A typical week as a digital archivist?

Sometimes (admittedly not very often) I'm asked what I actually do all day. So at the end of a busy week being a digital archivist I've decided to blog about what I've been up to.

Monday

Today I had a couple of meetings. One specifically to talk about digital preservation of electronic theses submissions. I've also had a work experience placement in this week so have set up a metadata creation task which he has been busy working on.

When I had a spare moment I did a little more testing work on the EAD harvesting feature the University of York is jointly sponsoring Artefactual Systems to develop in AtoM. Testing this feature from my perspective involves logging into the test site that Artefactual has created for us and tweaking some of the archival descriptions. Once those descriptions are saved, I can take a peek at the job scheduler and make sure that new EAD files are being created behind the scenes for the Archives Hub to attempt to harvest at a later date.

This piece of development work has been going on for a few months now and communications have been technically quite complex so I'm also trying to ensure all the organisations involved are happy with what has been achieved and will be arranging a virtual meeting so we can all get together and talk through any remaining issues.

I was slightly surprised today to have a couple of requests to talk to the media. This has sprung from the news that the Queen's Speech will be delayed. One of the reasons for the delay relates to the fact that the speech has to be written on goat's skin parchment, which takes a few days to dry. I had previously been interviewed for a article entitled Why is the UK still printing its laws on vellum? and am now mistaken for someone who knows about vellum. I explained to potential interviewers that this is not my specialist subject!

Tuesday

In the morning I went to visit a researcher at the University of York. I wanted to talk to him about how he uses Google Drive in relation to his research. This is a really interesting topic to me right now as I consider how best we might be able to preserve current research datasets. Seeing how exactly Google Drive is used and what features the researcher considers to be significant (and necessary for reuse) is really helpful when thinking about a suitable approach to this problem. I sometimes think I work a little bit too much in my own echo chamber, so getting out and hearing different perspectives is incredibly valuable.

Later that afternoon I had an unexpected meeting with one of our depositors (well, there were two of them actually). I've not met them before but have been working with their data for a little while. In our brief meeting it was really interesting to chat and see the data from a fresh perspective. I was able to reunite them with some digital files that they had created in the mid 1980's, had saved on to floppy disk and had not been able to access for a long time.

Digital preservation can be quite a behind the scenes sort of job - we always give a nod to the reason why we do what we do (ie: we preserve for future reuse), but actually seeing the results of that work unfold in front of your eyes is genuinely rewarding. I had rescued something from the jaws of digital obsolescence so it could now be reused and revitalised!

At the end of the day I presented a joint webinar for the Open Preservation Foundation called 'PRONOM in practice'. Alongside David Clipsham (The National Archives) and Justin Simpson (Artefactual Systems), I talked about my own experiences with PRONOM, particularly relating to file signature creation, and ending with a call to arms "Do try this at home!". It would be great if more of the community could get involved!

I was really pleased that the webinar platform worked OK for me this time round (always a bit stressful when it doesn't) and that I got to use the yellow highlighter pen on my slides.

In my spare moments (which were few and far between), I put together a powerpoint presentation for the following day...

Wednesday

I spent the day at the British Library in Boston Spa. I'd been invited to speak at a training event they regularly hold for members of staff who want to find out a bit more about digital preservation and the work of the team.

I was asked specifically to talk through some of the challenges and issues that I face in my work. I found this pretty easy - there are lots of challenges - and I eventually realised I had too many slides so had to cut it short! I suppose that is better than not having enough to say!

Visiting Boston Spa meant that I could also chat to the team over lunch and visit their lab. They had a very impressive range of old computers and were able to give me a demonstration of Kryoflux (which I've never seen in action before) and talk a little about emulation. This was a good warm up for the DPC event about emulation I'm attending next week: Halcyon On and On: Emulating to Preserve.

Still left on my to do list from my trip is to download Teracopy. I currently use Foldermatch for checking that files I have copied have remained unchanged. From the quick demo I saw at the British Library I think that Teracopy would be a more simple one step solution. I need to have a play with this and then think about incorporating it into the digital ingest workflow.

Sharing information and collaborating with others working in the digital preservation field really is directly beneficial to the day to day work that we do!

Thursday

Back in the office today and a much quieter day.

I extracted some reports from our AtoM catalogue for a colleague and did a bit of work with our test version of Research Data York. I also met with another colleague to talk about storing and providing access to digitised images.

In the afternoon I wrote another powerpoint presentation, this time for a forthcoming DPC event: From Planning to Deployment: Digital Preservation and Organizational Change.

