You can use Extended Adaptive Cache to improve system performance by collecting disk usage data, and then using those statistics to create a cache, effectively reducing the physical I/O requests for the disk.
Improve your system performance with Extended Adaptive Cache. Extended Adaptive Cache 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 generates statistical information for the data and then uses a mix of management strategies to determine which data to cache.
In V5R4, Extended Adaptive Cache is supported on older systems. Extended Adaptive Cache uses the feature code, #4331 1.6 GB Read Cache.