Most file systems include attributes of files and directories that control the ability of users to read, change, navigate, and execute the contents of the file system. In some cases, menu options or functions may be made visible or hidden depending on a user's permission level; this kind of user interface is referred to as permission-driven. Two types of permissions are widely available: POSIX file system permissions and access-control lists (ACLs) which are capable of more specific control. File system variations The original File Allocation Table file system has a per-file all-user read-only attribute. NTFS implemented in Microsoft Windows NT and its derivatives, use ACLs to provide a complex set of permissions. OpenVMS uses a permission scheme similar to that of Unix. There are four categories (system, owner, group, and world) and four types of access permissions (Read, Write, Execute and Delete). The categories are not mutually disjoint: World includes Group, which in turn includes Owner. The System category independently includes system users. HFS, and its successor HFS+, implemented in the Classic Mac OS operating systems, do not support permissions. macOS uses POSIX-compliant permissions. Beginning with version 10.4 ("Tiger"), it also supports the use of NFSv4 ACLs in addition to POSIX-compliant permissions. The Apple Mac OS X Server version 10.4+ File Services Administration Manual recommends using only traditional Unix permissions if possible. macOS also still supports the Classic Mac OS's "Protected" attribute. Solaris ACL support depends on the filesystem being used; older UFS filesystem supports POSIX.1e ACLs, while ZFS supports only NFSv4 ACLs. Linux supports ext2, ext3, ext4, Btrfs and other file systems many of which include POSIX.1e ACLs. There is experimental support for NFSv4 ACLs for ext3 and ext4 filesystems. FreeBSD supports POSIX.1e ACLs on UFS, and NFSv4 ACLs on UFS and ZFS. IBM z/OS implements file security using RACF (Resource Access Control Facility) The AmigaOS Filesystem, AmigaDOS supports a permissions system relatively advanced for a single-user OS. In AmigaOS 1.x, files had Archive, Read, Write, Execute and Delete (collectively known as ARWED) permissions/flags. In AmigaOS 2.x and higher, additional Hold, Script, and Pure permissions/flags were added. POSIX permissions Permissions on Unix-like file systems are defined in the POSIX.1-2017 standard, which uses three scopes or classes known as user, group, and others. When a file is created its permissions are restricted by the umask of the process that created it. Classes Files and directories are owned by a user.