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Enhanced Inter-program Data Transfer (also known as “Big COMMAREAs”)

Enhanced Inter-program Data Transfer (also known as “Big COMMAREAs”). Steve Zemblowski zem@us.ibm.com. Session Agenda. The 32k COMMAREA “problem” The “solution” Channels and Containers Application programming interface EXEC CICS Java Migration Global and task related user exits

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Enhanced Inter-program Data Transfer (also known as “Big COMMAREAs”)

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  1. Enhanced Inter-program Data Transfer(also known as “Big COMMAREAs”) Steve Zemblowski zem@us.ibm.com

  2. Session Agenda • The 32k COMMAREA “problem” • The “solution” • Channels and Containers • Application programming interface • EXEC CICS • Java • Migration • Global and task related user exits • User replaceable modules • Applications • Monitoring and statistics

  3. The “Problem” • A 32k COMMAREA limitation exists for: • Program to program communication • In a single CICS region • LINK • XCTL • Across CICS regions • Distributed Program Link • Task to task communication • In a single CICS region and across CICS regions • START with data • RETURN

  4. The “Problem”… • Techniques for circumventing the 32k limit • Passing addresses of large storage areas • Single region solution • Placing data in Temporary Storage • Placing data in WebSphere MQ • Using Business Transaction Services (BTS)

  5. The “Solution” • Is not a multi-megabyte COMMAREA • Larger COMMAREA sizes would exacerbate current problems • Data structure complexity • e.g. Overloaded copybooks • Efficient transmission • Code page conversions • DFHCNV mechanism is not easy • Object code compatibility • What about EIBCALEN?

  6. The “Solution”… • Container • Named block of data designed for passing information between programs • “Named” COMMAREAs • No CICS enforced size limitation • Channels are stored above the line but below the bar • Multiple containers can be passed between programs • Channel • A group of Containers • No limit on the number of Containers in a Channel • Non-persistent • Non-recoverable resource • Specified on LINK, XCTL, START and RETURN commands • Only one channel can be passed

  7. The “Solution”… Channel_A Container_One Container_Two Container_Three

  8. Program A EXEC CICS LINK PROGRAM(‘PROGRAMB’) CHANNEL(‘EMPLOYEE_INFO’) Program B Program A EXEC CICS LINK PROGRAM(‘PROGRAMB’) CHANNEL(‘EMPLOYEE_INFO’) Program B EXEC CICS LINK PROGRAM(‘PROGRAMC’) CHANNEL(‘EMPLOYEE_INFO’) Program C Typical Scenarios for using Channels • One program / One channel • One channel / Multiple programs • The Channel is the interface to a Component Employee Inquiry component

  9. Program A EXEC CICS LINK PROGRAM(‘PROGRAMC’) CHANNEL(‘EMPLOYEE_INFO’) Program C Program B EXEC CICS LINK PROGRAM(‘PROGRAMC’) CHANNEL(‘PAYROLL_INFO’) Program A EXEC CICS LINK PROGRAM(‘PROGRAMB’) CHANNEL(‘EMPLOYEE_INFO’) EXEC CICS LINK PROGRAM(‘PROGRAMC’) CHANNEL(‘PAYROLL_INFO’) Program B Program C Typical Scenarios for using Channels… • One program / Multiple channels

  10. Program A EXEC CICS LINK PROGRAM(‘PROGRAMC’) CHANNEL(‘PUBLIC_INFO’) Program A EXEC CICS LINK PROGRAM(‘PROGRAMC’) CHANNEL(‘EMPLOYEE_VER1’) Program C Program C Program B EXEC CICS LINK PROGRAM(‘PROGRAMC’) CHANNEL(‘PRIVATE_INFO’) Program B EXEC CICS LINK PROGRAM(‘PROGRAMC’) CHANNEL(‘EMPLOYEE_VER2’) Typical Scenarios for using Channels… • One program / Multiple channels

  11. Channels • The current channel • The channel, if any, passed to the program by: • LINK or XCTL • START or RETURN • Does not change during the life of the program • The program may create other channels • Default for EXEC CICS commands that do not explicitly specify a channel name

