Object access method (OAM) is an

access method An access method is a function of a mainframe operating system that enables access to data on disk, tape or other external devices. Access methods were present in several mainframe operating systems since the late 1950s, under a variety of name ...

under

z/OS z/OS is a 64-bit operating system for IBM z/Architecture mainframes, introduced by IBM in October 2000. It derives from and is the successor to OS/390, which in turn was preceded by a string of MVS versions.Starting with the earliest: * O ...

which is designed for the storage of large numbers of large files, such as images. It has a number of distinguishing features, e.g. compared to

VSAM Virtual Storage Access Method (VSAM) is an IBM DASD file storage access method, first used in the OS/VS1, OS/VS2 Release 1 (SVS) and Release 2 (MVS) operating systems, later used throughout the Multiple Virtual Storage (MVS) architecture and now i ...

: *OAM datasets do not have an internal record structure; they are accessed as binary data streams. *OAM datasets are not directly cataloged. Rather, they are stored into OAM collections, with only the OAM collection being cataloged. The reason for this is to prevent the catalog from being overloaded with large numbers of (e.g. image) files. OAM is used in conjunction with

IBM Db2 Db2 is a family of data management products, including database servers, developed by IBM. It initially supported the relational model, but was extended to support object–relational features and non-relational structures like JSON a ...

. An example use case for OAM would be storing medical images in a Db2 database running under z/OS.

History

OAM was created in the 1980s "as a prototype product for an insurance company to replace

microfiche Microforms are scaled-down reproductions of documents, typically either films or paper, made for the purposes of transmission, storage, reading, and printing. Microform images are commonly reduced to about 4% or of the original document size. F ...

." Initially OAM supported optical storage and magnetic disks. In the 1990s support for

magnetic tape Magnetic tape is a medium for magnetic storage made of a thin, magnetizable coating on a long, narrow strip of plastic film. It was developed in Germany in 1928, based on the earlier magnetic wire recording from Denmark. Devices that use magne ...

was added. In 2011 support was added for storage of objects in a z/OS unix file system—either

zFS ZFS (previously: Zettabyte File System) is a file system with volume management capabilities. It began as part of the Sun Microsystems Solaris operating system in 2001. Large parts of Solaris – including ZFS – were published under an ope ...

or NFS. In the 1990s, Object Access Method was used by the

Canadian Intellectual Property Office The Canadian Intellectual Property Office (CIPO; French: ''Office de la propriété intellectuelle du Canada, OPIC'') is responsible for the administration and processing of the greater part of intellectual property (IP) in Canada. CIPO's areas ...

to store documents related to patent processing.

References

External links

DFSMS Object Support:Data Archiving with OAM
IBM mainframe operating systems {{mainframe-compu-stub