Xref: utzoo comp.lang.c++:9327 comp.sys.isis:390 comp.databases:6996 comp.os.mach:513
Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!sun-barr!apple!brutus.cs.uiuc.edu!wuarchive!swbatl!cbs
From: cbs@swbatl.sbc.com (Brad Slaten 529-7636)
Newsgroups: comp.lang.c++,comp.sys.isis,comp.databases,comp.os.mach
Subject: Data sharing among lightweight tasks
Keywords: ISIS, distributed objects, lightweight tasks
Message-ID: <1990Aug30.164153.25008@swbatl.sbc.com>
Date: 30 Aug 90 16:41:53 GMT
Organization: Southwestern Bell
Lines: 26


    Our current application is using an object-oriented implementation
under the ISIS lightweight tasking library and Unix.  We have provided an
interface to the Inter-process Communication (IPC) mechanism such that
the application does not know when an object with which it is
communicating requires IPC.  The problem which occurs is that in
making the IPC transparent, the lightweight task context switch is
also transparent.  The problem results from the fact that certain
objects are shared among multiple tasks.  When a context switch occurs
from one task to another, any or all shared objects may be modified by
a different task without the initial task having knowledge of this.
    Any and all thoughts (regardless of how wild) on this problem, or
alternate approaches are welcome.  Please send via e-mail.

Cheers
Brad Slaten

P.S. We have thought about placing automatic checks on all shared
    objects upon return from the transparent IPC, but do not care to
    do recursive checks on objects for each IPC.

    We have considered making shared objects resources, but have
    not come up with a good solution to the deadlock problem.

-- 
cbs@swbatl:		Brad Slaten - 529-7636