  12. Program A EXEC CICS LINK PROGRAM(‘PROGRAMB’) CHANNEL(‘EMPLOYEE_INFO’) Current Channel: none Program B EXEC CICS LINK PROGRAM(‘PROGRAMC’) CHANNEL(‘EMPLOYEE_INFO’) Current Channel: EMPLOYEE_INFO Program C EXEC CICS LINK PROGRAM(‘PROGRAMD’) Current Channel: EMPLOYEE_INFO Program D EXEC CICS LINK PROGRAM(‘PROGRAME’) CHANNEL(‘MANAGER_INFO’) Current Channel: none Program E EXEC CICS RETURN Current Channel: MANAGER_INFO Channels…

  13. Channels… • Channel scope • Application programs from which the channel can be accessed • Applications can only access the current channel • CICS may create read-only containers • Programs can create new channels • For use in program transfer to a different program • When no program in the link stack can access a channel it is deleted • Occurs at EXEC CICS RETURN or XCTL

  14. Scope of Channel EMPLOYEE_INFO Program A EXEC CICS LINK PROGRAM(‘PROGRAMB’) CHANNEL(‘EMPLOYEE_INFO’) Current Channel: none Program B EXEC CICS LINK PROGRAM(‘PROGRAMC’) CHANNEL(‘EMPLOYEE_INFO’) Current Channel: EMPLOYEE_INFO Program C EXEC CICS LINK PROGRAM(‘PROGRAMD’) Current Channel: EMPLOYEE_INFO Scope of Channel MANAGER_INFO Program D EXEC CICS LINK PROGRAM(‘PROGRAME’) CHANNEL(‘MANAGER_INFO’) Current Channel: none Program E EXEC CICS RETURN Current Channel: MANAGER_INFO Channels…

  15. Program B EXEC CICS LINK PROGRAM(‘PROGRAMC’) CHANNEL(‘MANAGER_INFO’) EXEC CICS XCTL PROGRAM(‘PROGRAMD’) CHANNEL(‘PAYROLL_INFO’) Current Channel: EMPLOYEE_INFO Program D EXEC CICS LINK PROGRAM(‘PROGRAME’) CHANNEL(‘PAYROLL_INFO’) EXEC CICS RETURN Current Channel: PAYROLL_INFO Program C EXEC CICS RETURN Current Channel: MANAGER_INFO Program E EXEC CICS RETURN Current Channel: PAYROLL_INFO Channels… Program A EXEC CICS LINK PROGRAM(‘PROGRAMB’) CHANNEL(‘EMPLOYEE_INFO’) X

  16. Channels… • Lifetime • Creation • A channel is created by naming it on a command • EXEC CICS PUT CONTAINER CHANNEL • EXEC CICS MOVE CONTAINER TOCHANNEL • EXEC CICS LINK PROGRAM CHANNEL • EXEC CICS XCTL PROGRAM CHANNEL • EXEC CICS RETURN TRANSID CHANNEL • EXEC CICS START TRANSID CHANNEL • Deletion • A channel is deleted when it goes out of scope to any program in the linkage stack

  17. Channels… • “Best” practices for performance and reduced complexity • Use separate containers for input and output • Use a dedicated container for error information • Use separate containers for each structure • Use separate containers for different data types • e.g. Character data and binary data • Use separate containers for “read only” versus read/write data • Use separate containers for large amounts of data • Define the channel and container names in a copybook

  18. Channels… • EXEC CICS ASSIGN CHANNEL • CHANNEL (data-area) • returns the 16 character name of the program’s current channel, if one exists; otherwise returns blanks. • Used to discover the channel passed to a program

  19. Containers • Constructing and using a channel • EXEC CICS PUT CONTAINER CHANNEL • Creates a channel and places data into a container within the channel • EXEC CICS GET CONTAINER CHANNEL • Retrieve the container data passed to the called program • EXEC CICS LINK PROGRAM CHANNEL • Links to the program, on a local or remote system, passing the channel and container data • EXEC CICS START TRANSID CHANNEL • Starts a task, on a local or remote system, copying the named channel and container data and passing it to the started task • EXEC CICS RETURN TRANSID CHANNEL • Returns control to CICS, passing the channel and container data to the next transaction id

  20. Containers… • EXEC CICS PUT • CONTAINER (data-value) • Specifies the name (1-16 characters) of the container in which data is to be placed. Do not use names beginning with DFH, • CHANNEL (data-value) • Optional. Specifies the name of the channel that owns the container. If the channel name is not specified the current channel is used. • FROM (data-area) • Specifies the data area from where the data to be saved is read. • FLENGTH (data-value) • Specifies the length of the data area to be saved. • FROMCCSID (data-value) • Specifies the current Coded Character Set of the character data to be put into the container. Defaults to the CCSID of the local CICS region. • DATATYPE (CVDA) • BIT • Default value. Bit data. The data in the container cannot be converted. • CHAR • Character data. The data is in the code page specified by FROMCCSID and will be converted to an internal CICS code page.