I'm going to be talking about our experiences of moving our Research Data York application from proof of concept to production. We are not yet in production and some of the reasons why will be explored in the presentation! Again I was asked to talk about barriers and challenges and again, this brief is fairly easy to fit! The event itself is over a week away so this is unprecedentedly well organised. Long may it continue!

Friday

On Fridays I try to catch up on the week just gone and plan for the week ahead as well as reading the relevant blogs that have appeared over the week. It is also a good chance to catch up with some admin tasks and emails.

Lunch time reading today was provided by William Kilbride's latest blog post. Some of it went over my head but the final messages around value and reuse and the need to "do more with less" rang very true.

Sometimes I even blog myself - as I am today!




Was this a typical week - perhaps not, but in this job there is probably no such thing! Every week brings new ideas, challenges and surprises!

I would say the only real constant is that I've always got lots of things to keep me busy.

Jenny Mitcham, Digital Archivist

What have we got in our digital archive?

Do other digital archivists find that the work of a digital archivist rarely involves doing hands on stuff with digital archives? When you have to think about establishing your infrastructure, writing policies and plans and attending meetings it leaves little time for activities at the coal face. This makes it all the more satisfying when we do actually get the opportunity to work with our digital holdings.

In the past I've called for more open sharing of profiles of digital archive collections but I am aware that I had not yet done this for the contents of our born digital collections here at the Borthwick Institute for Archives. So here I try to redress that gap.

I ran DROID (v 6.1.5, signature file v 88, container signature 20160927) over the deposited files in our digital archive and have spent a couple of days crunching the results. Note that this just covers the original files as they have been given to us. It does not include administrative files that I have added, or dissemination or preservation versions of files that have subsequently been created.

I was keen to see:

• How many files could be automatically identified by DROID
• What the current distribution of file formats looks like
• Which collections contain the most unidentified files

...and also use these results to:

• Inform future preservation planning and priorities
• Feed further information to the PRONOM team at The National Archives
• Get us to Level 2 of the NDSA Levels of Digital Preservation which asks for "an inventory of file formats in use" and which until now I haven't been collating!

Digital data has been deposited with us since before I started at the Borthwick in 2012 and continues to be deposited with us today. We do not have huge quantities of digital archives here as yet (about 100GB) and digital deposits are still the exception rather than the norm. We will be looking to chase digital archives more proactively once we have a Archivematica in place and appropriate workflows established.

Last modified dates (as recorded by DROID) appear to range from 1984 to 2017 with a peak at 2008. This distribution is illustrated below. Note however, that this data is not always to be trusted (that could be another whole blog post in itself...). One thing that it is fair to say though is that the archive stretches back right to the early days of personal computers and up to the present day.

Last modified dates on files in the Borthwick digital archive

Here are some of the findings of this profiling exercise:

Summary statistics

• Droid reported that 10005 individual files were present
• 9431 (94%) of the files were given a file format identification by Droid. This is a really good result ...or at least it seems it in comparison to my previous data profiling efforts which have focused on research data. This result is also comparable with those found within other digital archives, for example 90% at Bentley Historical Library, 96% at Norfolk Record Office and 98% at Hull University Archives
• 9326 (99%) of those files that were identified were given just one possible identification. 1 file was given 2 different identifications (an xlsx file) and 104 files (with a .DOC extension) were given 8 identifications. In all these cases of multiple identifications, identification was done by file extension rather than signature - which perhaps explains the uncertainty

Files that were identified

• Of the 9431 files that were identified:
• 6441 (68%) were identified by signature (which suggests a fairly accurate identification - if a file is identified by signature it means that Droid has looked inside the file and seen something that it recognises. Last year I was inducted into the magic ways this happens - see My First File Format Signature!)
• 2546 (27%) were identified by container (which again suggests a high level of accuracy). The vast majority of these were Microsoft Office files 
• 444 (5%) were identified by extension alone (which implies a less accurate identification)

• Only 86 (1%) of the identified files had a file extension mismatch - this means that the file extension was not what you would expect given the identification by signature. There are all sorts of different examples here including:
• files with a tmp or dot extension which are identified as Microsoft Word
• files with a doc extension which are identified as Rich Text Format
• files with an hmt extension identifying as JPEG files
• and as in my previous research data example, a bunch of Extensible Markup Language files which had extensions other than XML

So perhaps these are things I'll look into in a bit more detail if I have time in the future.

