Introduction to z/OS Basics Chapter 11: Transaction managers on z/OS © 2006 IBM Corporation
Chapter 11 Transactional Systems Chapter objectives § Be able to: § Describe the role of large systems in a typical online business. § List the attributes common to most transactional systems. § Explain the role of CICS in online transaction processing § Describe CICS programs, CICS transactions, and CICS tasks § Explain what conversational and pseudoconversational programming is § § 2 Explain CICS and Web-enabling Discuss the IMS components © 2006 IBM Corporation
Chapter 11 Transactional Systems Key terms in this chapter § BMP § BMS § conversational § CICS TS § CICS command § IRLM § multithreading § multitasking 3 § § § § task/thread region PSB IMS TM transaction unit of work two-phase commit wireless access point (WAP) © 2006 IBM Corporation
Chapter 11 Transactional Systems CSMG 4 © 2006 IBM Corporation
Chapter 11 Transactional Systems Example of online processing: a travel agency § Mainframe applications designed for: – employee and customer information – contacts with car rental companies – hotels – airline schedules § Changes must be immediately reflected to application end-users (in real time) § Contrast with batch processing 5 © 2006 IBM Corporation
Chapter 11 Transactional Systems Example of online processing (continued) 6 © 2006 IBM Corporation
Chapter 11 Transactional Systems A practical example 7 © 2006 IBM Corporation
Chapter 11 Transactional Systems Transactional systems § Requirements: ACID Ø Atomicity Ø Consistency Ø Isolation Ø Durability 8 © 2006 IBM Corporation
Chapter 11 Transactional Systems Transactional systems: terminology ØCommit and roll back ØMultitasking ØMultithreading ØThread ØReentrancy 9 © 2006 IBM Corporation
Chapter 11 Transactional Systems Online Systems and Operating Systems ØManaging and Dispatching tasks ØControlling user access ØManaging use of memory ØManaging concurrency to data ØProviding device independence 10 © 2006 IBM Corporation
Chapter 11 Transactional Systems Characteristics of a transactional systems 11 © 2006 IBM Corporation
Chapter 11 Transactional Systems Two-phase commit 12 © 2006 IBM Corporation
Chapter 11 Transactional Systems You can manage indoubt UOW 13 © 2006 IBM Corporation
Chapter 11 Transactional Systems What is CICS? § Customer Information Control System § Transactional subsystem of z/OS which: – run online applications – the same time, many users, same application(s) – manages the sharing of resources – integrity of data – prioritization of execution, with fast response. 14 © 2006 IBM Corporation
Chapter 11 Transactional Systems CICS in a z/OS system 15 © 2006 IBM Corporation
Chapter 11 Transactional Systems Languages & Platforms § - 16 Languages: COBOL OO COBOL C § Platforms: - z. Series (z/OS, OS/390, VSE) C++ - Intel servers JAVA (JCICS) - TXSeries (AIX, HP- PL/I Assembler UX, Solaris and Windows) © 2006 IBM Corporation
Chapter 11 Transactional Systems Generating a CICS Application Program Example: COBOL 1) Translated Program 2) Object Module 3) Link Edit Load Module Program Library 17 //DFHRPL DD DSN=CICSV 3. SDFHLOAD 1, DISP=SHR // DD DSN=CICSV 3. SDFHLOAD 2, DISP=SHR // DD DSN=CICSV 3. ULOADLIB, DISP=SHR © 2006 IBM Corporation
Chapter 11 Transactional Systems CICS Programming roadmap § Design application § Write & test program (includes compiling) § Define program & transaction in CICS resources § Define other resources (files, queues, etc…) in CICS resources (via RDO – CEDA) § Make resources known to CICS 18 © 2006 IBM Corporation
Chapter 11 Transactional Systems CICS in one or multiple LPARS SYS 1 LPAR A B LPAR C Other Subsyst CIC S CIC Other S CIC S Other 19 Other Subsyst FOR AOR WOR Subsyst CIC Subsyst S CIC Other S Subsyst TOR AOR Terminals Programs } one address space containing all functions Files ROR * A CICS subsystem may be composed of one or more address spaces to isolate functionality, administration and throughput. As an example: - TOR = Terminal Owning Region - AOR = Application Owning Region - FOR = File Owning Region - WOR = Web Owning Region - ROR = Routing Owning region * This is a configuration known as: Multi Region Operation ( MRO) SYS 2 TCT FCT PCT CICS Inter-System Communication (ISC) PPT CICS * CICS has strong flexibility for business configuration needs thru table definitions © 2006 IBM Corporation
