Hi can any one Explain what is OSAM file. Im just want to know about it out of my curiosity i have came across this, but it not a part of any of my requirements.
OSAM stands for Overflow Sequential Access Method.
Converting VSAM databases to OSAM increases the addressing capability twice that of VSAM and requires no change in current application program and PSB with minor change in DBD.
It can support addressing or indexing capacity up tp 8 GB per partition where as VSAM is limited to 4GB.
So, OSAM is one of the large datebase alternatives.
At right now I am working on this for IMS databases.
With the release of DFSMS/MVS 1.3, if VSAM data set is SMS-managed and defined as extended format(to use EA), the new size limit for an EA data set is determined by either
1. multiplying the CI size by 4 GB
2. multiplying the volume size by 59
The original limit was based on a 4-byte Relative Byte Address (RBA), but the new system uses an 8-byte RBA that creates a new limit of 128TB.