• 90 different file formats were identified within this collection of data

• Of the identified files 1764 (19%) were identified as Microsoft Word Document 97-2003. This was followed very closely by JPEG File Interchange Format version 1.01 with 1675 (18%) occurrences. The top 10 identified files are illustrated below:

• This top 10 is in many ways comparable to other similar profiles that have been published recently from Bentley Historical Library, Hull University Archive and Norfolk Records Office with high occurrences of Microsoft Word, PDF and JPEG images. In contrast. what it is not so common in this profile are HTML files and GIF image files - these only just make it into the top 50. 

• Also notable in our top ten are the Sibelius files which haven't appeared in other recently published profiles. Sibelius is musical notation software and these files appear frequently in one of our archives.

Files that weren't identified

• Of the 574 files that weren't identified by DROID, 125 different file extensions were represented. For most of these there was just a single example of each.

• 160 (28%) of the unidentified files had no file extension at all. Perhaps not surprisingly it is the earlier files in our born digital collection (files from the mid 80's), that are most likely to fall into this category. These were created at a time when operating systems seemed to be a little less rigorous about enforcing the use of file extensions! Approximately 80 of these files are believed to be WordStar 4.0 (PUID:  x-fmt/260) which DROID would only be able to recognise by file extension. Of course if no extension is included. DROID has little chance of being able to identify them!

• The most common file extensions of those files that weren't identified are visible in the graph below. I need to do some more investigation into these but most come from 2 of our archives that relate to electronic music composition:

I'm really pleased to see that the vast majority of the files that we hold can be identified using current tools. This is a much better result than for our research data. Obviously there is still room for improvement so I hope to find some time to do further investigations and provide information to help extend PRONOM.

Other follow on work involves looking at system files that have been highlighted in this exercise. See for example the AppleDouble Resource Fork files that appear in the top ten identified formats. Also appearing quite high up (at number 12) were Thumbs.db files but perhaps that is the topic of another blog post. In the meantime I'd be really interested to hear from anyone who thinks that system files such as these should be retained.

Jenny Mitcham, Digital Archivist

Filling the Digital Preservation Gap - final report available

Today we have published our third and final Filling the Digital Preservation Gap report.

The report can be accessed from Figshare: https://dx.doi.org/10.6084/m9.figshare.4040787

This report details work the team at the Universities of York and Hull have been carrying out over the last six months (from March to September 2016) during phase 3 of the project.

The first section of the report focuses on our implementation work. It describes how each institution has established a proof of concept implementation of Archivematica integrated with other systems used for research data management. As well as describing how these implementations work it also discusses future priorities and lessons learned.

The second section of the report looks in more detail at the file format problem for research data. It discusses DROID profiling work that has been carried out over the course of the project (both for research data and other data types) and signature development to increase the number of research data signatures in the PRONOM registry. In recognition of the fact that this is an issue that can only be solved as a community, it also includes recommendations for a variety of different stakeholder groups.

The final section of the report details the outreach work that we have carried out over the course of this final phase of the project. It has been a real pleasure to have been given an opportunity to speak about our work at so many different events and to such a variety of different groups over the last few months!

The last of this run of events in our calendars is the final Jisc Research Data Spring showcase in Birmingham tomorrow (20th October). I hope to see you there!




Jenny Mitcham, Digital Archivist

File format identification at Norfolk Record Office

This is a guest post from Pawel Jaskulski who has recently completed a Transforming Archives traineeship at Norfolk Record Office (NRO). As part of his work at Norfolk and in response to a question I posed in a previous blog post ("Is identification of 37% of files a particularly bad result?") he profiled their digital holdings using DROID and has written up his findings. Coming from a local authority context, his results provide an interesting comparison with other profiles that have emerged from both the Hull History Centre and the Bentley Historical Library and again help to demonstrate that the figure of 37% identified files for my test research dataset is unusual.

King's Lynn's borough archives are cared for jointly by the Borough Council and the Norfolk Record Office

Profiling Digital Records with DROID

With any local authority archive there is an assumption that the accession deposited might be literally anything. What it means in 'digital terms' is that it is impossible to predict what sort of data might be coming in in the future. That is the reason why NRO have been actively involved in developing their digital preservation strategy, aiming at achieving capability so as to be able to choose digital records over their paper-based equivalents (hard copies/printouts).

The archive service has been receiving digital records accessions since the late 1990's. The majority of digitally born archives came in as hybrid accessions from local schools that were being closed down. For many records there were no paper equivalents. Among other deposits containing digital records are architectural surveys, archives of private individuals and local organisations (for example Parish Council meetings minutes).

