Source: How Linux Works: What Every Superuser Should Know by Brian Ward (2014)


FAT filesystems (msdos, vfat, umsdos) pertain to Microsoft systems. The simple msdos type supports the very primitive monocase variety in MS-DOS systems. For most modern Windows filesystems, you should use the vfat filesystem in order to get full access from Linux. The rarely used umsdos filesystem is peculiar to Linux. It supports Unix features such as symbolic links on top of an MS-DOS filesystem.

Any idea as to what that means?


1 Answer 1


It means that filenames are case-insensitive, so QWERTY.EXE is the same as qwerty.exe (or any mix of lower-case and upper-case letters. However, I've never heard the term monocase used to describe this. Filenames in Unix (and related operating systems) are always case-sensitive.

In early versions of MS-DOS (and also CP/M), filenames were stored in upper-case only, and this would be apparent in directory listings. Later versions of MS-DOS allowed files to be created with mixed upper- and lower-case names, but referencing filenames was still case-insensitive.

Furthermore, in these systems file and directory names are uppercase, although systems that use the 8.3 standard are usually case-insensitive (hence CamelCap.tpu will be equivalent to the name CAMELCAP.TPU).

Wikipedia: 8.3 filename

  • 1
    I've heard the term "monocase" used in this sense a few times.
    – Hot Licks
    Jan 24, 2017 at 12:55
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    @HotLicks Alphabets, scripts, and type faces with only one "case" of letter in them are called unicameral; for example, the Hebrew alphabet and the old insular Uncial script, as well as many roman titling faces, are all unicameral. To have and admit both cases but disrespect them insensitively is something else altogether.
    – tchrist
    Jan 24, 2017 at 13:46
  • Could you please provide more information as to why you think it means that filenames are case-insensitive? "mono", as far as I know, means "one". You would think that this should then mean "only one case". And that can be interpreted as "case-sensitive" which is the complete opposite of what you talk about in your post. Jan 24, 2017 at 19:16
  • @user69786 Done. See edits.
    – Mick
    Jan 24, 2017 at 19:26
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    @tchrist - It may be that the term has been misapplied, and, if so, that would be the very first instance ever of an English word being used inappropriately by computer guys.
    – Hot Licks
    Jan 24, 2017 at 19:54

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