Resurrecting the first Dutch web index: NL-menu revisited

24 April 2018

NL-menu was the first Dutch web index. The site was originally founded by a consortium of SURFnet, Dutch universities and the KB. From the mid-nineties onwards it was maintained solely by the KB. NL-menu was discontinued in 2004, after which the site was taken offline. In 2006 the domain name was sold to a private company that used it for hosting a web index that was partially based on the original NL-menu site.

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Update on Isolyzer: UDF, HFS+ and more!

12 July 2017

Earlier this year I blogged about Isolyzer, a tool designed to help the detection of broken ISO images. Today I released a shiny new beta version that adds a significant amount of new functionality. Below is an overview of the main changes, followed by some warnings and caveats.

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Image and Rip Optical Media Like A Boss!

19 June 2017

Over the last months we’ve been working on the development of a provisional workflow for preserving the content of optical media in our collection. The main result thus far is Iromlab, a custom workflow application that streamlines the imaging and ripping process. This blogpost gives an overview of Iromlab, as well as the reasons why we created it in the first place.

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Policy-based assessment with VeraPDF - a first impression

01 June 2017

Some four years ago I wrote a blog post that demonstrated how Apache Preflight (the PDF/A validator tool that is part of Apache PDFBox) can be used to detect features in a PDF that are potential preservation risks. A follow-up blog applied Schematron rules to the Preflight output in an attempt at doing policy-based assessments. The results of that work were quite promising, but dealing with Preflight’s multitude of (especially font-related) validation errors proved to be a challenge.

The idea of using a PDF/A validor for policy-based assessments of “regular” PDF files (i.e. PDFs that are not necessarily PDF/A) was explicitly addressed as a use case for veraPDF. With VeraPDF now having entered its “final testing phase”, I thought this was a good time for a small test-drive of veraPDF’s capabilities in this area. All test results are based on VeraPDF 1.4.7.

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Imaging CD-Extra / Blue Book discs

25 April 2017

The development work on an imaging/ripping workflow for optical media is shaping up steadily, and you can expect a write-up with more information about our software and hardware setup here in the near future (you can get a sneak peek here). However, this blog is about a very specific problem that we ran into while testing the workflow with a selection of discs from our collection. This selection included a few discs that follow the Blue Book standard (also known as CD-Extra). This standard defines a method for combining audio and data tracks on one disc. A CD-Extra disc contains two sessions, where the first session holds all audio tracks, and the second session holds a data track. Blue Book was (and still is) widely used for audio CD’s with bonus videos or software.

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