In the previous post I highlighted the most common peripherals. In this post I will describe how such a big piece of equipment is chopped up in smaller logical parts.

This post appears as part of a number of articles in the category “Don’t Be Afraid Of The Mainframe.

Logical partitions

We have seen above the mainframe machine can contain a huge amount of computing capacity. You will run all of your development, test, acceptance and production environments on this large box, so you need a way to spread all this computing capacity over these environments.  The mainframe technology provides many facilities to achieve this.

One of the main tools to setup the hardware in logical and physical parts is a tool called PR/SM (pronounced as “prism”). With this tool you can chop up the large mainframe box into smaller virtual parts called logical partitions or LPARs. These LPARs are a smaller version of the big hardware box. In an LPAR you can run your test or production system.

A common way to split the mainframe computing capacity is to distinguish separate LPARs for Development activities, for Testing activities, Acceptance activities and of course for production.

In larger computing environments, there may be separate LPARs for different types of applications, or for different business units. A bank may have separate LPARs for their wholesales business and for their retail business. Other organisations may have separate LPARs for their business analytics applications and their logistics applications.

More technical information on PR/SM can be found here

https://www.ibm.com/support/knowledgecenter/zosbasics/com.ibm.zos.zmainframe/zconc_mfhwsyspart.htm