It’s been too long since I’ve had a special discount on FTL. For all of June, you can get Files that Last: Digital Preservation for Everygeek on Smashwords for just $4.00. That’s half off the regular price! The coupon code is KC49Z.
FTL is aimed at anyone with a moderate level of technical knowledge who’s concerned with keeping files from becoming useless over the years. It covers formats, metadata, media, file systems, and more.
The book is 100% DRM-free on Smashwords. I’ve done my best to keep it that way when it’s sold through other platforms but can’t always guarantee it.
In honor of the day, I’m offering 
How to approach the file format validation problem
For years I wrote most of the code for JHOVE. With each format, I wrote tests for whether a file is “well-formed” and “valid.” With most formats, I never knew exactly what these terms meant. They come from XML, where they have clear meanings. A well-formed XML file has correct syntax. Angle brackets and quote marks match. Closing tags match opening tags. A valid file is well-formed and follows its schema. A file can be well-formed but not valid, but it can’t be valid without being well-formed.
With most other formats, there’s no definition of these terms. JHOVE applies them anyway. (I wrote the code, but I didn’t design JHOVE’s architecture. Not my fault.) I approached them by treating “well-formed” as meaning syntactically correct, and “valid” as meaning semantically correct. Drawing the line wasn’t always easy. If a required date field is missing, is the file not well-formed or just not valid? What if the date is supposed to be in ISO 8601 format but isn’t? How much does it matter?
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Posted in commentary
Tagged archiving, JHOVE, preservation, standards