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CSKL - C ICS S erves, K nowing L egacy ( is still making most profit for the organization ).
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CSKL - CICS Serves, Knowing Legacy (is still making most profit for the organization). How Nat System switched from APPC over SNA to sockets over TCP/IP for the communication between client (Windows application) and server (CICS on z/OS), using the IBM-provided CSKL listener transaction by implementing a "child server" process, thereby leveraging its original three-tiered separation-of-concern approach. Advantages and drawbacks of short-living TCP connections used in this approach. Set-up and configuration of the CSKL.
Agenda • Who am I and where do I come from? • NatStar is just as dead as the mainframe ;-) • CICS and TCP/IP • What did we use it for and how?
[ THEe- PROCESSCOMPANY ] GFI-Adelior WELKOM - BIENVENUE - WELCOME
Aquisition NAT Systems Withdraw from Europe 2006 COGNICASE (CAN) 1998 1999 2000 2001 2002 2006 NAT SYSTEMS (FR) EMD 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 Integration into Application Engineering Project Development Adelior Java / J2EE adelior benelux GFI 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 1993 ADELIOR (FR) 2002 History
What we do • Information systems: designing and building, integration and implementation - the whole system life cycle • Manage large and complex projects • BPM • Technologies: Java, web services, web semantics, Client/Server... • Infrastructure services: Linux, Microsoft • Business intelligence: BO, Cognos… • Application software solutions: accounting, time management...
NCL Information Modelling Process Modelling GUIBuilder Repository API NatStar Development Environment
Separation of concern Application uses Operating System Services Presentation Services Application Services Data Services DBMS Services GUI Services Communication Services
Generation • NCL for all Application Objects • Generation of ANSI C code • Specific to target platform • Compilation on required targets Code Desktop to Mainframe
CICS TCP/IP • Different flavours nowadays • We use “TCP/IP Socket Interface for CICS” • “Vanilla” TCP socket programming
Listener • CSKL - The Concurrent Server • Child Servers • Take Socket
EBCDIC • Extended Binary-Coded-Digit Interchange Code • Code Pages • Little/Big Endian • Data Conversion is an issue
Short-living TCP connections • Perfect match for short-living transactions • Eliminates effect of user “think-time” • Great for automatic fail-over • Server is stateless • Server is stateless • Overhead of connection set-up • “TIME_WAIT”
Set-up & Configuration • EZAC • Define resources (mainly the listener) • Tuning (RTFM!) • Default values are not too bad
Some resources • The listener • CSKL Transaction • EZACIC02 Program • Configuration • EZAC Transaction • Operation • EZAO Transaction • netstat
Hints & Tips • Design is ever so important • Know what to expect both ways • RTFM!
The F...ine Manual • That’s in the Communications Server Bookshelf z/OS Communications Server IP CICS Sockets Guide Version 1 Release 5 Document Number SC31-8807-02 Program Number5694-A01 and 5655-G52
Questions • Questions? • Comments? • Remarks? • Thoughts? • Considerations? • Issues? • Anxieties?