Browse Prior Art Database

Synchronized Connection

IP.com Disclosure Number: IPCOM000100260D
Original Publication Date: 1990-Mar-01
Included in the Prior Art Database: 2005-Mar-15
Document File: 2 page(s) / 93K

Publishing Venue

IBM

Related People

Burkes, DL: AUTHOR [+2]

Abstract

This article defines a method for connecting data base management systems (DBMSs) which are loosely coupled in a distributed network to support distributed data base requests. A DBMS is said to be connected to another DBMS when both sides have verified each other, exchanged functional attributes, and have established a two-way communications path for system messages. Once a DBMS is connected, distributed data base requests can be sent to the connected DBMS. This invention provides a safe, efficient and synchronous method for connecting two DBMSs using only one-way communications paths. A one-way communications path allows only one of the DBMS to send a message at a time. The DBMS must give up control of the path before the other DBMS can send a message.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 52% of the total text.

Synchronized Connection

       This article defines a method for connecting data base
management systems (DBMSs) which are loosely coupled in a distributed
network to support distributed data base requests.  A DBMS is said to
be connected to another DBMS when both sides have verified each
other, exchanged functional attributes, and have established a
two-way communications path for system messages.  Once a DBMS is
connected, distributed data base requests can be sent to the
connected DBMS.  This invention provides a safe, efficient and
synchronous method for connecting two DBMSs using only one-way
communications paths.  A one-way communications path allows only one
of the DBMS to send a message at a time. The DBMS must give up
control of the path before the other DBMS can send a message.

      For system messages, a two-way communications path is needed,
because a DBMS needs to be able to send system messages (known as
datagrams) at any time without having to get control from the other
DBMS.

      This system communications path is made up of two one-way
communications links called system links, with each DBMS having a
"send link" and a "receive link" to every DBMS with which it is
connected.

      The connection procedure requires two active processes on every
DBMS in the network.  One of these processes, known as the "outbound
connect process", manages ALL send links to connected DBMSs.  The
other process, known as the "inbound connect process", manages ALL
receive links from connected DBMSs.  A DBMS may not communicate with
any other DBMS until these processes are active.  Each process has an
associated request queue which it services.

      A connection request to a remote DBMS is initiated by placing a
connect request on the outbound connect process queue.  The
requesting process is suspended pending completion of the connect
request.  Eventually, the request is dequeued by the outbound connect
process.  The outbound connect process first determines if a
connection already exists with the target DBMS as, for example, if a
process were to make a connection request while another request, from
some other process, was on the request queue. If a connection already
exists, the requesting process is simply resumed.  Otherwise, a
connection with the remote DBMS must be established.

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