Extended Adaptive Cache - IBM AS/400e User Handbook Manual

AS/400e Advanced Technology
AS/400 Integration with Windows NT Server
AS/400 Integration with Windows NT Server is a nonchargeable feature of OS/400. This
feature provides the device drivers to enable Windows NT Server to run on the AS/400
Integrated Netfinity Server and to share AS/400e disk, tape, and CD-ROM drives. It also
provides a variety of utilities, including integrated user administration.
Windows NT Server Requirements
The AS/400 Integrated Netfinity Server is certified to run Microsoft Windows NT Server 4.0. A
standard CD-ROM licensed copy should be purchased separately (with the required client
licenses) from any Microsoft reseller.
AS/400 Integrated Netfinity Server
The AS/400 Integrated Netfinity Server combines the power of an Intel Pentium II processor
with the high reliability and availability of AS/400e servers.
The AS/400 Integrated Netfinity Server is available on all AS/400e 64-bit RISC models in
either PCI bus or SPD bus versions. Integrated Netfinity Servers are considered features of
the AS/400e system and are covered by the AS/400e system warranty and maintenance
contract. A standard PC display, keyboard, and mouse must be attached to the AS/400
Integrated Netfinity Server.

Extended Adaptive Cache

Extended Adaptive Cache is an advanced read cache technology that improves both the I/O
subsystem and system response times by reducing the number of physical I/O requests that
are read from disk. Extended Adaptive Cache operates at the disk subsystem controller level
and does not affect the AS/400e system processor. Management of the cache is performed
automatically within the I/O adapter and is designed to cache data by using a predictive
algorithm. The algorithm considers how recently and how frequently the host has accessed a
predetermined range of data.
The design of Extended Adaptive Cache is based on specific data management strategies of
the AS/400e system. Whether the disks are device parity protected, mirrored, or unprotected,
the data stored on the disks has a tendency to occur in bands. This means that there are
physically contiguous areas of disk storage that fall under one of the following categories:
• Areas where the data is actively read
• Areas of data that are both actively read from and written to
• Areas that are frequently written to
• Areas of storage that are not frequently accessed
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AS/400e System Handbook