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A-Z glossary of PageSeeder concepts

File system

PageSeeder relies on the file system to store documents and binary files. For information about files managed by PageSeeder, see folders and files.

Common file systems

The following table summarizes the important features and limitations of common file systems:

Max volume size4 Tib-32 Tib1 EiB32 Gib16 EiB8 EiB
Max file size16 Gib-2 Tib16 Tib4 Gib16 EiB8 EiB
Max filename length255 bytes255 UTF-16 characters 
Max pathname length4,096 bytes32,760 UTF-16 characters
Allowed chars in filenamesAll bytes
(except NUL)
Any Unicode character
(except NUL and '/')
Any Unicode character
(including NUL)
Max number of filesDepends on volume size4 billion264-1232-1
Case sensitiveYesYesNoOptional - OS prevents same case-insensitive name in a directory
Case preservingYesYesYesYesYes

Note that additional limitations are imposed by the operating system.

Other file systems

The following file systems are used for external storage devices such as USB keys, SD cards, DVD and CD-ROM.

Max volume size2 TB128 PiB
Max file size16 EB128 PiB
Max filename length255 bytes255 UTF-16 characters
Max pathname length1023 bytes
Allowed chars in filenamesAny Unicode except NULUnicode UTF-16 except:
  • +0000 (NUL) through U+001F
  • / (slash)
  • \ (backslash)
  • : (colon)
  • * (asterisk)
  • ? (Question mark)
  • " (quote)
  • < (less than)
  • > (greater than)
  • | (pipe)
Max files in directories2,796,202
Max number of files
Reserved file names

Operating system limits

Operating systems impose additional limits to the file system. Most use Unicode in practice.


  • Unicode support by default using UTF-8 encoding.
  • File names starting with a ‘.’ are hidden.

Microsoft Windows

  • Unicode using by default UTF-16 encoding.
  • Reserved characters in filenames:
    • U+0000 (NUL) through to U+0031.
    • < (less than).
    • > (greater than).
    • : (colon).
    • " (double quote).
    • / (forward slash).
    • \ (backslash).
    • | (vertical bar or pipe).
    • ? (question mark).
    • * (asterisk).
  • Reserved file names:
    • CON, PRN, AUX, NUL, COM1, COM2, COM3, COM4, COM5, COM6, COM7, COM8, COM9, LPT1, LPT2, LPT3, LPT4, LPT5, LPT6, LPT7, LPT8, and LPT9.
    • Use of filename even with an extension (e.g. NUL.txt) is not recommended.
    • File names shouldn’t end with a ‘.’ or ‘ ’ (space).


  • Unicode using by default UTF-16 encoding.
  • Reserved characters:
    • : (colon).
    • / (slash).
Created on , last edited on