cache

Ubik

DFS: A library of utilities that the DFS FL server and the DFS Backup Server use to keep individual copies of the FLDB and the Backup Database. See also secondary site, synchronization site.

UFS

See UNIX File System.

unauthenticated mask

The maximum set of permissions granted when access to the object is not authenticated. Unauthenticated access is granted only if the caller matches some ACL entry (frequently the any_other entry) and if the required permission is granted by both the entry and the mask.

unexport

RPC: To remove binding information from a server entry in a name service database. See also export.

uniquifier

DFS: A piece of data that, in combination with a fileset ID, produces a globally unique identifier.

Universal Unique Identifier (UUID)

RPC: An identifier that is immutable and unique across time and space. A UUID can uniquely identify an entity such as an RPC interface or object. See also interface UUID, object UUID, type UUID.

UNIX File System (UFS)

A section of the UNIX file tree that is physically contained on a single device or disk partition and that can be separately mounted, dismounted, and administered.

unmarshalling

RPC: The process by which a stub disassembles incoming network data and converts it into local data in the appropriate local data representation. See also marshalling, network data.

unpredictable

A violation of an architecture rule that an implementation is not required to report. Results can include an error report from a threads call, the operating system, or the hardware; a hang or deadlock of the program; or an incorrect operation of the program without indication of error. See also illegal.

upclient

DFS: A process that runs on DFS server machines, taking copies of common configuration files and new DFS server process binary files from central sources. See also Update Server, upserver.

update propagation

An immediate attempt to apply a change to all replicas of the CDS directory in which the change was just made. An update propagation delivers changes in a more efficient and timely way than a skulk, which is the periodic distribution of a whole collection of changes.

Update Server

DFS: A process that guarantees that all DFS server machines in a cell have the same versions of common configuration files and the same versions of DFS binary files appropriate for their machine types. It has a server portion called the upserver and a client portion called the upclient. See also upclient, upserver.

Update Timestamp (UTS)

An attribute that identifies the time at which the most recent change was made to any attribute of a particular CDS name. For directories, the UTS reflects changes made only to attributes that apply to the directory as a whole (not one of its replicas).

upserver

DFS: A process that runs on DFS server machines, making local copies of common configuration files and new DFS server process binary files available to other DFS server machines. See also upclient, Update Server.

user

GDS: The end user of the directory; the entity or person that accesses the directory. A user can be an application program that is calling the directory interface on behalf of a human user.

user data

DFS: Data such as ASCII and binary files that resides in a fileset. The data is manipulated and accessed by users of the file system.

User Datagram Protocol (UDP)

A protocol of the Internet Protocol (IP) family.