A stub file is a
computer file
A computer file is a computer resource for recording data in a computer storage device, primarily identified by its file name. Just as words can be written to paper, so can data be written to a computer file. Files can be shared with and transfe ...
that appears to the user to be on
disk
Disk or disc may refer to:
* Disk (mathematics), a geometric shape
* Disk storage
Music
* Disc (band), an American experimental music band
* ''Disk'' (album), a 1995 EP by Moby
Other uses
* Disk (functional analysis), a subset of a vector sp ...
and immediately available for use, but is actually held either in part or entirely on a different storage medium. When a stub file is accessed,
device driver
In computing, a device driver is a computer program that operates or controls a particular type of device that is attached to a computer or automaton. A driver provides a software interface to hardware devices, enabling operating systems and ot ...
software intercepts the access, retrieves the data from its actual location and writes it to the file, then allows the user's access to proceed. Typically, users are unaware that the file's data is stored on a different medium, though they may experience a slight delay when accessing such a file.
File stubbing, the act of creating stub files, is a
Hierarchical storage management (HSM) concept.
Purpose
The usual purpose of stubbing files is to move data from an expensive high-speed storage device such as a computer's hard drive to lower cost storage such as a magnetic tape, or an electro-optical disk, while not requiring users to know how to use specialised storage software to retrieve the data. It also allows a
system manager to enforce the use of low cost storage when users would prefer to store their files on the highest availability, and highest cost, media supplied.
Availability
Stubbing is a feature of many commercial file backup and archiving packages and is available for
Microsoft Windows
Windows is a group of several proprietary graphical operating system families developed and marketed by Microsoft. Each family caters to a certain sector of the computing industry. For example, Windows NT for consumers, Windows Server for serv ...
,
Novell NetWare,
Linux
Linux ( or ) is a family of open-source Unix-like operating systems based on the Linux kernel, an operating system kernel first released on September 17, 1991, by Linus Torvalds. Linux is typically packaged as a Linux distribution, which ...
and other operating systems.
See also
*
BridgeHead Software
* Moonwalk (software)
*
IBM Tivoli Storage Manager
IBM Spectrum Protect (Tivoli Storage Manager) is a data protection platform that gives enterprises a single point of control and administration for backup and recovery. It is the flagship product in the IBM Spectrum Protect (Tivoli Storage Mana ...
*
OpenStore for File Servers
*
Reparse point An NTFS reparse point is a type of NTFS file system object. It is available with the NTFS v3.0 found in Windows 2000 or later versions. Reparse points provide a way to extend the NTFS filesystem. A reparse point contains a reparse tag and data that ...
References
External links
{{reflist
Computer data storage