The archive service have been using DROID as part of their digital records archival processing procedure as it connects to the most comprehensive and continuously updated file formats registry PRONOM. Archivematica, an ingest system that uses the PRONOM registry, is currently being introduced at NRO. It contains other file format identification tools like FIDO or Siegfried (which both use PRONOM identifiers).

The results of DROID survey were as follows:

With the latest signature file (v.86) out of 49,117 files identification was successful for 96.46%.

DROID identified 107 various file formats. The ten most recurring file formats were:

Classification	File Format Name	Versions	PUIDS
Image (Raster)	JPEG File Interchange Format	1.01, 1.02	fmt/43, fmt/44
Image (Raster)	Exchangeable Image File Format (Compressed)	2.1, 2.2	x-fmt/390, x-fmt/391
Image (Raster)	Windows Bitmap	3	fmt/116
Text (Mark-up)	Hypertext Markup Language	4	fmt/96, fmt/99
Word Processor	Microsoft Word Document	97-2003	fmt/40
Image (Raster)	Tagged Image File Format		fmt/353
Email	Microsoft Outlook Email Message	97-2003	x-fmt/430
Miscellaneous	AppleDouble Resource Fork		fmt/503
Image (Raster)	Graphics Interchange Format	89a	fmt/4
Image (Raster)	Exchangeable Image File Format (Compressed)	2.2.1	fmt/645

Identification method breakdown:

• 83.31% was identified by signature
• 14.95% by container
• 1.73% by Extension 

458 files had their extensions mismatched - that amounts to less than one per cent (0.97%). These were a variety of common raster image file formats (JPEG, PNG, TIFF) word processor (Microsoft Word Document, ClarisWorks Word Processor) and desktop publishing (Adobe Illustrator, Adobe InDesign Document, Quark Xpress Data File).

Among 3.54% of unidentified files there were 160 different unknown file extensions. Top five were:

• .cmp
• .mov
• .info
• .eml
• .mdb

Two files returned more than 1 identification:

A spreadsheet file with .xls extension (last modified date 2006-12-17) had 3 possible file format matches:

• fmt/175 Microsoft Excel for Macintosh 2001
• fmt/176 Microsoft Excel for Macintosh 2002
• fmt/177 Microsoft Excel for Macintosh 2004

And an image file with extension .bmp (last modified date 2007-02-06) received 2 file format matches

• fmt/116 Windows Bitmap 3
• fmt/625 Apple Disk Copy Image 4.2

After closer inspection the actual file was a bitmap image file and PUID fmt/116 was the correct one.

Understanding the Results

DROID offers very useful classification of file formats and puts all results into categories, which enables an overview of the digital collection. It is easy to understand what sort of digital content is predominantly included within the digitally born accession/archive/collection. It uses classification system that assigns file formats to broader groups like: Audio, Word Processor, Page Description, Aggregate etc. These help enormously in having a grasp on the variety of digital records. For example it was interesting to discover that over half of our digitally born archives are in various raster image file formats.

Files profiled at Norfolk Record Office as classified by DROID

I am of course also interested in the levels of risk associated with particular formats so have started to work on an additional classification for the data, creating further categories that can help with preservation planning. This would help demonstrate where preservation efforts should be focused in the future.

Jenny Mitcham, Digital Archivist

My first file format signature

As part of Filling the Digital Preservation Gap we've been doing a lot of talking about the importance of accurate file format identification and the challenges of doing so for research data.

Now we are thinking about how we can help solve the problem.

As promised in a post last month, I wanted to have a go at file format signature creation for PRONOM to see whether it is something that an average digital archivist could get their head around. Never before had I created my own signature. In the past I had considered this to be work that only technical people could carry out and it would be foolhardy to attempt it myself.

However, given the extent of the file formats identification challenge for research data wouldn't it be great if the community could engage more directly? Also, shouldn't file signature development be something every digital archivist should have a good understanding of?

Encouraged by Ross Spencer's blog post Five Star File Format Signature Development and a meeting with the PRONOM team at The National Archives in which the tricks and challenges of signature creation were explained, I decided to give it a go.

Where to begin?

• First I read TNA's How to research and develop signatures for file format identification. This is an accessible and readable guide which tells you how to get started with signature development - from gathering samples, doing internet research on the format and using a Hex Editor to spot patterns. You don't need to be very technically minded to get your head around it.
• Then I downloaded and installed a Hex editor. Though it is possible to view files as hexadecimal within Quick View Plus, I followed TNA's advice and used HxD Hex Editor as this allows you to compare files thus partially automating the process of spotting sequences.
• Once I'd spotted a pattern which could be used to create a signature, I planned to use PRONOM's Signature Development Utility to create it. 
• Once the signature is created I'm told it is possible to test this using DROID. Within DROID, go to Tools... Install signature file and replace the current signature with your new one (but remember to put it back again once you are done otherwise you may wonder why DROID isn't working properly!). Run this over your directory of sample files to see if they are all correctly identified using the signature you have developed. 

