computing Computing is any goal-oriented activity requiring, benefiting from, or creating computing machinery. It includes the study and experimentation of algorithmic processes, and development of both hardware and software. Computing has scientific, ...

, share is a

command Command may refer to: Computing * Command (computing), a statement in a computer language * COMMAND.COM, the default operating system shell and command-line interpreter for DOS * Command key, a modifier key on Apple Macintosh computer keyboards * ...

for

DOS DOS is shorthand for the MS-DOS and IBM PC DOS family of operating systems. DOS may also refer to: Computing * Data over signalling (DoS), multiplexing data onto a signalling channel * Denial-of-service attack (DoS), an attack on a communicat ...

that allows software to perform file locks. Locking files became necessary when

MS-DOS MS-DOS ( ; acronym for Microsoft Disk Operating System, also known as Microsoft DOS) is an operating system for x86-based personal computers mostly developed by Microsoft. Collectively, MS-DOS, its rebranding as IBM PC DOS, and a few o ...

began allowing files to be accessed simultaneously by multiple programs, either through multitasking or

networking Network, networking and networked may refer to: Science and technology * Network theory, the study of graphs as a representation of relations between discrete objects * Network science, an academic field that studies complex networks Mathematic ...

Implementations

On MS-DOS, the command is available in versions 3 and later. The command is also available in

FreeDOS FreeDOS (formerly Free-DOS and PD-DOS) is a free software operating system for IBM PC compatible computers. It intends to provide a complete MS-DOS-compatible environment for running legacy software and supporting embedded systems. FreeDOS can ...

PTS-DOS PTS-DOS (aka PTS/DOS) is a disk operating system, a DOS clone, developed in Russia by PhysTechSoft and Paragon Technology Systems. History and versions PhysTechSoft was formed in 1991 in Moscow, Russia by graduates and members of MIPT, i ...

, and

SISNE plus SISNE plus is a DOS 3.3 compatible clone created by Itautec and Scopus Tecnologia in Brazil prior to the end of the Market Reserve in 1991, which, at that time, forbade the importation of electronic equipment and software for general use. W ...

. The FreeDOS version was developed by Ron Cemer and is licensed under the GPL. DR DOS 6.0DR DOS 6.0 User Guide Optimisation and Configuration Tips
/ref> and

Datalight Datalight was a privately held software company specializing in power failsafe and high performance software for preserving data integrity in embedded systems. The company was founded in 1983 by Roy Sherrill, and is headquartered in Bothell, Was ...

ROM-DOS Datalight was a privately held software company specializing in power failsafe and high performance software for preserving data integrity in embedded systems. The company was founded in 1983 by Roy Sherrill, and is headquartered in Bothell, Was ...

include an implementation of the command.

Windows XP Windows XP is a major release of Microsoft's Windows NT operating system. It was release to manufacturing, released to manufacturing on August 24, 2001, and later to retail on October 25, 2001. It is a direct upgrade to its predecessors, Wind ...

and later versions include

16-bit 16-bit microcomputers are microcomputers that use 16-bit microprocessors. A 16-bit register can store 216 different values. The range of integer values that can be stored in 16 bits depends on the integer representation used. With the two ...

commands (nonnative) for the MS-DOS subsystem that are included to maintain MS-DOS compatibility. The share MS-DOS subsystem command performs functions that are now inherent to

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 ...

. It is available to preserve compatibility with existing files, but has no effect at the

command line A command-line interpreter or command-line processor uses a command-line interface (CLI) to receive commands from a user in the form of lines of text. This provides a means of setting parameters for the environment, invoking executables and pro ...

because the functionality is automatic. The 16-bit MS-DOS subsystem commands are not available on

64-bit In computer architecture, 64-bit integers, memory addresses, or other data units are those that are 64 bits wide. Also, 64-bit CPUs and ALUs are those that are based on processor registers, address buses, or data buses of that size. A ...

editions of Windows.MS-DOS subsystem commands
/ref>

Design

There were five locking modes: *Deny None *Deny Read *Deny Write *Deny All *Compatibility (designed for

backward compatibility Backward compatibility (sometimes known as backwards compatibility) is a property of an operating system, product, or technology that allows for interoperability with an older legacy system, or with input designed for such a system, especiall ...

with existing MS-DOS programs) The program runs as a

Terminate and Stay Resident A terminate-and-stay-resident program (commonly TSR) is a computer program running under DOS that uses a system call to return control to DOS as though it has finished, but remains in computer memory so it can be reactivated later. This technique ...

program and is typically loaded at boot-up.

Syntax

share F:space L:locks */F:space Allocates file space (in bytes) for file-sharing information. */L:locks Sets the number of files that can be locked at one time.

Implementations

Design

Syntax

See also

References

Further reading