Object access method (OAM) is an
access method
An access method is a function of a mainframe computer, 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 ...
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:
...
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:
*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. 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." 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 magnetic ...
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 manager, volume management capabilities. It began as part of the Sun Microsystems Solaris (operating system), Solaris operating system in 2001. Large parts of Solaris, includin ...
or
NFS.
In the 1990s, Object Access Method was used by the
Canadian Intellectual Property Office to store documents related to patent processing.
References
External links
DFSMS Object Support:Data Archiving with OAM
IBM mainframe operating systems
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