iSeries Architecture: Fundamental Strength of the iSeries14 iSeries HandbookHierarchy of MicroprocessorsThe iSeries servers are designed for business computing. One of the fundamentalcharacteristics of that environment is that it is I/O-intensive, rather than compute-intensive. Inaddition to outstanding performance in the business environment, the microprocessorhierarchy design gives the iSeries server an elegant method of integrating diverseenvironments into a single, harmonious customer solution.The microprocessors that look after a particular I/O device are accommodated on I/O cardsthat fit into slots on the system buses. One of these cards may be the Integrated xSeriesServer. This is a PC on a card, which enables the iSeries to run a Windows NT server, forexample.The following figure shows a range of iSeries processors dedicated to a particularinput/output (I/O) device type.A single large iSeries configuration can have well over 200 processors. The main systemprocessor complex (can be comprised of 24 separate processors) can encounter a requestfor data to be read from or written to any I/O device. That request for data is delegated to theparticular microprocessor dedicated to that I/O device. Meanwhile, the main system1.0 GB/s1.0 GB/sM emory M emoryM emoryM emoryHigh SpeedInterconnect SwitchI/O Hub M emoryControl4.8 GB/s 4.8 GB/s4.8 GB/s4.8 GB/s2.4 GB/s 2.4 GB/s2.4 GB/s 2.4 GB/s2.4 GB/s 2.4 GB/s2.4 GB/s 2.4 GB/s2.0GB/s1.0 GB/s1.0 GB/sI O P I O PI O P I O PI O P I O P I O PP C I B U SP C I B U SP C I B U SP C I B U SHSLAdapter2.0GB/s