  21. Containers… • EXEC CICS GET • CONTAINER (data-value) • Specifies the name (1-16 characters) of the container in which data is to be placed. Do not use names beginning with DFH, • CHANNEL (data-value) • Optional. Specifies the name of the channel that owns the container. If the channel name is not specified the current channel is used. • INTO (data-area) • Specifies the data area into which the retrieved data is to be placed. • FLENGTH (data-value) • Specifies the length of the data area to be read. • INTOCCSID (data-value) • Specifies the current Coded Character Set into which the character data is to be converted. Defaults to the CCSID of the local CICS region. • NODATA • Specifies the only the length of the data in the container is to be returned. The length returned will take into account the INTOCCSID. • SET (ptr-ref) • Specifies a data area in which the address of the retrieved data is returned

  22. Containers… • EXEC CICS MOVE • CONTAINER (data-value) • Specifies the name (1-16 characters) of the source container that is to be moved. • CHANNEL (data-value) • Optional. Specifies the name of the channel that owns the source container. If the channel name is not specified the current channel is used. • TOCHANNEL (data-value) • Specifies the name of the channel that will own the target container • AS (data-value) • Specifies the name of the target container

  23. Containers… • EXEC CICS DELETE • CONTAINER (data-value) • Specifies the name (1-16 characters) of the container that is to be deleted. • CHANNEL (data-value) • Optional. Specifies the name of the channel that owns the container. If the channel name is not specified the current channel is used.

  24. Containers… • Discovering what containers have been passed • Examples: • Output containers • Error Containers • EXEC CICS Commands • STARTBROWSE CONTAINER • CHANNEL option added • GETNEXT CONTAINER (data-area) • ENDBROWSE CONTAINER

  25. COBOL Calling Program Example IDENTIFICATION DIVISION. PROGRAM-ID. CLIENT1. WORKING-STORAGE SECTION. COPY INQINTC * copybook INQINTC * Channel name * 01 INQUIRY-CHANNEL PIC X(16) VALUE ’inqcustrec’. * Container names * 01 CUSTOMER-NO PIC X(16) VALUE ’custno’. * 01 BRANCH-NO PIC X(16) VALUE ’branchno’. * 01 CUSTOMER-RECORD PIC X(16) VALUE ’custrec’. * Define the data fields used by the program * 01 CUSTNO PIC X(8). * 01 BRANCHNO PIC X(5). * 01 CREC. * 02 CUSTNAME PIC X(80). * 02 CUSTADDR1 PIC X(80). * 02 CUSTADDR2 PIC X(80). * 02 CUSTADDR3 PIC X(80).

  26. COBOL Calling Program Example… PROCEDURE DIVISION. MAIN-PROCESSING SECTION. * ... Create CUSTNO and BRANCHNO * ... Create Channel and Container data EXEC CICS PUT CONTAINER(CUSTOMER-NO) CHANNEL(INQUIRY-CHANNEL) FROM(CUSTNO) FLENGTH(LENGTH OF CUSTNO) END-EXEC EXEC CICS PUT CONTAINER(BRANCH-NO) CHANNEL(INQUIRY-CHANNEL) FROM(BRANCHNO) FLENGTH(LENGTH OF BRANCHNO) END-EXEC EXEC CICS LINK PROGRAM(’SERVER1’) CHANNEL(INQUIRY-CHANNEL) END-EXEC EXEC CICS GET CONTAINER(CUSTOMER-RECORD) CHANNEL(INQUIRY-CHANNEL) INTO(CREC) END-EXEC * ...Process customer record EXEC CICS RETURN END-EXEC EXIT.

  27. COBOL Server Program Example IDENTIFICATION DIVISION. PROGRAM-ID. SERVER1. WORKING-STORAGE SECTION. COPY INQINTC * copybook INQINTC * Channel name * 01 INQUIRY-CHANNEL PIC X(16) VALUE ’inqcustrec’. * Container names * 01 CUSTOMER-NO PIC X(16) VALUE ’custno’. * 01 BRANCH-NO PIC X(16) VALUE ’branchno’. * 01 CUSTOMER-RECORD PIC X(16) VALUE ’custrec’. * Define the data fields used by the program * 01 CUSTNO PIC X(8). * 01 BRANCHNO PIC X(5). * 01 CREC. * 02 CUSTNAME PIC X(80). * 02 CUSTADDR1 PIC X(80). * 02 CUSTADDR2 PIC X(80). * 02 CUSTADDR3 PIC X(80).