Chapter 11 Transactional Systems CICS Programs, Transactions, Tasks and Tables Transaction Program Control Table (PCT) Application Program Processing Table (PPT) Files File Control Table (FCT) Terminals Terminal Control Table (TCT) PPT TCT FCT PCT **** Table Definitions are usually performed by the CICS Systems Programmer through a CICS facility called Resource Definition On-Line (RDO). It is invoke through a CICS Transaction by entering CEDA (CEDB, CEDC). 20 © 2006 IBM Corporation
Chapter 11 Transactional Systems Batch RDO 21 © 2006 IBM Corporation
Chapter 11 Transactional Systems CICS Features • Transaction Driven • Multitasking CICS • Multithreading CICS • Quasi-reentrant 22 © 2006 IBM Corporation
Chapter 11 Transactional Systems A Task executing in Multi-Tasking • Task Control • Application Program(s) • Basic Mapping Support • File Control • Program Control • Temporary Storage Control • Transient Data Control • Journal Control (logging) • Trace Control • Dump Control • Interval Control • Storage Control 23 © 2006 IBM Corporation
Chapter 11 Transactional Systems Terminal Control uses Basic Mapping Support SEND API = displaying a screen to the terminal RECEIVE API = reading data from a screen from the terminal Example: * EXEC CICS * SEND MAP (‘ORCHM 01’) During CICS program compile the API Commands are * MAPSET (‘ORCHM 01’) checked for syntax and commented out. They are then transformed into a starndard “CALL” to the * ERASE CICS Stub-routines. * END-EXEC. MOVE ‘ORCHM 01’ TO DFHEIV 1 MOVE ‘ORCHS 01’ TO DFHEIV 2 CALL ‘DFHEI 1’ USING DFHEIV 0 DFHEIV 1 DFHEIV 99. . * EXEC CICS The DFHEIVxx variables are copied in automatically * RECEIVE MAP (‘ORCHM 01’) by the CICS translator into WORKING STORAGE * MAPSET(‘ORCHM 01’) i. e. DFHEIVAR COPYBOOK * INTO (workstorage area) * END-EXEC. MOVE ‘ORCHM 01’ TO DFHEIV 1 MOVE ‘ORCHM 01’ CALL ‘DFHEI 1’ USING DFHEIV 0 DFHEIV 1 …. . 24 © 2006 IBM Corporation
Chapter 11 Transactional Systems An example of BMS map definition The MAPS are composed of three simple macros: Note: You can have several maps DFHMSD – name of mapset within a mapset definition DFHMDI – name of map identification DFHMDF – field screen definitions and location ORCHM 01 ORDER# 25 PRINT NOGEN DFHMSD TYPE=MAP, MODE=INOUT, CNRL=FREEKB, LANG=COBOL, TIOAPFX=YES DFHMDI SIZE=(24, 80) DFHMDF POS=(01, 01), LENGTH=01, ATTRB=(ASKIP, DRK, FSET), INITIAL=‘ 1’ DFHMDF POS=(01, 25), LENGTH=3, ATTRB=(ASKIP, BRT), INITIAL=‘PURCHASE ORDER - - - FILE INQUIRY’ DFHMDF POS(03, 30), LENGTH=13, ATTRB=ASKIP, INITIAL=‘ORDER NUMBER ’ DFHMDF POS=(03, 44), LENGTH=10, ATTRB=(NUM, BRT, IC) DFHMDF POS=(04, 32), LENGTH=11, ATTRB=ASKIP, INITIAL=‘DEPARTMENT’ * * * DFHMSD TYPE=FINAL x x x © 2006 IBM Corporation
Chapter 11 Transactional Systems Conversational 26 Pseudo-Conversational © 2006 IBM Corporation
Chapter 11 Transactional Systems Conversational 27 Pseudo-Conversational © 2006 IBM Corporation
Chapter 11 Transactional Systems CICS Programming commands § General format: § EXECUTE CICS (or EXEC CICS) + command § § e. g. in COBOL: EXEC CICS function option. . . END-EXEC. § CICS command example : § EXEC CICS § READ FILE(‘ACCTFIL’) RIDFLD(ACCTC) UPDATE. . . § 28 END-EXEC. © 2006 IBM Corporation
Chapter 11 Transactional Systems CICS transaction flow 29 © 2006 IBM Corporation
Chapter 11 Transactional Systems CICS transaction flow (Cont…) 30 © 2006 IBM Corporation
Chapter 11 Transactional Systems CICS transaction flow (Cont…) 31 © 2006 IBM Corporation
Chapter 11 Transactional Systems CICS services for Application Programs § Application program interface: use CICS commands § Terminal control services: use Basic Mapping Support (BMS) § File & database control services: – CICS file control (mainly VSAM) – Database control (DL/I & DB 2) § Other CICS Services: Task Control - Program Control Temporary Storage (TS) & Transient Data Control (TD) Interval Control - Storage Control - Dump & Trace Control 32 © 2006 IBM Corporation
Chapter 11 Transactional Systems Defining the screens § BMS macros: a form of assembler language § Result of an assembles : Physical Map § Physical map contains info to : – build the screen – merge variable data between program & screen – send variables back to program 33 © 2006 IBM Corporation
Chapter 11 Transactional Systems Program Control RETURN XCTL LINK LOAD RELEASE EXEC CICS LINK PROGRAM(PROGRAM-2) END_EXEC. EXEC CICS XCTL PROGRAM(PROGRAM-3) END_EXEC. 34 © 2006 IBM Corporation
