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File System Semantics

Files.com is a cloud-based managed file transfer platform optimized for business-to-business file transfer. The semantics of the system are designed to "just work" for the majority of business-to-business file transfer needs. Since file transfer as a domain has been around far longer than Files.com — the first file transfer tools were built in the early 1970s — we've paid close attention to how major existing software packages work and to the general expectations around business-to-business exchanges in the real world.

Files.com implements a virtual filesystem internally, and all filesystem logic is built into the Files.com application itself. Files.com does not use Windows or UNIX file systems as a model for its path conventions. The sections below describe the key differences.

Permissions

Files.com uses its own Permissions scheme, which operates differently from POSIX or NTFS permissions. See Permissions to understand how permissions work in Files.com. With proper use of Files.com's permissions system, you can achieve any access control scheme your application requires.

When you access Files.com through integrations such as FTP, SFTP, or WebDAV, those integrations sometimes report POSIX permissions when you list a folder. These permissions are dummy values and can be disregarded.

Folder (Directory) Separation

Files.com path names use exactly one forward slash (/) between folders in the path, and never use a slash at the beginning or end of the path. Path names may not contain a backslash (\).

Spaces at the End of Folder Names

Trailing whitespace characters at the end of folder names are not allowed on the Files.com platform. This includes the space character (" "), the tab character (" " or \t), the newline character (\n), and the carriage return character (\r).

The reason for this limitation is compatibility, particularly with the FTP protocol, which remains a widely used file transfer method among our customers. FTP was built around ASCII text-based commands and was not designed to reliably handle trailing whitespace in folder names. Trailing whitespace is often trimmed, ignored, or misinterpreted during transfers and directory listings, which produces errors and unexpected behavior when working with folders that include such characters.

Spaces at the End of File Names

The Files.com platform allows file names to end with trailing whitespace characters: the space character (" "), the tab character (" " or \t), the newline character (\n), and the carriage return character (\r).

Some other operating systems, file transfer clients, and file transfer protocols do not support trailing whitespace in file names. Clients and protocols that don't support it remove or substitute those whitespace characters when transferring or uploading files to Files.com.

No Slashes Inside File/Folder Names

To maintain compatibility with remote servers, which typically use a slash character to delimit folder names, you may not use a slash character inside a specific file or folder name.

Maximum Filename Length

The maximum length of a filename path (including all its parent folders) is 550 characters, including the file extension.

File Modification Times

By default, file modification times are not editable by users in Files.com, because allowing edits can be a security concern. Some applications, such as file synchronization clients, need the ability to set the file modification time, and Files.com offers a setting that enables this capability. To enable user-provided modified times in Files.com, type File "last modified date" semantics in the search box at the top of every page and click the matching result. Adjust the setting as needed.

Showing the user-provided date affects FTP, SFTP, WebDAV, and the web interface. Through our API or SDKs, you get access to both timestamps: the user-set timestamp and our own timestamp of the file's actual most recent modification time.

When previewing a file online, the following timestamps are shown:

Uploaded - The date and time that the file was uploaded to Files.com.

Modified - The date and time that the file was last modified on Files.com.

Modified on source system - The date and time that the file was last modified on the system that uploaded the file. This timestamp is displayed only if a date and time were provided by the source system during upload and the value differs from the Modified time value.

In POSIX-based filesystems and in NTFS, you can create pointers to files via hard links or symbolic links. Windows calls these Shortcuts. Files.com does not currently support either hard links or symbolic links.

Destructive Move/Copy

In a POSIX-based filesystem, a move or copy operation can be destructive, overwriting an existing file when the destination already exists. In Files.com, the operation fails when the destination already exists, which prevents the existing file from being overwritten.

Applicability to Remote Server Mount and Sync

If you are using our Sync or Remote Server Mount capabilities, additional restrictions related to the Remote Server may apply. As a general rule, Files.com applies both its own restrictions and those of the remote server.

For example, spaces at the end of file or folder names are not allowed on a Remote Server Mount, even if the remote supports them. File and folder names that are not supported by the remote mount are also not allowed. Attempting either produces an error at the time of file creation or upload.

A file may fail to sync to a remote server when the filename is not accepted on the remote server, and a file may fail to sync to Files.com from a remote server when the filename is valid on the remote but not on Files.com. For example, remote filenames ending in a space character or containing a slash character are not allowed on Files.com. Both scenarios produce failures in the Sync logs.

Invalid File or Folder Names

Remote servers commonly prohibit certain characters in file and folder names. When you see issues with invalid file or folder names, modify the names to remove the prohibited characters.

Remote servers may also restrict the length of the file or folder name. Common length limits are 160 characters or 55 characters. Some remote servers calculate the total length as just the file or folder name including any extension, while others use the sum of the whole folder path, file name, extension, and temporary suffix. To resolve length errors, shorten the names of files and folders so they fall below the remote server's limits.

On the Files.com side, the path limit is 550 characters for the full path, including folder names.