transport(1)

PROGRAM
transport - description of the data transport and distributed processing capability within Khoros.

SYNTAX

None. Information page only.

DESCRIPTION

Data transport refers to the method used to transfer data between processes. Data transport mechanisms can be local or remote. Local transport mechanisms include shared memory, files, pipes, and streams; remote transport mechanisms include sockets. Future implementations will include tli, and rpc. With the use of remote data transport, the ability to get input from and output to remote machines is implemented, and distributed processing is made possible. See phantom(1) and phantomd(1).

One limitation of this first version of data transport / distributed processing involves whether or not a transport mechanism provides permanent data storage. By their nature, some transport mechanisms provide permanent data storage, while others do not. Permanent data storage is offered by transport mechanisms such as shared memory and files; it is not provided by sockets, pipes, or streams. When permanent data storage is not available, the scheduler used by cantata will be unable to execute a network of glyphs unless it starts at the very beginning, where initial input is provided in a permanent form. Thus, when using distributed processing, which is implemented via a non-permanent data transport mechanism (sockets) you must click on the "RESET" button and run the network completely through every time. We realize that this limitation is inconvenient and restrictive; in future versions of Khoros, the scheduler used by cantata will be improved so as to eliminate this problem.

The transport mechanisms that are (at least partially) supported by individual Khoros vroutines are:

shm:
    Shared Memory (local transport / permanent storage)

file:
    Standard Unix file (local transport / permanent storage)

pipe:
    Standard Pipes (local transport / no permanent storage)

stream:
    Named stream/pipe (local transport / no permanent storage)

socket:
    Socket transport (remote transport / no permanent storage)

Transport mechanisms used by the cantata visual language are:

shm:
    Shared Memory (local transport / permanent storage)

file
    Standard Unix file (local transport / permanent storage)

socket
    Socket transport (remote transport / no permanent storage)

In the future, other transport mechanisms that may be implemented include:

sunvm:
    Sun's Virtual memory (permanent storage)

tli:
    Sys V Transport Layer Interface

sunrpc:
    Sun's remote procedure call

apollorpc:
    Apollo's remote procedure call

machvm:
    Mach's Virtual Memory

Your computer architecture will dictate which, if any, of these transport mechanisms are available for your use. Note that data transport and distributed processing will not be available on some computer architectures. Also be aware that this "beta" version of data transport in cantata does have limited capability; some transport mechanisms may not always be used even when most appropriate for the situation.

The data transport and distributed processing capability may be taken advantage of either from the cantata visual language, or from individual command line executions of Khoros programs.

For more information on data transports and distributed processing see Vol 1, Chapter 1 of the Khoros manual.

REQUIRED ARGUMENTS

None. Information page only.

OPTIONAL ARGUMENTS

None. Information page only.

EXAMPLES
None.

SEE ALSO
intro(1), phantom(1), phantomd(1), kcp(1), kexec(1), vgparms(3), vutils(3)

RESTRICTIONS

COPYRIGHT
Copyright 1992, University of New Mexico. All rights reserved.