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REXX Language
REXX: REstructured eXtended eXecutor is a structured high-level interpreted programming language developed at IBM Corporation. REXX programs tend to be shorter and easier to follow than programs written in legacy mainframe programming languages. The popularity and utilization of REXX is based upon strong parsing, high level simplicity, and interpretive support. The interpreter offers source-level interactive debugging capabilities and facilitates a streamlined development cycle. The REXX architecture works
well with the CGI: Common Gateway Architecture. RxSock provides for network communication as well as other add-ons to be used. REXX serves as a macro and scripting language with a variety of editors: Xedit, Kedit, uni-XEDIT,
ISPF Editor, and S/EDIT and software products: QMF, QMF/Calc, and SAS using SASMACRO under CMS. REXX has interfaces for graphical user interfaces and web servers which allow the development of system and user applications. Microsoft Windows and UNIX platforms support REXX. Free operating system specific downloads of REXX are available for MS Windows, Linux, UNIX, BSD, Macintosh and DOS OS. REXX also runs on operating systems
for handhold device operating systems: Windows CE, Palm OS, and Symbian/EPOC32. In spite of its wide availability, REXX primary utilization is in the IBM z/OS and z/VM mainframe environments.
REXX and IBM Corporation
In the early 1980’s with IBM mainframe computers, operating systems, and system software emerging as the foundation infrastructure for Fortune 1000 companies, government municipalities, and healthcare facilities, REXX scripts were coded for processing data and text and report generation. In the IBM mainframe environments, REXX emerged as a front end consolidator for input/output
and interactive online editing and processing of data from 3270 terminals. REXX applications were written to parse, check, and format different text and data types which were then extended with Dialog Manager. REXX was incorporated into IBM’s SAA: System Application Architecture and has continued to be included as a standard component in its operating systems. REXX has interfaces to CICS and DB2. IBM has made
versions of REXX available for Novell NetWare, Windows, Java, and Linux. REXX compilers are available for use on IBM mainframes.
REXX Utilization with DB2 and CICS Transaction Server
REXX scripts are used to manipulate DB2 UDB data and IBM’s REXX-to-DB2 interfaces provide an extended featureset. REXX scripts can issue DB2 commands through a direct interface to the DB2 CLP: command line processor. There also is a DB2 Administrative API for developing REXX scripts that manage and control
DB2 UDB for database backups and recoveries and issuing DB2 commands, and database management. The IBM REXX-to-DB2 interfaces are included with DB2 UDB for Linux, AIX, and MS Windows. IBM provides an editor for
prototyping and application coding under CICS Transaction Server. There are excellent string handling for parsing messages and building text streams. Significant advantages associated with developing REXX programs
within CICS is that the file system offers non-shared or read-only shared, unstructured data in conjunction with a hierarchical naming system without system definition.
Multiplatform and Open Source REXX
In 1996 ANSI: American National Standards Institute published the ANSI X3.274 -1996 “Information Technology - Programming Language REXX”. In 2004, IBM released the source code for Object REXX under the Common
Public License. Object REXX is a superset of the REXX language and supports object-oriented programming: messaging, classes, objects, single and multiple inheritance, data hiding and encapsulation,
polymorphism and operator overloading and a large class library. REXX programs can run under Object REXX without alteration. Object REXX contains a WSH scripting engine for developing REXX application with the
MS Windows operating system. The installation of a command-line REXX interpreter provides the capability to run ooRexxScript programs from the command line with the CScript command by invoking the Windows
Scripting Host.
NetRexx is a Java-compatible REXX-like language which coexists interchangeably with Java code and runs under the JVM: Java Virtual Machine. NetRexx is used to develop classes for use by Java
programs. Applications, applets, servlets, and beans can be developed with NexRexx and then used with Java components. A benefit associated with NetRexx is the generation of fully commented Java code. NetRexx
compiles to Java byte-code using Java source code; there are no reserved keywords and it uses the Java object model. It is not upwards-compatible with standard REXX.
Microsoft Resource Development Kits provided a REXX interpreter for the Windows command line. Portable REXX by Kilowatt and Personal REXX by Quercus are MS-DOS REXX interpreters designed for MS-DOS which also can
be run under using a command prompt on MS Windows.
REXX scripts and macros can be developed using an open source, database-independent interface; this promotes script portability. The REXX/SQL product provides database independence for
issuing DML, DCL, and DDL SQL statements from within REXX scripts. REXX/SQL scripts can be redirected from one database target to another such as converting from Oracle to DB2 UDB. This will be useful for organization’s that support more than one database product and there is a requirement for consistent access to data. REXX/SQL supports the major databases and runs under the major operating systems: Linux, UNIX,
and MS Windows. REXX/SQL product supports the standard database featureset: 1- Issuing DML, DCL, and DDL statements, transaction control with COMMITs and ROLLBACKs 2- Concurrent database connections, cursors,
and auto-commit 3- Dynamic statement preparation and bind variables 4- SQL control structures 5- Retrieval and setting of database interface behaviors.
REXX Training by SYS-ED
SYS-ED staff and CETi Technology Partners coded first generation REXX, Clist, and Dialog Manager programs. Our REXX training service draws upon this skillset and multidisciplinary experience
in IBM mainframe system software to train information technology personnel to develop and repurpose REXX programs, and scripts in the following industries: 1- Banking and finance 2- Energy and exploration companies 3- Federal government 4- Telecommunications companies 5- Software companies.
Over the past quarter century, we have provided industry standard REXX training and tailored courses in order to provide data and information technology personnel with the knowledge and
foundation skills to:
IBM's information agenda is built on its proprietary operating systems and system software. Its foundation is to simplify, collaborate, reuse, and
standardize. SYS-ED's REXX and mainframe course offerings, training programs, and software specific websites have been designed to add value-added service
to this strategy and IBM's cloud computing initiatives.
1- Delivery of content through multiple delivery medium as part of a collaborative environment for integrating data at a business level.
2- Student hand-outs, reference guides, and validation assessment for training human resources that leverage existing investments in software infrastructure.
3- Application development accelerators in the form of industry and client-specific training aids, examples, templates, and data modeling.
4- Support services in the form of technology updates, knowledge base, answers to questions, and tailored documentation in hybrid and interrelated information technology.
Few consulting or training companies have the experience and library of REXX
stepwise teaching examples and sample programs that we do. And truth be told when it comes to addressing challenging consultancy level REXX
training assignments, IBM itself will call upon SYS-ED systems consultants for our specialized expertise and presentation skills.
Performance Objectives
SYS-ED REXX courses teach:
- The new facilities for hybrid operating environments with different API’s and user interfaces.
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- OOP syntax and statements.
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- How to create REXX execs which can execute on any platform or REXX implementation.
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- How DB2 can be accessed from REXX to run queries and update tables.
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- How to capture system information, store the information and create a database of system data which can then be manipulated and managed.
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- How to access services on the system in order to code full screen data entry screens; historically this has been done with Dialog Manager.
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- How to use REXX for creating CGI programs that access z/OS based resources for web browser based users.
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Courseware Superior by Design
SYS-ED's REXX courseware incorporates industry standard content and consultancy derived techniques for designing, coding, and debugging REXX code, inclusive of performance optimization. The classic principles of adult learning are applied to the content, interpreting and translating subject matter into
performance objectives, narrative descriptions, and diagrams which explain the design, program logic and underlying architecture. The collective efforts of our
subject matter experts are
managed by editors, who have multidisciplinary expertise in information technology, text book authoring, and degrees in management and business administration. Our courseware library has been incrementally
augmented, revised, and maintained. It is highly valued, especially with the REXX programming language, where there is a scarcity of up to date text books.
Upon completion of a instructor-led course at the client location, it is standard policy to organize subject matter for future utilization in a web-based training
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