Logical partitioning (LPAR) is a technique that divides hardware resources, as opposed to virtualization
, which replicates something. Logical partitioning is only available for mainframes. With this technique, mainframes can allocate their own resources of central processing units, storage, and peripherals to each partition via special operating systems. In addition, such a system
can also include several virtual systems, each of which can run its own operating system. Logical partinioning is implemented on the hardware layer and ensures, for example in the case of memories, that each partition is assigned a specific addressing range that does not overlap with those of the other partitions. In the initial phase of logical partitioning, each partition had its own central processing unit (CPU); later, with micro-partitioning, one central processing unit managed several LPARs.As far as the fineness of partitioning is concerned, this is referred to
. Depending on the mainframe series, such systems can manage 60 or more logical partitions and patition the hardware resources. The technique of partitioning was developed by IBM in the 1990s for their mainframes and later adopted in the other mainframe series, even in those that are not designed as mainframe servers.