VPARS (Virtual PARS)
VPARS is a software enhancement to z/VM that allows multiple virtual machines to transparently share a TPF (Transaction Processing facilty) database. Although the TPF records that are modified are maintained on a VPARS database, it appears to each TPF system that it is actually writing to the TPF base. This provides record isolation between virtual machines that are sharing a TPF system. All levels of TPF are supported by VPARS.
Multi-level (or “concatenated”) VPARS databases allow several VPARS databases to be searched for TPF input records. The primary VPARS database is normally a read-write database. The rest are always read-only. Several users can share a read-only VPARS database. This may reduce the number of records required on each user’s read/write VPARS database, since a shortload or longload (or any other data) can be written to a database which is then shared read-only among several VPARS users. The primary database can also be a read-only database.