How does Linux determine filename case on ISO 9660?

Thursday, October 23, 2014
Here is a quote from this article: ISO 9660 is not a complex file system, but has a few quirks that are worth remembering. It seems that some operating systems also create non-compliant CDs, so beware! The main example of this is the character set that is available for file names. Strictly,filenames may only consist of uppercase letters A-Z, digits, dots, and underscores. Further there is a semicolon which separates the visible file name from its version number suffix. Many operating systems also allow lower case letters and other characters. linux's VFS displays lower case filenames to the user despite the CD contents actually containing upper case characters. So my question is, how does linux know which letters are supposed to be uppercase and which letters are supposed to be lowercase, when on the CD they are all uppercase? ...

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