I decided start off with something that had been at the back of my mind for a while...those Wordstar 4.0 files from the Marks and Gran archive that I blogged about some time ago and had struggled to identify. When I wrote that post three years ago, Wordstar 4.0 files were not represented in PRONOM. They have more recently been added and the files can be identified but this is by extension only - not the more accurate file signature. I thought it would be fun to try and create a file signature for them.

I was very wrong.

My attempts to see a pattern within the files using the Hex Editor were unsuccessful. I decided to send the sample files to the experts at TNA to see if I was missing something. It was quickly confirmed that this was a rather awkward file type and not one that lent itself well to being automatically identified. Disappointing but at least it confirmed that my own investigations were not lacking.

For my next attempt I decided to tackle some of the unidentified research data that I had highlighted in my previous post Research data - what does it *really* look like?

I looked through the top ten most frequent unidentified file extensions in my sample and started to dig out the files themselves and assess whether they were a good candidate for me to work on. Ross Spencer suggests that PRONOM lends itself best to the creation of signatures for binary formats so this is what I wanted to focus on. No point in trying to make it hard for myself!

• dat - 286
• crl - 259
• sd - 246
• jdf - 130 (a signature for these JEOL NMR Spectroscopy files is now available)
• out - 50
• mrc - 47
• inp - 46
• xyz - 37
• prefs - 32
• spa - 32

Unfortunately, looking through the list (and digging out some samples) I discovered that many of these are ASCII formats rather than binary. It is possible to create signatures to identify ASCII files but it can be challenging (involving quite complex regular expressions) and not a great place for a first timer to start. I certainly did not want to start to tackle the confusing landscape of .dat files either!

After a little bit of investigation I discovered that the .spa files were something I could work with. I knew nothing about this format but found the relevant files and started doing some internet research looking for more information and perhaps some additional samples. I soon discovered they were one of many formats for optical spectroscopy and are known as Thermo Fisher’s OMNIC file format or Thermo Scientific OMNIC or Nicolet/Thermo OMNIC.

Looking at some of the files using a Hex Editor it was immediately apparent that there was a consistent pattern of bytes at the start of each file. A string which read 'Spectral Data File' which was represented by 53 70 65 63 74 72 61 6C 20 44 61 74 61 20 46 69 6C 65 in hexadecimal. Note that I actually thought the pattern was longer but advice received from the PRONOM team suggested that it was better to cut it down.

I also looked at the end of each file and at first sight there appeared to be consistency here too with each file ending with the same few bytes. This hypothesis was blown out of the water when I looked at a sample file that I had discovered online which did not display this pattern (but luckily did have the same bytes at the start of the file).

This is why it is so important to have sample data that comes from more than one source. A set of files from a single researcher may have misleading patterns that have occurred just because of the consistent way in which they work, rather than this being a true feature of the format itself.

So, once I'd looked at all 33 files and had convinced myself the hypothesis was solid, I went to the online signature development tool provided by The National Archives and created my signature.

PRONOM signature development tool

This was relatively easy to use but there were areas where more guidance was needed (so questions were fired off to the PRONOM team and a speedy response was received). I'm hoping that in the future there will be more documentation to help guide the completion of this form - so that people know how best to name the signature, where to find a definitive list of Mimetypes (this is the list they suggested I looked at), and what the Version field should contain (it is for the version of the file format if this is apparent/relevant - not the version of the signature you are creating).

Once I was done, I clicked on the 'Save Signature File' button and I was presented with the finished XML file:

Ta daaaaa!

I briefly admired my handiwork before sending it off to The National Archives for feedback.*

How long did it take me to do all of this? I would say one full day is a fair estimate (that would include reading the guidance, downloading the Hex Editor and a few false starts as I tried to find a format that I thought I could handle). The next signature would be much quicker.

