IBM XCF
Encyclopedia
In IBM mainframe
s, a Cross-system coupling facility, or XCF, is a component of z/OS
that manages communications between applications in a sysplex. Applications may be on the same system or different systems.
Systems communicate using messages transported by one of two mechanisms:
In a parallel sysplex decisions about which of these two transport mechanisms to use for routing a specific message are made dynamically.
Within a single z/OS system messages are transported using cross-memory services, rather than being routed through either of the physical transport mechanisms.
Applications join specific groups as individual members. On joining a group a member can send or receive messages. Individual messages are assigned to specific transport classes, based on the message's size. Each transport class owns input and output buffers. Routing decisions are made at the transport class level.
IBM mainframe
IBM mainframes are large computer systems produced by IBM from 1952 to the present. During the 1960s and 1970s, the term mainframe computer was almost synonymous with IBM products due to their marketshare...
s, a Cross-system coupling facility, or XCF, is a component of z/OS
Z/OS
z/OS is a 64-bit operating system for mainframe computers, produced by IBM. It derives from and is the successor to OS/390, which in turn followed a string of MVS versions.Starting with earliest:*OS/VS2 Release 2 through Release 3.8...
that manages communications between applications in a sysplex. Applications may be on the same system or different systems.
Systems communicate using messages transported by one of two mechanisms:
- Dedicated channel-to-channel links (CTC links).
- Structures in a Coupling FacilityCoupling FacilityIn IBM mainframe computers, a Coupling Facility or CF is a piece of computer hardware which allows multiple processors to access the same data.A Parallel Sysplex relies on one or more Coupling Facilities...
, only available in Parallel SysplexIBM Parallel SysplexIn computing, a Parallel Sysplex is a cluster of IBM mainframes acting together as a single system image with z/OS. Used for disaster recovery, Parallel Sysplex combines data sharing and parallel computing to allow a cluster of up to 32 systems to share a workload for high performance and high...
, not in standard sysplex.
In a parallel sysplex decisions about which of these two transport mechanisms to use for routing a specific message are made dynamically.
Within a single z/OS system messages are transported using cross-memory services, rather than being routed through either of the physical transport mechanisms.
Applications join specific groups as individual members. On joining a group a member can send or receive messages. Individual messages are assigned to specific transport classes, based on the message's size. Each transport class owns input and output buffers. Routing decisions are made at the transport class level.