When was that?: Maintaining or changing ‘created’ and ‘last modified’ dates

Sarah has recently been testing scenarios to investigate the question of changes in file ‘date created’ and ‘last modified’ metadata. When building training, it’s always best to test out what your advice before giving it and below is the result of Sarah’s research with helpful screenshots.


Before doing some training that involved teaching better recordkeeping habits to staff, I ran some tests to be sure that I was giving the right advice when it came to created and last modified dates. I am often told by people in the field that these dates are always subject to change—but are they really? I knew I would tell staff to put created dates in file names or in document headers in order to retain that valuable information, but could the file maintain the correct embedded date anyways?  I set out to test a number of scenarios on both my Mac OS X laptop and Windows desktop.

Scenario 1: Downloading from cloud storage (Google Drive)

This was an ALL DATES change for both Mac OS X and Windows.

Scenario 2: Uploading to cloud storage (Google Drive)

Once again this was an ALL DATES change for both systems.

Note: I trialled this a second time with the Google Drive for PC application and in OS X and found that created and last modified dates do not change when the file is uploaded or downloaded the Google Drive folder on the PC. However, when in Google Drive via the website, the created date is different (the date/time of upload), though the ‘file info’ will confirm the date has not changed. Just to complicate things.

Scenario 3: Transfer from a USB

Mac OS X had no change to the dates. Windows showed an altered created date, but maintained the original last modified date.

Scenario 4: Transfer to a USB

Once again there was no change of a dates in the Mac OS X. Windows showed an altered created date, but maintained the original last modified date.

Note: I looked into scenarios 3 and 4 for Windows a bit further and saw that Robocopy is an option as a command prompt that will allow directories to be copied across and maintains those date attributes. I copied a ‘TEST’ folder containing the file from the Windows computer to the USB, and back again. It did what was promised and there were no changes to either dates in the file. It is a bit annoying that an extra step is required (that many people would find technically challenging and therefore avoid).

Scenario 5: Moving between folders

No change across either systems. This was a relief for me considering how often I move files around my directories.

Conclusions

When in doubt (and you should always be in doubt), test the scenario. Even when I tested these scenarios three of four times, it did not always come out with the same result. That alone should make one cautious. I still stick to putting created date in the file name and in the document itself (where possible), but it doesn’t meant I always receive documents that way.

Creating a zip of files/folders before transfer is one method of preserving dates, but I had some weird issues trying to unzip the file in cloud storage that took a few tries before the dates remained preserved. It is also possible to use Quickhash for transferring files unchanged (and it generates a checksum).

I ignored the last accessed date during testing, because it was too easy to accidentally double-click a file and change it (as you can see happened to my Windows 7 test version).

Has anyone tested any other scenarios to assess when file dates are altered? Does anyone have methods for transferring files without causing any change to dates?

An approach to selecting case studies

Cambridge Policy & Planning Fellow, Somaya, writes about a case study approach developed by the Cambridge DPOC Fellows for CUL. Somaya’s first blog post about the case studies looks at the selection methodology the Cambridge DPOC fellows used to choose their final case studies.


Physical format digital carriers. Photo: Somaya Langley

Background & approach

Cambridge University Library (CUL) has moved to a ‘case study’ approach to the project. The case studies will provide an evidence-based foundation for writing a policy and strategy, developing a training programme and writing technical requirements within the time constraints of the project.The case studies we choose for the DPOC project will enable us to test hands-on day-to-day tasks necessary for working with digital collection materials at CUL. They also need to be representative of our existing collections and future acquisitions, our Collection Development Policy FrameworkStrategic Plan,  our current and future audiences, while considering the ‘preservation risk’ of the materials.

Classes of material

Based on the digital collections surveying work I’ve been doing, our digital collections fall into seven different ‘classes’:

  1. Unpublished born-digital materials – personal and corporate papers, digital archives of significant individuals or institutions
  2. Born-digital university archives – selected records of the University of Cambridge
  3. Research outputs – research data and publications (including compliance)
  4. Published born-digital materials – physical format carriers (optical media), eBooks, web archives, archival and access copies of electronic subscription services, etc.
  5. Digitised image materials – 2D photography (and 3D imaging)
  6. Digital (and analogue) audiovisual materials – moving image (film and video) and sound recordings
  7. In-house created content – photography and videography of events, lectures, photos of conservation treatments, etc.

Proposed case studies

Approximately 40 potential case studies suggested by CUL and Affiliated Library staff were considered. These proposed case studies were selected from digital materials in our existing collections, current acquisition offers, and requests for assistance with digital collection materials, from across Cambridge University. Each proposed case study would allow us to trial different tools (and digital preservation systems), approaches, workflow stages, and represent different ‘classes’ of material.

Digital lifecycle stages

The selected stages are based on a draft Digital Stewardship End-to-End Workflow I am developing. The workflow includes approximately a dozen different stages. It is based on the Digital Curation Centre’s Curation Lifecycle Model, and is also aligned with the Digital POWRR (Preserving Digital Objects with Restricted Resources) Tool Evaluation Grid.

There are also additional essential concerns, including:

  • data security
  • integration (with CUL systems and processes)
  • preservation risk
  • remove and/or delete
  • reporting
  • resources and resourcing
  • system configuration

Selected stages for Cambridge’s case studies

Dave, Lee and I discussed the stages and cut it down to the bare-minimum required to test out various tasks as part of the case studies. These stages include:

  1. Appraise and Select
  2. Acquire / Transfer
  3. Pre-Ingest (including Preconditioning and Quality Assurance)
  4. Ingest (including Generate Submission Information Package)
  5. Preservation Actions (sub-component of Preserve)
  6. Access and Delivery
  7. Integration (with Library systems and processes) and Reporting

Case study selection

In order to produce a shortlist, I needed to work out a parameter best suited in order to rank the proposed case studies from a digital preservation perspective. The initial parameter we decided on was complexity. Did the proposed case study provide enough technical challenges to fully test out what we needed to research?

We also took into account a Streams Matrix (still in development) that outlines different tasks taken at each of the at each of the selected digital life cycle stages. This would ensure different variations of activities were factored in at each stage.

We revisited the case studies once in ranked order and reviewed them, taking into account additional parameters. The additional parameters included:

  • Frequency and/or volume – how much of this type of material do we have/are we likely to acquire (i.e. is this a type of task that would need to be carried out often)?
  • Significance – how significant is the collection in question?
  • Urgency – does this case study fit within strategic priorities such as the current Cambridge University Library Strategic Plan and Collection Development Policy Framework etc.?
  • Uniqueness – is the case study unique and would it be of interest to our users (e.g. the digital preservation field, Cambridge University researchers)?
  • Value to our users and/or stakeholders – is this of value to our current and future users, researchers and/or stakeholders?

This produced a shortlist of eight case studies. We concluded that each provided different long-term digital preservation issues and were experiencing considerable degrees of ‘preservation risk’.

Conclusion

This was a challenging and time-consuming approach, however it ensures fairness in the selection process. The case studies will enable us to have tangible evidence in which to ground the work of the rest of the project. The Cambridge University Library Polonsky Digital Preservation Project Board have agreed that we will undertake three case studies, including a digitisation case study, a born-digital case study and one more – the details of which are still being discussed. Stay tuned for more updates.