Is there a generation for a GDG as (-0)?

[TechBrave]

Hi,

Today, I was going through a JCL and found a GDG having its generation referred to as (-0)! This is being use as an Input to the step.
Can anybody tell me what this means? Does JCL interpret this just as a normal "current" generation of GDG?

FYI: This JCL is an Old Active JCL.

Thanks,
TB.

 

[RICHINMINN]

A GDG generation of (-0) is the same as (+0), which is the same as (0). The sign is redundant when you're dealing with a value of 0, which is neither positive nor negative. (That's just one of my pet peeves with IBM JCL.)

Rich (in Minn.)

 

[rasETL]

RICHINMINN

I wouldn't blame IBM for making +0, -0 and 0 the same,
because mathematically it is.

What I do not care for is the use of (0) in the GDG because if you need to change it to (-1) or (-2), etc., there is no simply overlay of data - you need to insert an extra character.

Because I work in an IBM/MVS environment this "having to insert an extra character" using 3270 emulator softeare and TSO is "a slight pain".

Standard Protocol where I have worked is to use (+0).

 

[stevexff]

GDGs seem like a good idea until you start working with them in complex JCL. One solution is to use a symbolic which may make it easier to change. But a number of sites I have worked at (especially if they have a scheduling package) have two jobs - one an IEFBR14 to create the +1 generation, and the second to actually run the program using -1 as input and generation 0 as output. That way you can rerun job 2 as many times as you like without having to mess around with the GDGs at all.