ppt tp01 cics 01
TRANSCRIPT
CICS – Mainframe (LC)
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Course Schedule
• Day1 - Introduction to CICS
• Day2 - Basic Mapping Support
• Day3 - Application Programming
• Day4 – File handling and Temporary Storage
• Day5 - Control Operations
• Day6 – Project
• Day7 - Project
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Pre-requisites
MVS and TSO/ISPF subsystem
VSAM concepts
OLTP concepts
Programming in COBOL
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Evaluation Mechanism
Component Marks Schedule
Project 50 Day 6 & Day 7
Module Test 50 Day 8
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ReferencesTITLE AUTHOR PUBLISHER
CICS for COBOL programmer
Doug Lowe Mike Murach & Associates
CICS Handbook Kageyama Tata McGraw Hill
CICS command level Programming
Alida M Jatich John Wiley and Sons Inc.,
CICS using COBOL Andrew M. Suhy Galgotia
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References• CICS Programming Using Cobol -
http://kshop.ad.infosys.com/asp/Search/DispDoc.asp?DocNo=62157&KCURating=5.4&ContentType=BOK
• Pseudo Conversational programming in CICS -•
http://kshop.ad.infosys.com/asp/Search/DispDoc.asp?DocNo=58693&KCURating=5.4&ContentType=InternalTutorial
• CICS Overview and useful - http://kshop.ad.infosys.com/asp/Search/DispDoc.asp?DocNo=11074&KCURating=8.27&ContentType=BOK
• CICS - A Beginners guide - http://kshop.ad.infosys.com/asp/Search/DispDoc.asp?DocNo=7745&KCURating=7.78&ContentType=ExternalTutorial
Introduction to CICSDay 1
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Objectives
• What is CICS?– Brief History of CICS
– Batch and Online Systems
– CICS system components
• Basic concepts of CICS– Concept of a transaction
– CICS Control Tables
– Concept of Multitasking, Multithreading and Quasi-reentrancy
– Command level and Macro level programming
– Conversational Vs Pseudo-conversational programming
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What is CICS? (Customer Information Control System)
CICS
VTAM
BTAM
TCAM
ApplicationPrograms
VSAM
DB2DASD
TERMINAL
IBM definition: “CICS is a DB/DC control system”.
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Brief History of CICS• Introduced by IBM in 1968 – ran only on IBM
mainframes
• CICS on many platforms
• Introduction of Transaction Server
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Batch On-line• Jobs are submitted for
execution by the processor at later time
• Absence of any interaction from user
• Program starts, processes
all records and ends• Performance measure is
throughput• When program ABENDS
it just ends the program
• Jobs submitted are executed immediately
• User interaction is an usual thing
• Program starts, process a record and ends
• Performance measure is response time
• When CICS program ABENDS it may bring down the entire system
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Features of CICS• A Data Base/Data Communication (DB/DC)
control system
• Is a generalized transaction processing interface
• Provides on-line environment in batch OS
• Is an operating system in itself
• Runs as a batch job within the OS/390 OS
• Many languages can be used for developing CICS programs – COBOL being the most common
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CICS Environment
Batch Job2Batch Job2
Batch Job3Batch Job3
OPERATING SYSTEMOPERATING SYSTEM
Batch Job1Batch Job1
CICS REGIONCICS REGION
PGM1PGM1 PGM2PGM2 PGM3PGM3
TerminalsTerminalsFile SystemFile System
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CICS Environment
DatabaseAccess method
DL/1, DB2
TelecommunicationAccess Method
VTAM, TCAM, BTAM
DataAccess method
VSAM,BDAM
MVS OS
Data handlingServices
DataCommunication
Services
Monitoring Services
System Services
Application ProgramServices
CICS
CICS Application Programs (COBOL, PL/1, Assembly)
TerminalsDASD
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What does CICS do?
