Friday, September 22, 2017

Mainframe Batch Processing: What is Job Control Language (JCL)

Mainframe batch processing requires a job. Jobs are created using Job Control Language (JCL). What is in a JCL? How can you use it?

What are Generation Data Groups (GDG)

z/OS has a facility that allows you to keep versions of a file. This facility is called Generation Data Groups (GDG).

What is a Job Entry Subsystem (JES)

The Job Entry Subsystem (JES) manages jobs within an z/OS system. This article discusses the various stages in the lifecycle of a job.

Micro Focus Enterprise Analyzer

The Micro Focus Enterprise Analyzer (EA) is a tool that allows you to track your configuration items (CI’s) on the mainframe. We use it to provide an inventory of all CI’s we use so we can use the information for one of our projects.

Tuesday, December 13, 2016

Hercules/MVS Turnkey - MVS on a PC

I started my career as an operations analyst. Worked my way up to be a systems programmer for MVS. During my career as a systems programmer, I wrote several assembler programs on MVS. Those were interesting days and nights.

I was actually surprised to know that I can install MVS on my PC. The same version of MVS I supported - MVS 3.8! I know, it's not state of the art. It's just 24 bit addressing! But I think it is a good tool if one wishes to learn about operating systems in general and MVS in particular. Or if one just wants to relive old glory days in writing assembler code.

Sunday, February 15, 2015

Mainframe System Modernization: Reality Check

I just realized that the mainframe systems I support had been running for decades some even going back to the 1980’s. The interesting thing is there had been several hardware, operating system, database transaction processor and compiler upgrades, not to mention other system programs, and probably the greatest effort done on these was the Y2K conversion. Other than that, the most you probably have to do is some maintenance that takes a day to do. They all run in the production box without any tweaks to the system.

Wednesday, February 4, 2015

SYNCSORT Advanced Features

Many use SYNCSORT for sorting files. But SYNCSORT can do a lot more. It can be used to format records. Because of this feature, it can be used for other purposes. (These features are also available in DFSORT, although some features work differently in DFSORT).

Monday, October 13, 2014

z/OS File System

Every operating system has its own file system. z/OS is no exception. Windows and *NIX file systems are based on hierarchical directory structure. Basically, you have one root directory and you can create directories (sometimes called folders) or files under that root directory. Mainframe disk files are very different to this hierarchical approach.

Monday, October 6, 2014

What is an IMS Database

Information Management System (IMS) is a database and transaction management system for IBM mainframes. This article gives a basic overview of IMS Databases.

Monday, September 22, 2014

Unix System Services (USS)

Probably unknown to many in the industry, the IBM mainframe runs Unix System Services (USS) with the z/OS operating system. USS runs as a separate address space in z/OS as a started task.

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