IBM ESA/390

System/390 ( S/390 also ) is the name given to one by IBM ESA/390 ( Enterprise Systems Architecture/390 ) built by IBM mainframe family. It was introduced in 1990.

It is the successor to the System/370 series. She is known in its current 64- bit variant as a system for

IBM made ​​in the course of the 1990s Server in six generations (G1 to G6 ) of the S/390 architecture available. The first generation even bipolar transistors used in the CPU, while the CPUs of the later generations based on CMOS technology. The range of functions ( instruction set ) of the CPU has been extended in the course of these generations, such as an IEEE -compatible floating point unit was only introduced with the G5 CPUs.

CMOS-based CPUs in the servers were manufactured by IBM in so-called multi-chip modules ( MCM) on a ceramic plate with cache memory and I / O interfaces connected to a processor module. The smallest of these MCMs are located in the Multiprise -3000 models (G5 ) with three CPUs, while the MCMs of the great models accommodate 14 CPUs.

S/390-CPUs be divided into various groups:

  • PU ( Physical Unit ): a physically existing CPU, PUs are assigned to different purposes dedicated: CP ( Central Processor ) for the execution of client programs available PU. If the machine at POR ( Power On Reset ) was launched in LPAR mode, two types can be used by CPs in the configuration of logical partitions of the Machine: Dedicated: Dedicated CP - is 100% just this logical partition available
  • Shared: Shared CP - can be shared with other logical partitions

S/390-basierte or S/390-kompatible systems were also prepared by the IBM competitors Hitachi and Siemens, which distinguish these machines even in hardware details that affect device drivers from the IBM-S/390-Servern.

Emulators

  • FLEX -ES, very efficient, i386 - specific, commercial product
  • Hercules, platform-neutral, open source, emulating the z / Architecture ( esame ), which S/390 compatible 64 -bit successor architecture for S/390, the computer architecture of the IBM System z server.
Floating-point unit Logical partition (virtual computing platform) Hercules (Emulator)
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