What Jol Does (in plain English)

Jol is a universal command language designed to replace or massively simplify IBM mainframe JCL. Think of it as a high‑level, English‑like scripting language that controls jobs, data sets, programs, scheduling, and networking on MVS/TSO systems.

It sits above the operating system and gives you a cleaner, more powerful way to run and manage batch workloads.

Here’s what that means in practice.

1. Jol replaces JCL with a simpler, English‑like language

JCL is notoriously rigid and error‑prone. Jol removes most of that pain:

• Free‑form syntax

• English‑like commands

• No positional parameters

• Minimal keywords

• Far fewer coding rules

Example from the manual:

Code: 5 TRKS

instead of: SPACE=(TRK,(5))

Or Code: IF A=10 | B=2

instead of: COND=((10,NE,A),(2,NE,B))

It’s basically JCL without the suffering.

2. Jol defines programs, datasets, and jobs in a structured, readable way

You can declare:

• Programs

• Data sets (old, new, temporary)

• Printers

• Card images

• Symbolic variables

And then run them with simple commands like:

Code

RUN UPDATE;

PRINT OUTPUT;

CATLG OUTPUT;

3. Jol automates scheduling and job networking

This is one of its biggest strengths.

Jol can:

• Run jobs on specific days (MON, TUE, HOLIDAY, JUL12, etc.)

• Run jobs only on workdays or weekends

• Trigger jobs based on dates, conditions, or symbolic variables

• Build job networks (dependencies)

Example:

Code

NETWORK ONE;

SUBMIT JOB1;

SUBMIT JOB2;

SUBMIT JOB3 AFTER JOB1 & JOB2 ENDED;

ENDNET;

This is basically a built‑in job scheduler and dependency engine — written entirely in Jol itself.

4. Jol can dynamically generate JCL or bypass JCL entirely

You can choose:

Dynamic Allocation Mode  

• Jol runs jobs directly under TSO or batch without generating JCL.

JCL Generate Mode  

• Jol produces optimized JCL for the OS to run.

This makes it compatible with legacy environments while still modernizing workflows.

5. Jol includes a data‑set attribute database

This is surprisingly modern for 1999.

Instead of coding DSNs, RECFM, LRECL, SPACE, UNIT, etc., you can store all attributes in a central database.

Then Jol automatically merges them when needed.

Example:

Code

SORT CARDS TO SORTED.CARDS;

No attributes needed — Jol looks them up.

This also gives it UNIX‑like portability.

6. Jol can read, write, allocate, and manipulate datasets directly

It has built‑in commands for:

• ALLOCATE

• OPEN

• READ

• WRITE

• COPY

• DELETE

• CATALOG

• LISTCAT

• RENAME

• COMPRESS

• MERGE

• SORT

It’s basically a scripting language with full dataset I/O.

7. Jol supports symbolic variables and logic

It has real programming constructs:

• IF / THEN / ELSE

• DO / END

• AND / OR

• Arithmetic

• String manipulation

• Date/time access

• Error handling

Example:

Code

IF %DAY='THURSDAY'

THEN SUBMIT PAYROLL;

Or:

Code

IF UPDATE=0 THEN CATLG OUTPUT;

This makes it far more expressive than JCL.

8. Jol supports restarts and generation data groups intelligently

It can:

• Reset relative generation numbers automatically

• Skip to specific steps with STARTAT

• Handle reruns without recoding

• Manage GDGs more safely than JCL

Example:

Code

STARTAT PRINT;

Jol recalculates generation numbers so the job still works.

9. Jol allows user exits for enforcing standards and security

You can write exits to:

• Validate job cards

• Enforce naming conventions

• Restrict dataset access

• Block dangerous operations

• Insert setup cards

This gives installations strong governance.

10. Jol includes a macro system to create new commands

You can extend the language itself.

Macros let you define new Jol instructions that behave like built‑ins. This is how many of Jol’s own commands are implemented.

11. Jol includes a CAI (Computer Aided Instruction) training system

It has an interactive “Teach Yourself Jol” course with menus, tests, and panels.

In short: What Jol is

Jol is:

A high‑level, English‑like command language that replaces JCL, automates scheduling, manages datasets, networks jobs, and provides a powerful scripting environment for IBM mainframes.

It’s basically:

JCL + CLIST + REXX + Scheduler + Job Network Engine + Dataset Manager + Macro Language  

all rolled into one unified system.

If you want, I can also:

• Summarize Jol in one paragraph

• Compare Jol to JCL, REXX, or modern tools

• Extract all commands and describe them

• Explain how Jol would map to a modern Kubernetes or cloud workflow (this could be fun given your ARM cluster project)

Just tell me what direction you want to go.