gtpd1m14Database Reference

Record Caching

I/O performance is greatly enhanced when cache storage can directly access DASD records in contrast to the overhead required to perform physical DASD accesses to the DASD records. TPF support for DASD record caching is available with 2 features: The 3880 Record Cache RPQ and the 3990 Record Cache RPQ.

The IBM 3880 Storage Control Record Cache RPQ is a high performance record caching storage controller specifically designed to enhance TPF DASD I/O performance. The 3880 record caching support is limited to retentive data access. TPF support for the 3880 Record Cache RPQ is referred to as record cache (RC) support.

The IBM 3990 Storage Control Record Cache RPQ is a high performance record caching storage subsystem designed to further enhance TPF DASD I/O performance. The 3990 record caching support exploits the cache fast write and DASD fast write extended functions of the 3990 hardware as well as the retentive data access function of the 3880 Record Cache support. TPF support for the 3990 Record Cache RPQ is referred to as record cache subsystem (RCS) support.

This chapter gives you an overview of the record cache features of the 3880 Record Cache (RC) and the 3990 Record Cache Subsystem (RCS) RPQ. In addition, the TPF functions that can be used in conjunction with these RPQs are described. See the following hardware publications for complete operating information: