EASY/Exit  
 

Overview
z/OS, OS/390, and many IBM program products provide exits which give installations the ability to extend the scope and functionality of the system.

Many companies gain a strategic advantage over their competitors through the use of customised system and product exits to provide critical features and function unavailable elsewhere.

However, the use of such exits has sometimes been problematic because exits:

  • must be coded in assembler language
  • often run in an APF-authorized environment in key 0
  • sometimes required an IPL to activate or remove
  • usually require system programming specialists to develop and maintain
  • rarely have imbedded recovery and debugging facilities
  
     
  Eliminating the need for programming
EASY/Exit contains code which interfaces with each supported exit point.

This code performs the required initialisation and termination for the exit as well as establishing a recovery environment in case of errors.

Most importantly, though, the code provides access to all of the exit’s input and output parameters in the form of easy-to-use variables which can be examined, set, tested, and manipulated without the need for any programming.

The code established by EASY/Exit has everything except the logic your installation wants to implement, which you provide with a set of simple, flexible, IF-THEN-ELSE rules.		  
     
  Exits that communicate
The product provides many capabilities that are far beyond the scope of a typical exit.

Most hand-coded exits are used to make simple yes or no decisions and pass a return code to the caller. In contrast, EASY/Exit allows installations to make much more detailed and sophisticated decisions in the rules logic.

The rules can dynamically build messages and/or records, and write them:

  • to the TSO or JOB that called the exit
  • as SMF records
  • directly to specified TSO users
  • to log files allocated to the DIF started task (this can be done from environments that don’t allow I/O). The log files can be sequential or VSAM KSDS data sets.
  • to MQSeries message queues
  • to TCP/IP ports
  
     
 

Performance
Most the products written by DTS Software execute in very performance sensitive areas of the operating system.

The code used by EASY/Exit uses the same design methodologies and practices as the rest of the DTS products.

The developers are always concerned about performance, and have been very successful at creating products with very low overhead. In the usual case, the overhead of EASY/Exit processing should be so low as to be unmeasurable.
 
 

EASY/Exit uses proven technology
The developers at DTS Software have been writing highly sophisticated and functional system software products for many years.

EASY/Exit makes use of technologies written for the company’s system software products to eliminate the need for assembler-language coding and allow the use of exits in a way that is much easier to use and much more reliable.

Logic implemented through EASY/Exit can be activated or removed instantly through the product’s Dynamic Install Facility (DIF).

No IPL is ever required.
 
 
   
    IF/THEN/ELSE Language
   
   

Your installation logic is implemented with the same IF-THEN-ELSE rules language used by all DTS Software products.

EASY/Exit makes the input and output parameter information available as symbolic fields to the rules language, along with many other variables that may be useful in providing the required function.

    
       
    Example
    
   

The following rule allows additional CPU time for critical jobs running over the weekend. In this example, jobs whose names begin with the characters ’PR’ (indicating, perhaps, an important production job) are allowed up to 5 minutes of additional CPU time, in one-minute increments, if the job is executing on a Saturday or Sunday. During the week, the normal CPU time limitations apply.

    
   

DEFRULE MORETIME
   IF &ENV = JOB_CPU
      &JOBNAME = PR*
      &JOBSDAY = (SATURDAY, SUNDAY)
      &JOB_CPU_EXT LT 4
  THEN SET &ADDITIONAL_TIME = 60
            ISSUE WRITEMSG(USERMSG)

DEFMSG USERMSG
        ’CPU TIME WAS EXTENDED BY 60 SECONDS’

    
    The rules language can be changed at anytime, and updated with a simple DIF REFRESH command. The rules language has extensive debugging facilities, so you can run test jobs to watch the flow of logic through the rules.    
       
    Consolodated Rules Logic
   
    The rules used by various exits can be consolidated into a single file, or grouped into different members based on exit type. Each exit runs the rules language with environment variables (&ENV, &ENVS) set to unique values. The rules can test the environment variables, and set the other necessary variables accordingly.    
       
   

Currently, EASY/Exit supports approximately 30 exits:

z/OS Exits
DFSMShsm Exits
ABARS Exits

    
       
   

EASY/Exit Extras


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