IBM System z Software Pricing

Monthly License Charge (MLC) Metrics

Parallel Sysplex License Charges

Parallel Sysplex License Charges (PSLC) is a monthly license charge pricing metric designed to support the high availability design of a Parallel Sysplex cluster. PSLC may be applied to many different types of mainframes including IBM System z servers, S/390 Enterprise servers, and others. A listing of PSLC-eligible servers is available on the Mainframe Exhibits section of the System z Software Contracts web site.

PSLC may be applied to a standalone mainframe environment, in this case it is sometimes referred to as PSLC/E but the per-MSU pricing is the same. However, aggregation benefits may only be applied across a fully qualified Parallel Sysplex environment. PSLC is designed to provide improved price/performance as you grow. This lower cost of incremental growth is provided via the decreasing unit cost per MSU, a key element of the PSLC price structure.

Sysplex - In a fully qualified sysplex environment, PSLC software charges are based on the total MSU value for only those machines where the products execute. This provides you the flexibility to grow your sysplex either vertically (grow an existing server) or horizontally (add a new server) and experience similar incremental software costs.

Standalone - For a standalone (uncoupled) machine, PSLC/E charges are also available. Software charges for products executing in this environment are based on the MSU capacity of the machine. In an uncoupled environment, MSU values are not aggregated with any other machines.


On 13 January 1998, IBM announced (PDF, 12KB) clarification of the Parallel Sysplex pricing terms and conditions, including detailed information on aggregation requirements.

On 13 September 1994, IBM announced (PDF, 11KB) System/390 Parallel Sysplex Software Pricing Extension (PSLC/E) for single (standalone) servers.

On 6 April 1994, IBM announced (PDF, 16KB) System/390 Parallel Sysplex Software Pricing terms and conditions for servers in a Parallel Sysplex.

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Operating Systems

IBM System z supports multiple operation systems:


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