Browse Prior Art Database

Method of Managing Access to Shared Memory in Multitasking Operating Systems Which Support Message Passing

IP.com Disclosure Number: IPCOM000108023D
Original Publication Date: 1992-Jan-01
Included in the Prior Art Database: 2005-Mar-22
Document File: 1 page(s) / 52K

Publishing Venue

IBM

Related People

Baldiga, FP: AUTHOR [+2]

Abstract

Disclosed is a programming technique to manage and serialize access to memory shared between two different multitasking operating systems which support the message passing form of inter-process communication. This technique can also be used in a single multitasking system which supports message passing.

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This is the abbreviated version, containing approximately 61% of the total text.

Method of Managing Access to Shared Memory in Multitasking Operating Systems Which Support Message Passing

       Disclosed is a programming technique to manage and
serialize access to memory shared between two different multitasking
operating systems which support the message passing form of
inter-process communication.  This technique can also be used in a
single multitasking system which supports message passing.

      In a system consisting of one or more multitasking environments
or platforms, access to a shared area of memory may need to be
serialized.  There may be a number of processes accessing the shared
memory concurrently. Semaphores may not be supported or may not be
common across the platforms.  Furthermore, it is often necessary for
a process on one platform to allocate an area of the memory buffer
and a different process, which has been passed a pointer to it, to
free or deallocate it at a future time. This technique consists of
three separate stages:
      1.   Initialization stage - The shared memory is reserved or
allocated on one of the platforms and a mailbox is created.  The area
of memory is then suballocated into blocks and the mailbox is
initialized with messages, one for each of the blocks.  Each message
contains a pointer to a unique block of memory.  For example, suppose
4K (4096 bytes) of shared memory is allocated and broken up into 16
256-byte blocks.  This requires that 16 messages be sent to the
mailbox, each one cont...