  28. COBOL Server Program Example… PROCEDURE DIVISION. MAIN-PROCESSING SECTION. EXEC CICS GET CONTAINER(CUSTOMER-NO) INTO(CUSTNO) END-EXEC EXEC CICS GET CONTAINER(BRANCH-NO) INTO(BRANCHNO) END-EXEC ... USE CUSTNO AND BRANCHNO TO FIND CREC IN A DATABASE EXEC CICS PUT CONTAINER(CUSTOMER-RECORD) FROM(CREC) FLENGTH(LENGTH OF CREC) END-EXEC EXEC CICS RETURN END-EXEC EXIT.

  29. Java Programming • JCICS calls are provided to support Java programs • com.ibm.cics.server.Channel • com.ibm.cics.server.Container • com.ibm.cics.server.ContainerIterator

  30. Java Programming… • Creating a new channel • Create a channel using the createChannel method of the task class Task t = Task.getTask(); Channel custData = t.createChannel("Customer_Data");

  31. Java Programming… • Creating a new container • Create the container using the createContainer method of the Channel class Container custRec = custData.createContainer("Customer_Record"); • Putting data into the container • Use the Container.put() method • Data can be added as a byte array or string String custNo = "00054321"; byte[] custRecIn = custNo.getBytes(); custRec.put(custRecIn); • Or custRec.put("00054321");

  32. Java Programming… • Passing a channel to another program • Use the link() and xctl() methods of the Program class programX.link(custData); programY.xctl(custData); • Passing a channel to another task • Use the issue method of the StartRequest class StartRequest.issue(custData); • Use the setNextChannel() method of the TerminalPrincipalFacility class: terminalPF.setNextChannel(custData);

  33. Java Programming… • Receiving the current channel • Use the getCurrentChannel() method of the Task class Task t = Task.getTask(); Channel custData = t.getCurrentChannel(); Container custRec = custData.getContainer("Customer_Record"); • Getting data from a container • Use the Container.get() method to read the data in a container into a byte array: byte[] custInfo = custRec.get();

  34. Java Programming… • Browsing the current channel • Use the ContainerIterator object Task t = Task.getTask(); ContainerIterator ci = t.containerIterator(); While (ci.hasNext()) { Container custRec = ci.next(); // Process the container... }

  35. Java Programming Example import com.ibm.cics.server.*; public class Payroll { ... // create the payroll_2005 channel Task t = Task.getTask(); Channel payroll_2005 = t.createChannel("payroll-2005"); // create the employee container Container employee = payroll_2005.createContainer("employee"); // put the employee name into the container employee.put("John Doe"); // create the wage container Container wage = payroll_2005.createContainer("wage"); // put the wage into the container wage.put("2000");

  36. Java Programming Example… // Link to the PAYROLL program, passing the payroll_2005 channel Program p = new Program(); p.setName("PAYR"); p.link(payroll_2005); // Get the status container which has been returned Container status = payroll_2005.getContainer("status"); // Get the status information byte[] payrollStatus = status.get(); ... }

  37. Containers and Business Transaction Services • Containers have been used in BTS applications since CICS TS 1.3 • The container commands used in a channel context are similar to those in a BTS context • GET, PUT • MOVE, DELETE • Programs that issue container commands can be used in both a channel and BTS context • Some programming restrictions • Avoid specific reference to BTS or Channel context on commands • Cannot move containers between BTS and channels

  38. Containers and Business Transaction Services… • Channel or BTS specific options on container commands • GET command • ACQACTIVITY, ACQPROCESS, ACTIVITY and PROCESS • CHANNEL and INTOCCSID • PUT command • ACQACTIVITY, ACQPROCESS, ACTIVITY and PROCESS • CHANNEL, DATATYPE and FROMCCSID • MOVE command • FROMACTIVITY, FROMPROCESS, TOACTIVITY, TOPROCESS • CHANNEL, TOCHANNEL • DELETE command • ACQACTIVITY, ACQPROCESS, ACTIVITY and PROCESS • CHANNEL

