Method for establishing current terminal addresses for system users processing distributed application programs in an SNA LU 6.2 network environment

• US 4,991,089 A
• Filed: 09/30/1988
• Issued: 02/05/1991
• Est. Priority Date: 09/30/1988
• Status: Expired

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Shorter, David U.
• Primary Examiner(s): Eng, David Y.
• Application Number:
  US07/251,279
• Time in Patent Office: 858 Days
• Field of Search: 364/200 MS File, 364/900 MS File, 364/513, 340/825.28
• US Class Current: 709/220
• CPC Class Codes: G06F 9/4843 by program, e.g. task dispatcher, supervisor, operating system
• CPC Class Codes: G06F 9/54 Interprogram communication

Abstract

A method is described which permits a user of an Intelligent Work Station (IWS) in an SNA type network in which communication with the host processor employs LU 6.2 advanced program to program protocols and in which the host processor does not assign a dedicated virtual machine to the user during the period the user is active on the system, to notify the system of the user'"'"'s current terminal address so that distributed applications programs having component parts distributed at the host and the IWS may be executed. When resident counterpart programs of distributed applications are executed by assigning each LU 6.2 conversation to an idle virtual machines from a preestablished pool of virtual machines created by the host processor, rather than to a dedicated virtual machine, the prior art methods that are based on associating the current address of the user with the address of the dedicated virtual are no longer operable. The new method does not require the user to notify the system that the user'"'"'s IWS is active, since the user may want to run programs that do nor involve the host processor and may not want to be distracted with communications from the host and other users. In accordance with the new method a distributed application is provided at the terminal which is invoked by the user when a decision is made to provide the current terminal address to the host. The distributed application issues an LU 6.2 ALLOCATE verb requesting a conversation with the counterpart program resident at the host. The counterpart program is executed at the host by a virtual machine from the pool and establishes a data structure where the USERID of the user and the terminal address of the IWS are associated. The data structure is stored at a location which is scanned by all subsequent LU 6.2 conversation requests from the host and other users for a match of USERIDs. When a match occurs the associated current terminal address of the USERID is inserted into the request and sent to the IWS by the system.

Claims

1. A method for controlling the processing of host originated conversation requests for known Users of an SNA type network that processes distributed application programs in accordance with LU 6.2 protocols in which a conversation is selectively established between portions of a distributed application program, one portion being stored and executed at one of plurality of Intelligent Work Stations (IWSs) which is selectively connectable to said network and another portion being stored at a host processor, said processor having a Virtual Machine Pool Manager (VMPM) for creating a pool of virtual machines and for managing the assignment of each machine to process the said another portion, said assignment being terminated and said assigned virtual machine being returned to said pool at the time that a processed conversation is terminated, said method preventing a host originated conversation request addressed to a first user having a specific USERID from being processed by an assigned virtual machine unless specifically authorized by said first user designating the ID of one said IWS to which said host originated conversation requests are to be sent, while permitting a conversation request by said first user originating from an IWS to be processed by a virtual machine assigned by said VMPM, said method comprising the following steps,

(A) providing a second distributed application program having one portion resident at said first IWS and the counterpart portion resident on said host to authorize the processing by an assigned said virtual machine of host originated conversation requests addressed to said first user,

(B) invoking at said first IWS said one portion of said second application program to transmit an ALLOCATE verb requesting a conversation with said counter part portion, said ALLOCATE verb including said USERID and the ID of said first IWS at which said first user is currently located,

(C) processing said ALLOCATE conversation request at said host including the steps of,

(1) creating an Identification Control Block Entry (ICBE) data structure for storing the said USERID of said first user and said first IWS ID, and

(2) appending said ICBE onto a chain of ICBEs at a location in storage that is accessible to each said virtual machine to permit said first IWS ID and said first USERID user to be determined by each virtual machine assigned to process a host originated request for a conversation with said first USERID,

(D) processing with an assigned virtual machine a host originated request for a conversation with said first USERID, including the step of

(1) scanning said chain of ICBEs to determine the IWS ID at which said specified User is currently located, and

(2) transmitting said request only if said IWS ID is determined in said step of scanning.

2. The method recited in claim 1 including the further step of,

(A) storing in said ICBE data transferred to said host with said ALLOCATE to relate said first USERID and the IWS ID that issued said ALLOCATE verb.

3. The method recited in claim 2 including the further step of,

(A) issuing a DEALLOCATE verb to said first IWS ID from said host to terminate said conversation.

4. The method recited in claim 1 in which said step of processing includes the further steps of,

(A) issuing an ALLOCATE verb at said host, requesting a conversation with said first USERID, and

(B) determining if said first USERID is accepting conversation requests by,

(1) scanning said chain of ICBEs for an entry containing said first USERID, and

(2) transmitting the ALLOCATE verb to IWS ID stored in the ICBE containing said first USERID when said USERID is found by said scanning step.

5. The method recited in claim 4 including the further step of,

(A) terminating said step of processing when said step of scanning determines that said first USERID has not been stored in a scanned ICBE.