• Telecommunication
• Multitasking
• Data access and transaction control
• Inter System communication
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IBM 3270 Terminals • Mainly consists of
1. A CRT Monitor and
2. A Keyboard.
• Examples:
1. 3278 (Monochrome, usually Green, White or Amber)
2. 3279 (7 different colours)
• Has better Keyboard Layout• Keyboard could be configured for foreign languages
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IBM 3270 Terminals CRT Monitor
Capable of displaying up to 1920 characters
along 24 rows and 80 columns.
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IBM 3270 Terminals Key board
Aid KeysPF keys
PF1 to PF24&
ENTER
PA keys
PA1 to PA4&
CLEAR
Non-Aid Keys
Alphabets, numberspunctuation and
special characters.
Allows transfer of data.
Doesn’t allow transfer of data.
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Some Basic Terminologies
• Task: Task is a unit of work specific to a user
• Transaction: A CICS program cannot be directly invoked and is done through a transaction
• Difference between transaction and task is, although several users can invoke a transaction, each user initiates his own task
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Some Basic TerminologiesLogical Unit of Work:
A piece of work, that should be done completely or not done at all.
Application: Is a collection of programs that accomplish some specific task for the end user
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CICS Nucleus – Control Programs
1. TCP (Terminal Control Program)
2. KCP (Task Control Program)
3. PCP (Program Control Program)
4. FCP (File Control Program)
5. SCP (Storage Control Program)
and many more like TSP (Temporary Storage Program) and SIP (System Initialization Program)
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CICS Nucleus – Control Tables
1. TCT (Terminal Control Table)
2. PCT (Program Control Table)
3. PPT (Processing Program Table)
4. FCT (File Control Table)5. RCT(Resource Control Table)6. And many more…
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Inside CICS• Starting a transaction
• Flow of control during a transaction
list screenFile
Control
Program
Library
Employee
File
Operating System
Terminal
BMS
Program
EMPLIST
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TransactionB021
Transaction Programs
B011 PB011B021 PB021B031 PB013
PCT
Program Location
PB011 In StoragePB021 On DiskPB031 In Storage
PPT
Library Load Module
PB011 PB011 PB031 PB031 PB021 PB021
PB011
PB021
CICS Address space
Infosys Technologies Limited
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CICS Concepts• Macro level
• Command level
• Multitasking
• Multithreading
• Quasi reentrancy
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More CICS Concepts• Conversational programming • Pseudo-conversational
programmingOperations
1.Display list screen.
2.Wait for user input.
3.Receive list screen.
4.Read employee records from the employee file.
5.Display records in formatted form.
6.Wait for the user input.
7.Receive the screen.
8.Depending on the function key populate new list.
9.Redisplay the list.
Tasks Operations
First 1. Display list screen.
Second 3. Receive list screen.
4. Read employee records from the employee file.
5. Display the records in formatted form.
Third 7. Receive the screen.
8. Depending on the function key populate new list.
9. Redisplay the list.
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Pseudo Conversation• Conversation
– Sending a message to the terminal and receiving a response from the user is called as one conversation.
• Ex.: Display a menu on the screen and receive an option from the user.
• Modes of Conversation– Conversational Mode
– Pseudo-Conversational Mode
– Non-Conversational Mode
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Advantages of Pseudo -Conversation • Resources are best utilized (The Resources are
released as soon as the program is suspended temporarily)
• Looks as if it is in conversational mode
• Better response time
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Native CICS Commands
CESN: CICS Execute Sign ON
CEDA: CICS Execute Definition and Administration
CEMT: CICS Execute Master Terminal
CECI: CICS Execute Command Interpreter
CEDF: CICS Execute Debug Facility
CMAC: CICS Messages for Abend Codes
CESF: CICS Execute Sign OfF
CEBR – CICS Execute temporary storage BRowse
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Summary• What is CICS?• Why CICS in MVS?• How is CICS similar to OS?• What are AID, PF, PA keys?• What are transactions and tasks?• What is Multitasking, Multithreading, Quasi-reentrancy?• What are the ways of starting a transaction?• What are the CICS tables?• What is conversational and pseudo-conversational
programming?• What are the native CICS Commands
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Thank You!