The biggest challenges:

1. It took me a while to find a binary format that I could work with. Much of the research data we hold appears to be ASCII formats ....which has benefits from a digital preservation perspective, but wasn't what I was looking for with regard to this exercise
2. I did not really understand the file format I was working with. I am not a chemist. I have never heard of the .spa format. I struggle to even say 'Spectroscopy' let alone understand it. When I started to research it online I found the results quite confusing. If I knew more about the format in the first place it would have made life much easier. 
3. There are limitations with the metadata we get from researchers when they deposit data with Research Data York. Reading the brief descriptions of the dataset that are provided did not really help me work out what the individual files are or what software and hardware was used to create them.
4. I could not locate the file format specification online - I think next time I try this I may approach the software vendor direct and ask them for help. 
5. Available documentation for creating and testing signatures could be enhanced. I had several questions as I went along and these were answered promptly by the PRONOM team, but if the information was all online then this would certainly help other newbies.

Despite the challenges this exercise has been both enjoyable and useful. The thing I like about being a digital archivist is being able to get hands on with the data and solve problems. Over the last few years I've done very little of this type of work so it was great to get stuck in. On top of the obvious benefit that after the next signature release these .spa files will now be recognised by DROID and other PRONOM-based file identification tools, I have also increased my knowledge and understanding of the process and this is a positive result.

I would definitely encourage other digital archivists, repository managers and research data managers to try this out for themselves.



* Feedback from the PRONOM team was positive. With a couple of modifications they were happy to include the signature in the next PRONOM signature release

Jenny Mitcham, Digital Archivist

Research data is different

This is a guest post from Simon Wilson who has been profiling the born-digital data at the Hull History Centre to provide another point of comparison with the research data at York reported on in this blog back in May.

Inspired by Jen’s blog Research data - what does it *really* look like? about the profile of the  research data at York and the responses it generated including that from the Bentley Historical Library, I decided to take a look at some of the born-digital archives we have at Hull. This data is not research data from academics, it is data that has been donated to or deposited with the Hull History Centre and it comes from a variety of different sources.

Whilst I had previously created a DROID report for each distinct accession I have never really looked into the detail, so for each accession I did the following;

1. Run the DROID software and export the results into csv format with one row per file 
2. Open the file in MS Excel and copy the data to a second tab for the subsequent actions
3. Sort the data by Type field into A-Z order and then delete all of the records relating to folders 
4. Sort the data on the PUID field into A-Z order
5. For large datasets highlight the data and then select the subtotal tool and use it to count each time the PUID field changes and record the sub-total
6. Once the subtotal tool has completed its calculations, select the entire dataset and select Hide Detail (adjacent to Subtotal in the Outline tools box) to leave you with just a row for each distinct PUID and the total count value

I then created a simple spreadsheet with a column for each distinct accession and added a row for each unique PUID, copying the MIME type, software and version details from the DROID report results.  I also noted the number of files that were not identified. There may be quicker ways to get the same results and I would love to hear other suggestions or shortcuts.

After having completed this for 24 accessions - totalling 270,867 files, what have I discovered?

• An impressive 97.96% of files were identified by DROID (compared with only 37% in Jen's smaller sample of research data)
• So far 228 different PUIDs have been identified (compared with 34 formats in Jen’s sample)
• The most common format is fmt/40 (MS Word 97-2003) with 120,595 files (44.5%). See the top ten identified formats in the table below...

File format (version)	Total No files	% of total identified files
Microsoft Word Document (97-2003)	120,595	44.52%
Microsoft Word for Windows (2007 onwards)	15,261	5.63%
Microsoft Excel 97 Workbook	13,750	5.08%
Graphics Interchange Format	11,240	4.15%
Acrobat PDF 1.4 - Portable Document Format	8458	3.12%
JPEG File Interchange Format (1.01)	7357	2.72%
Microsoft Word Document (6.0 / 95)	6656	2.46%
Acrobat PDF 1.3 - Portable Document Format	6462	2.39%
JPEG File Interchange Format (1.02)	4947	1.83%
Hypertext Markup Language (v4)	4512	1.67%

I can now quickly look-up whether an individual archive has a particular file type, and see how frequently it occurs.  Once I have processed a few more accessions it may be possible to create a "profile" for an individual literary collection or a small business and use this to inform discussions with depositors.  I can also start to look at the identified file formats and determine whether there is a strategy in place to migrate that format. Where this isn’t the case, knowing the number and frequency of the format amongst the collections will allow me to prioritise my efforts.  I will also look to aggregate the data – for example merging all of the different versions of Adobe Acrobat or MS Word.

I haven’t forgotten the 5520 unidentified files. By noting the PRONOM signature file number used to profile each archive, it is easy to repeat the process with a later signature file.  This could validate the previous results or enable previously unidentified files to be identified (particularly if I use the results of this exercise to feed information back to the PRONOM team). Knowing which accessions have the largest number of unidentified files will allow me to focus my effort as appropriate.

