirements.
- The publication is run or installed to check that it is functional. Any further hardware, software or installation requirements are determined from this check and from inspection of the publication files.
- Any additional system requirements obtained from the packaging, documentation, file listing and the installation process are described in the data sheet entry for the publication, including special instructions for installation and any passwords required.
- The overall list of hardware and software requirements is updated if any system requirements, including versions, are encountered which have not previously been listed.
- If the publication is on CD, the discs are returned to the stack for storage. If the publication is on floppy disc, the publication is copied to a more stable medium such as CD-R, according to the next section.
Preservation copying of floppy discs
Floppy disc publications are copied for preservation according to the following steps:
- A new directory is created on a secure drive and is named according to identifier for the publication. Subdirectories are created for each disc of the publication to be copied.
- Disc contents are copied into the corresponding directory on the destination drive.
- Using a file comparison utility, the copies are compared to the original discs to ensure that they are identical at the bit level. If this test fails, files are recopied until successful.
- Copied publication files are set to 'read-only' to simulate the state of being on CD-R.
- The copied publication is installed or run from the destination drive, to check that it will work in the copied, 'read-only' state. If this test fails, further checks are made to determine whether the publication cannot be run as 'read-only' or whether additional steps are needed to run from a copy.
- After this check is complete, the 'read-only' setting is unset.
- For each publication a 'read me' text file is created in the publication directory. The ‘read me’ file is used to record publication and disc details, system requirements, instructions for installation and use, and any preservation actions taken, including copying.
- When a sufficient number of publications have been accumulated they are written to each of two CD-Rs.
- The files on both CD-Rs are checked at the bit level against the drive copies using a file comparison utility. If this test fails, CD-Rs are re-written.
- Both CD-Rs are error tested. If this test fails, CD-Rs are re-written.
- As a further check, around ten percent of the publications on the CD-Rs are run or installed.
- One CD-R is stored as a master copy. The other is made available for access.
- Original floppy discs are sealed in individual bags with a notice redirecting users to the CD-R access copy, and discs are returned to secure storage in the stack.
