IBM AS/400e, User Handbook Manual, Page: 529 / 834

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Operating System/400, 5769-SS1
when compared to other design models and APIs. In the typical threaded server application
design model, there is usually one thread per client connection. Each thread, especially in
applications where there is intermittent data flow being exchanged, such as an interactive
application like TELNET, spends much of its time waiting for data. This means each thread
expends CPU cycles going to sleep when no data is available or waking up when data finally
becomes available. Applications using Async IOCP designs and APIs should allow any of the
applications threads to service any client. This means fewer threads are needed per server
application, and each thread is constantly kept busy. Therefore, little or no system resource is
consumed by the server application’s threads either waiting for data, going to sleep, or
waking up.
This means that for many Internet or e-business applications designed and written to use
Async IOCP APIs, there can be a drastic and dramatic reduction in CPU utilization rates. In
general, less system CPU resource, less paging resource, less system memory, and less
system storage is needed by Async IOPCP-enabled applications.
AS/400 Logical Partitioning
Logical partitioning (LPAR) lets you run multiple independent OS/400 instances or partitions
(each with its own processors, memory, and disks) in an N-way symmetric multiprocessing
AS/400e, Model 6xx, Sxx, and 7xx. You can address multiple system requirements in a single
machine to achieve server consolidation, business unit consolidation, mixed production and
test environments, and integrated clusters.
Each partition's system values can be set independently. Partitions have different system
names and may have a different primary or secondary national language, or they may be
operated using different time zones. This flexibility is ideal for banks and other multinational
companies that want to centralize operations in a single location, yet retain the national
characteristics of each system. Logical partitioning is also ideal for companies that want to
run mixed interactive and server workloads in a single AS/400 system. Logical partitioning
allows the interactive performance of an AS/400 system to be flexibly allocated between
partitions.
All V4R4 systems have a primary partition with all resources initially allocated to it. Creating
and managing secondary partitions is performed from the primary partition. Movement of
processors, memory, and interactive performance between partitions can be achieved with
only an IPL of the affected partitions. The movement of IOP resources can be achieved
without IPL.
Logical partitions operate independently. Communication between partitions is achieved with
standard LAN/WAN facilities. OptiConnect software can be installed for high-performance
communications between partitions without the need for additional OptiConnect hardware.