Concepts

What's a BEE?

Core applications are usually performed through batch processing, which involves executing one or more batch jobs in a sequential flow. The Job Entry Manager (JEM) helps receive jobs, schedule them for processing, and determine how job output is processed (like IBM JES2).

Many batch jobs are run in parallel and JCL is used to control the operation of each job. Correct use of JCL parameters allows parallel, asynchronous execution of jobs that may need access the same data sets. One goal of a JEM is to process work while making the best use of system resources. To achieve this goal, resource management is needed during key phases:

• Before job processing: to reserve input and output resources for jobs.
• During job processing: to control step execution and standardize output
• After job processing: to free all resources used by the completed jobs, making the resources available to other jobs.

Have a look about how a BEE should be built.

What's a JOB?

(quoted from Batch Processing definition in Wikipedia)

Batch processing is the execution of a series of programs ("jobs") on a computer without manual intervention.

Jobs are set up so that they can be run to completion without manual intervention: all input data are preselected through scripts or command-line parameters. This is in contrast with "online" or interactive programs, which prompt the user for such input. A program takes a set of data files as input, processes the data, and produces a set of output data files. This operating environment is termed as "batch processing" because the input data are collected into batches of files and are processed in batches by the program.

What's a JCL?

(quoted from Job Control Language definition in Wikipedia)

Job Control Language (JCL) is a scripting language used to instruct the system on how to run a batch job.

In JCL the unit of work is the job. A job consists of one or several steps, each of which is a request to run one specific program. For example, before the days of relational databases, a job to produce a printed report for management might consist of the following steps:

1. a user-written program to select the appropriate records and copy them to a temporary file;
2. sort the temporary file into the required order, usually using a general-purpose utility;
3. a user-written program to present the information in a way that is easy for the end-users to read and includes other useful information such as sub-totals;
4. a user-written program to format selected pages of the end-user information for display on a monitor or terminal.

In JCL, there is a "card" to identify the job. Defines how the job as a whole is to be run, e.g. its priority relative to other jobs in the queue.

What's JEM, the BEE?

JEM, the BEE is a Java, cloud-aware application which implements a Batch Execution Environment, to help and manage the execution of jobs, described by a JCL:

1. managing different JCLs
2. providing a all necessary commands to control the job
3. providing a cross platform execution
4. providing a cross programming languages
5. providing a intelligent dispatching by affinities
6. providing a global resource system
7. providing GDG implementation
8. collecting all outputs produced by job

Have a look to additional details about JEM, the BEE!