  39. ! create the employee container on the payroll interface EXEC CICS PUT CONTAINER('employee') CHANNEL('payroll') .... ! create the wage container on the payroll interface EXEC CICS PUT CONTAINER('wage') CHANNEL('payroll') .... ! invoke the payroll service passing the payroll interface EXEC CICS LINK PROGRAM('PAYR') CHANNEL('payroll') ! examine the status returned on the payroll interface EXEC CICS GET CONTAINER('status') CHANNEL('payroll') .... DEFINE ACTIVITY('payroll') PROGRAM('payact') ! create the employee container on the payroll interface EXEC CICS PUT CONTAINER('employee') ACTIVITY('payroll') FROM('Fred Smith') ! create the wage container on the payroll interface EXEC CICS PUT CONTAINER('wage') ACTIVITY('payroll') FROM('10 pounds') ! invoke the payroll service passing the payroll interface EXEC CICS LINK ACTIVITY('payroll') ! examine the status returned on the payroll interface EXEC CICS GET CONTAINER('status') ACTIVITY('payroll') INTO(status) Simple clients use a channel to pass containers to the service BTS wrapper controls a more sophisticated application Program “PAYACT” EXEC CICS RETRIEVE EVENT(... WHEN('.... EXEC CICS LINK PROGRAM('payt') Program “PAYR” ! get the employee passed into this program EXEC CICS GET CONTAINER('employee') INTO(emp) : : ! return the status to the caller EXEC CICS PUT CONTAINER('status') FROM('OK') Container-aware programs should be insensitive to the Type of containers that are presented to them Containers and Business Transaction Services…

  40. Global User Exits • Global User Exits can create and pass channels and containers to programs they call • Changes to Global User Exits • Existence bits with channel name passed to exits • XICEREQ, XICEREQC • XPCREQ, XPCEREQC • Channel name added to the PCUE parameter list • XPCFTCH • Exits may not access contents of channels

  41. Task Related User Exits & User Replaceable Modules • Task Related User Exits can create and pass channels and containers to programs they call • User Replaceable Modules can create and pass channels and containers to programs they call • URMs may not access contents of application channels

  42. Dynamic Routing Program • Dynamic routing copybook • DYRCHANL (new field) • Name of channel associated with the request • DYRACMAA (existing field) • If the user application employs a communications area (COMMAREA), the 31-bit address of the application's COMMAREA • If the user application employs a channel and has created, within the channel, a container named DFHROUTE, the 31-bit address of the DFHROUTE container • If the user application has no COMMAREA and no DFHROUTE container, null characters • DYRLEVEL (existing field) • Level of CICS AOR required to successfully process a routed request • X’03’ – requires a CICS TS 3.1 system • DYRTYPE (existing request) • Type of request for which the routing program is invoked • 2 - Terminal related START with no data and no channel • 3 - Terminal related START with data but no channel • 4 – Program link with no channel • 6 – Non-terminal related START with no channel • 9 - Program link with a channel • A -Terminal related START with a channel • B - Non-terminal related START with a channel • DYRVER (existing field) • Version number of the dynamic routing program interface • CICS TS V3.1 number is 10

  43. Monitoring • New monitoring group DFHCHNL • PGTOTCCT • Total number of CICS requests for channel containers for the task • PGBRWCCT • Number of browse requests for channel containers for the task • PGGETCT • Number if GET CONTAINER requests for the task • PGPUTCT • Number of PUT CONTAINER requests for the task • PGMOVCT • Number of MOVE CONTAINER requests for the task • PGGETCDL • Total length, in bytes, of all the GET CONTAINER data returned • PGPUTCDL • Total length, in bytes, of all the GET CONTAINER data returned

  44. Monitoring… • Changed monitoring group DFHPROG • PCDLCSDL • Total length, in bytes, of the container data for a DPL • PCDLCRDL • Total length, in bytes, of the container data returned from a DPL • PCLNKCCT • Number of LINK requests issued with the channel option for this task • PCXCLCCT • Number of XCTL requests issued with the channel option for this task • PCDPLCCT • Total length, in bytes, of the container data passed on XCTLs • PCRTNCCT • Number of RETURN requests issued with the channel option for this task • PCRTNCDL • Total length, in bytes, of the container data RETURNed

  45. Monitoring… • Changed monitoring group DFHTASK • ICSTACCT • Number of START requests issued with the channel option • ICSTACDL • Length of the data in the containers of all the locally-executed START CHANNEL requests • ICSTRCCT • Number of interval control START CHANNEL requests to be executed on remote systems • ICSTRCDL', 4 BYTES) • Total length of the data in the containers of all the remotely executed START CHANNEL requests.