Chapter 11 Transactional Systems CICS COMMUNICATION AREA (COMMAREA) This area of a program is used to pass information between other programs and transactions. • It is automatically provided to you via the Translator phase • • In COBOL it is part of the DATA DIVISION / LINKAGE SECTION It initially provides you one byte to be used as a programming SW although it can range up to 32 K bytes in size O 1 DFHCOMMAREA. 05 PROCESS-SW 88 INITIAL-ENTRY 88 VERIFICATION 05 ACCOUNT-NUMBER PIC X. VALUE ‘ 0’. VALUE ‘ 1’. PIC X(10). * * * EXEC LINK PROGRAM(ACCTPGM) COMMAREA(DFHCOMMAREA) LENGTH(11) END-EXEC. 35 © 2006 IBM Corporation
Chapter 11 Transactional Systems Example of CICS application user screen You can program PF, PA, CLEAR Keys to perform any transaction functionality i. e. EXEC CICS HANDLE AID PF 3(EXIT-PGM). . END-EXEC. 36 © 2006 IBM Corporation
Chapter 11 Transactional Systems Example of ABEND Codes 37 © 2006 IBM Corporation
Chapter 11 Transactional Systems Language Examples 38 © 2006 IBM Corporation
Chapter 11 Transactional Systems CICS JCL Startup 39 © 2006 IBM Corporation
Chapter 11 Transactional Systems Example of CICS Startup Messages on MVS Console Type Of Startup Temp Stg. Init RDO Grouplist being loaded Good Morning Msg Storage Size acquired 40 * Java Enabled Web Listener enabled © 2006 IBM Corporation
Chapter 11 Transactional Systems Example of CICS Shutdown Message from MVS Console Logs who is shutting down CICS Closing Network No Outstanding Tasks 41 © 2006 IBM Corporation
Chapter 11 Transactional Systems Example of CICS Statistics Collected 42 (DFHSTUP) © 2006 IBM Corporation
Chapter 11 Transactional Systems CICS and Web-enabling § 4 major elements of web-enabled applications: § Presentation logic § Integration logic § Business logic § Data logic 43 © 2006 IBM Corporation
Chapter 11 Transactional Systems CICS Web support 44 © 2006 IBM Corporation
Chapter 11 Transactional Systems CICS Transaction Gateway 45 © 2006 IBM Corporation
Chapter 11 Transactional Systems CICS Transaction Gateway and Web. Sphere Application Server 46 © 2006 IBM Corporation
Chapter 11 Transactional Systems CICS COMMANDS /DEMOS CEMT – Master Terminal Commands * INQUIRE (set file) * SET (disable a program) * PERFORM (Statistics) CECS – Command Syntax Check CECI – Command Initiation CEDF – EXECUTE DIAGNOSTIC FACILITY CEDA/B/C – Resource updating via RDO (See utility DFHCSDUP*) CEBR – Temporary Storage Browser CETR – Trace CSMG - Messages CSFE PRINT JCL SDSF * See next slide 47 © 2006 IBM Corporation
Chapter 11 Transactional Systems CECI 48 © 2006 IBM Corporation
Chapter 11 Transactional Systems CEDA 49 © 2006 IBM Corporation
Chapter 11 Transactional Systems CEDA EXPAND LIST(DFHLIST) 50 © 2006 IBM Corporation
Chapter 11 Transactional Systems CEDA Functions for Resource Definitions 51 © 2006 IBM Corporation
Chapter 11 Transactional Systems CEDA/CEDB/CEDC 52 Summary © 2006 IBM Corporation
Chapter 11 Transactional Systems The DFHCSDUP utility provides: 53 © 2006 IBM Corporation
Chapter 11 Transactional Systems Example of Terminal Interactions 54 © 2006 IBM Corporation
Chapter 11 Transactional Systems What is IMS? § Information Management System § 3 components: – The Transaction Manager (TM) – the Database Manager (DB) – Set of system services, providing common services to the other 2 55 © 2006 IBM Corporation
Chapter 11 Transactional Systems IMS overview 56 © 2006 IBM Corporation
Chapter 11 Transactional Systems IMS Transaction Manager messages § Four types of messages: – Transactions – To go to another logical destination – Commands for IMS – For the IMS APPC feature to process 57 © 2006 IBM Corporation
Chapter 11 Transactional Systems Summary § Interaction with the computer happens online through the help of a transaction manager. § The continued growth of the Internet has caused many corporations to consider the best ways to make their legacy systems available to users on the Internet. § CICS is a transactional processing subsystem. CICS applications are traditionally run by submitting a transaction request. § Information Management System (IMS) consists of three components: – Transaction Manager (TM) – Database Manager (DB) – A set of system services common to both TM and DB 58 © 2006 IBM Corporation
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