Using the Desktop Client or WebDav it is possible to synchronize data with Research Drive from various operating systems with different file systems which all have different rules for file naming length and special characters. For example in Mac you may be able to use a space after the name of a file while in Windows this is not permitted. To make sure that your data is interoperable it is important that you use file and folder naming which will not conflict on different systems. The easiest way to do this is to use simple(but informative) file and folder naming without any special characters at all. In fact, making file names readable and compatible with multiple file systems is a FAIR principle because it ensures interoperability. 

Special Characters

One of the main issues we see is that certain special characters are not permitted by certain operating systems. When you use characters that are "special", you may get the message; "The filename is a reserved name on this file system".
The set of characters that is permitted in a file name can be determined by the file system and by the local code set. 

This message indicates that the file will not be synchronized. This is caused because the name of your file contains certain characters that should not appear in file names. 
Most likely, these characters are used by your Operating System (for example, Windows) to function properly behind the scenes.
Therefore, the following characters should not be used either:

< (less then)
> (greater then)
: (colon)
" (double qoute)
/ (forward slash)
\ (backslash)
| (vertical bar or pipe)
? (question mark)
* (asterisk)

To solve this problem, we recommend that you check if your file name contains any of the above characters.
If it does, we recommend replacing or deleting those characters. If the file is then uploaded again, this error message will no longer be caused.

File Name Lengths

Depending on the underlying file system used individual files may have file length limitations as well limitations on the length of the full path. This means when synching data to these systems there could be issues if the file names are too long. These lengths are summarized for various file systems below. The advice is to think about cross-compatibility for all systems.

Filesystemmax. Path Lengthmax. Filename Length

(*) Btrfs

No limit defined

255 bytes

(*) ext2

No limit defined

255 bytes

(*) ext3

No limit defined

255 bytes

(*) ext4

No limit defined

255 bytes

(*) XFS

No limit defined

255 bytes

(*) ZFS

No limit defined

255 bytes

APFS

Unknown 

255 UTF-8 characters

FAT32

32,760 Unicode characters with each path component no more than 255 characters

8.3 (255 UCS-2 code units with VFAT LFNs)

exFAT

32,760 Unicode characters with each path component no more than 255 characters

255 UTF-16 characters

NTFS

32,767 Unicode characters with each path component (directory or filename) up to 255 characters long (MAX_PATH).

Starting in Windows 10, version 1607, MAX_PATH limitations have been removed from common Win32 file and directory functions. However, you must opt-in to the new behavior. For more details see Enable Long Paths in Windows 10, Version 1607, and Later

255 characters

Case Sensitivity

A smaller problem is that certain operating systems are and aren't case sensitive. Linux and Unix systems are usually case sensitive so the files Example.txt and example.txt would be seen as different files. However Windows and Mac(by default) are not case sensitive so this could cause a synchronisation error. 

Reserved File Names

The following file names are reserved by operating systems and should never be used. 

Windows

CON, PRN, AUX, NUL COM1, COM2, COM3, COM4, COM5, COM6, COM7, COM8, COM9, LPT1, LPT2, LPT3, LPT4, LPT5, LPT6, LPT7, LPT8, LPT9

Sources:

https://doc.owncloud.com/desktop/next/filenames.html 

https://doc.owncloud.com/server/next/admin_manual/troubleshooting/path_filename_length.html




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