  46. Statistics • New fields in ISC/IRC system entry • Terminal sharing • Number of terminal-sharing channel requests • Number of bytes sent on terminal-sharing channel requests • Number of bytes received on terminal-sharing channel requests • Program Control • Number of program control LINK requests, with channels, for function shipping • Number of bytes sent on LINK channel requests • Number of bytes received on LINK channel requests • Interval Control • Number of interval control START requests, with channels, for function shipping • Number of bytes sent on START channel requests • Number of bytes received on START channel requests

  47. Statistics… Connection Name/Netname . . . . . : CJB2/IYK2Z1V2 Access Method/Protocol. . . . . . . . . : XM Autoinstalled Connection Create Time. . : 00:00:00.00000 Peak Contention Losers. . . . . . : 0 ATIs satisfied by Losers. . . . . : 0 Receive Session Count . . . . . . . . . : 5 Peak Contention Winners . . . . . : 0 Send Session Count. . . . . . . . . . . : 5 ATIs satisfied by Winners . . . . : 0 Current AIDs in chain . . . . . . : 0 Generic AIDs in chain . . . . . . . . . : 0 Total number of Bids sent . . . . : 0 Current Bids in progress. . . . . : 0 Peak Bids in progress . . . . . . . . . : 0 Total Allocates . . . . . . . . . : 0 Allocates per second. . . . . . . . . . : 0.00 Allocates Queued. . . . . . . . . : 0 Peak Allocates Queued . . . . . . : 0 Allocate Max Queue Time . . . . . . . . : 0 Allocates Failed - Link . . . . . : 0 Allocate Queue Limit. . . . . . . . . . : 0 Allocates Failed - Other. . . . . : 0 Allocates Rejected - Queue Limit. . . . : 0

  48. Statistics… Transaction Routing Requests Max Queue Time - Allocate Purge . . . . : 0 ____________________________ Transaction Routing - Total . . . : 0 Allocates Purged - Max Queue Time . . . : 0 Transaction Routing - Channel . : 0 Allocates Rejected - XZIQUE . . . . . . : 0 Function Shipping Requests XZIQUE - Allocate Purge . . . . . . . . : 0 __________________________ File Control. . . . . . . . . . : 0 Allocates Purged - XZIQUE . . . . . . . : 0 Interval Control - Total. . . . : 0 Interval Control - Channel. . : 0 Transient Data. . . . . . . . . : 0 Temporary Storage . . . . . . . : 0 Program Control - Total . . . . : 0 Program Control - Channel . . : 0 _______________________________________________ Total . . . . . . . . . . . . . . : 0 Bytes Sent by Transaction Routing requests . . : 0 Average Bytes Sent by Routing requests. : 0 Bytes Received by Transaction Routing requests : 0 Bytes Sent by Program Channel requests . . . . : 0 Average Bytes Sent by Channel request . : 0 Bytes Received by Program Channel requests . . : 0 Bytes Sent by Interval Channel requests. . . . : 0 Average Bytes Sent by Channel request . : 0 Bytes Received by Interval Channel requests. . : 0

  49. Program A EXEC CICS LINK PROGRAM(‘PROGRAMB’) COMMAREA(structure) Program B EXEC CICS ADDRESS COMMAREA(structure-ptr) Exploiting Channels in Application Programs • Existing application with COMMAREA • Changed application using Channels Program A EXEC CICS PUT CONTAINER(structure name) CHANNEL(channel-name) FROM(structure) EXEC CICS LINK PROGRAM(‘PROGRAMB’) CHANNEL(channel-name) EXEC CICS GET CONTAINER(structure-name) INTO(structure) Program B EXEC CICS GET CONTAINER(structure-name) INTO(structure) EXEC CICS PUT CONTAINER(structure-name) FROM(structure) EXEC CICS RETURN

  50. Transaction 1 EXEC CICS START TRANSID(‘TRN2’) FROM(structure) Transaction 2 EXEC CICS RETRIEVE INTO(structure) Exploiting Channels in Application Programs… • Existing application with START data • Changed application using Channels Transaction 1 EXEC CICS PUT CONTAINER(structure-name) CHANNEL(channel-name) FROM(structure) EXEC CICS START TRANSID(‘TRN2’) CHANNEL(channel-name) Transaction 2 EXEC CICS GET CONTAINER(structure-name) INTO(structure)

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