Whilst this has certainly been a useful exercise in its own right, it is also interesting to note the similarities between this the and the born-digital archives profile published by the Bentley Historical Library and the contrast with the research data profile Jen reported on.

The top ten identified formats from Hull and Bentley are quite similar. Both have a good success rate for identifying file formats with 90% identified at Bentley and 98% at Hull. Though the formats do not appear in the same order in the top ten, they do contain similar types of file (MS Word, PDF, JPEGs, GIFs and HTML).

In contrast, only 37% of files were identified in York's research data sample and the top ten file formats that were identified look very different. The only area of overlap being MS Excel files which appear high up in the York research dataset as well as being in the top ten for the Hull History Centre.

Research data is different.



Jenny Mitcham, Digital Archivist

New research data file formats now available in PRONOM

Like all good digital archivists I am interested in file formats and how we can use tools to automatically identify them. This is primarily so that when we package our digital archives up for long term preservation we can do so with a level of knowledge about how we might go about preserving and providing access to them in the future. This information is key whether migration or emulation is the preservation or access strategy of choice (or indeed a combination of both).

It has been really valuable to have some time and money as part of our "Filling the Digital Preservation Gap" project to be able to investigate issues around the identification of research data file formats and very pleasing to see the latest PRONOM signature release on 29th June which includes a couple of research data formats that we have sponsored as part of our project work.

I sent a batch of sample files off to the team who look after PRONOM at The National Archives (TNA) with a bit of contextual information about the formats and software/hardware that creates them (that I had uncovered after a bit of research on Google). TNA did the rest of the hard work and these new signatures are now available for all to use.

The formats in question are:

• Gaussian input files - These are created for an application called Gaussian which is used by many researchers in the Chemistry department here in York. In a previous project update you can see that Gaussian was listed in the top 10 research software applications in use at the University of York. These files are essentially just ascii text files containing instructions for Gaussian and they can have a range of file extensions (though the samples I submitted were all .gjf). Though there is a recommended format or syntax for these instructions, there also appears to be flexibility in how these can be applied. Consequently this was a slightly challenging signature for TNA to work on and it would be useful if other institutions that have Gaussian input files could help test this signature and feedback to TNA if there are any problems or issues. In instances like this being able to develop against a range of sample files created at different times in different institutions by different researchers would help.
• JEOL NMR Spectroscopy files - These are data files produced by JEOL's Nuclear Magnetic Resonance Spectrometers. These facilities at the University of York are clearly well used as data of this type was well represented in an initial assessment of the data that I reported on in a blog post last month (130 .jdf files were present in the sample of 3752 files). As these files are created by a piece of hardware in a very standard way, I am told that signature developers at TNA were able to create a signature without too many problems.

Further formats submitted from our project will appear in PRONOM within the next couple of months.

The project team are also interested in finding out how easy it is to create our own file format signatures. This is an alternative option for those who want to contribute but not something we have attempted before. Watch this space to find out how we get on!



Jenny Mitcham, Digital Archivist

Research data - what does it *really* look like?

Work continues on our Filling the Digital Preservation Gap project and I thought it was about time we updated you on some of the things we have been doing.

While my colleague Julie has been focusing on the more technical issues of implementing Archivematica for research data. I have been looking at some real research data and exploring in more detail some of the issues we discussed in our phase 1 report.

For the past year, we have been accepting research data for longer term curation. Though the systems for preservation and access to this data are still in development, we are for the time being able to allocate a DOI for each dataset, manage access and store it safely (ensuring it isn't altered) and intend to ingest it into our data curation systems once they are ready.

Having this data in one place on our filestore does give me the opportunity to test the hypothesis in our first report about the wide range of file formats that will be present in a research dataset and also the assertion that many of these will not be identified by the tools and registries in use for the creation of technical metadata.

So, I have done a fairly quick piece of analysis on the research data, running a tool called Droid developed by The National Archives over the data to get an indication of whether the files can be recognised and identified in an automated fashion.

All the data in our research data sample has been deposited with us since May 2015. The majority of the data is scientific in nature - much of it coming from the departments of Chemistry and Physics. (this may be a direct result of expectations from the EPSRC around data management). The data is mostly fairly recent, as suggested by the last modified dates on these files, which range from 2006 to 2016 with the vast majority having been modified in the last five years. The distribution of dates is illustrated below.

Here are some of the findings of this exercise:

Summary statistics

• Droid reported that 3752 individual files were present*

• 1382 (37%) of the files were given a file format identification by Droid

• 1368 (99%) of those files that were identified were given just one possible identification. 12 files were given two possible identifications and a further two were given 18 possible identifications. In all these cases, the identification was done by file extension rather than signature - which perhaps explains the uncertainty

Files that were identified

• Of the 1382 files that were identified: 
• 668 (48%) were identified by signature (which suggests a fairly accurate identification - if a file is identified by signature it means that Droid has looked inside the file and seen something that it recognises. I'm told it does this by some sort of magic!)
• 648 (47%) were identified by extension alone (which implies a less accurate identification)
• 65 (5%) were identified by container. These were all Microsoft Office files - xlsx and docx as these are in effect zip files (which suggests a high level of accuracy)

• 111 (8%) of the identified files had a file extension mismatch - this means that the file extension was not what you would expect given the identification by signature. 
• All but 16 of these files were XML files that didn't have the .xml file extension (there were a range of extensions for these files including .orig, .plot, .xpr, .sc, .svg, .xci, .hwh, .bxml, .history). This isn't a very surprising finding given the ubiquity of XML files and the fact that applications often give their own XML output different extensions.

• 34 different file formats were identified within the collection of research data

• Of the identified files 360 (26%) were XML files. This was by far the most common file format identified within the research dataset. The top 10 identified files are as follows:
• Extensible Markup Language - 360
• Log File - 212
• Plain Text File - 186
• AppleDouble Resource Fork - 133
• Comma Separated Values - 109
• Microsoft Print File - 77
• Portable Network Graphics - 73
• Microsoft Excel for Windows - 57
• ZIP Format - 23
• XYWrite Document - 21

Files that weren't identified

• Of the 2370 files that weren't identified by Droid, 107 different file extensions were represented

• 614 (26%) of the unidentified files had no file extension at all. This does rather limit the chance of identification being that identification by file extension is relied on quite heavily by Droid and other similar tools. Of course it also limits our ability to actively curate this data unless we can identify it by another means.

• The most common file extensions for the files that were not identified are as follows:
• dat - 286
• crl - 259
• sd - 246
• jdf - 130
• out - 50
• mrc - 47
• inp - 46
• xyz - 37
• prefs - 32
• spa - 32

Some thoughts

• This is all very interesting and does back up our assertions about the long tail of file formats within a collection of research data and the challenges of identifying this data using current tools. I'd be interested to know whether for other collections of born digital data (not research data) a higher success rate would be expected? Is identification of 37% of files a particularly bad result or is it similar to what others have experienced?

• As mentioned in a previous blog post, one area of work for us is to get some more research data file formats into PRONOM (a key database of file formats that is utilised by digital preservation tools). Alongside previous work on the top software applications used by researchers (a little of this is reported here) this has been helpful in informing our priorities when considering which formats we would like The National Archives to develop signatures for in phase 3 of the project.

• Given the point made above, it could be suggested that one of our priorities for file format research should be .dat files. This would make sense being that we have 286 of these files and they are not identified by any means. However, here lies a problem. This is actually a fairly common file extension. There are many different types of .dat files produced by many different applications. PRONOM already holds information on two varieties of .dat file and the .dat files that we hold appear to come from several different software applications. In short, solving the .dat problem is not a trivial exercise!

• It strikes me that we are really just scratching the surface here. Though it is good we are getting a few file signatures developed as an output for this project, this is clearly not going to make a big impact given the size of the problem. We will need to think about the community should continue this work going forward.

• It has been really helpful having some genuine research data to investigate when thinking about preservation workflows - particularly those workflows for unidentified files that we were considering in some detail during phase 2 of our project. The unidentified file report that has been developed within Archivematica as a result of this project helpfully organises the files by extension and I had not envisaged at the time that so many files would have no file extension at all. We have discussed previously how useful it is to fall back on identification by file extension if identification by signature is unsuccessful but clearly for so many of our files this will not be worth attempting.

* note that this turns out not to be entirely accurate given that eight of the datasets were zipped up into a .rar archive. Though Droid looks inside several types of zip files, (including .zip, .gzip, .tar, and the web archival formats .arc and .warc) it does not yet look inside .rar, 7z, .bz, and .iso files. I didn't realise this until after I had carried out some analysis on the results. Consequently there are another 1291 files which I have not reported on here (though a quick run through with Droid after unzipping them manual identified 33% of the files so a similar ratio to the rest of the data. Note that this functionality is something that the team at The National Archives intend to develop in the future.

Jenny Mitcham, Digital Archivist