gtpm6m0g | Main Supervisor Reference |
Common I/O (CIO) supports System/370 XA I/O architecture for processors executing in ESA (ESA/370 and ESA/390) mode. This support includes:
In ESA mode, all I/O operations are directed to subchannel numbers. The subchannel numbers are generated in ascending order, starting with 0. A symbolic device address (SDA) is the user's designation for the subchannel associated with a particular device.
CIO code, included as part of IPLB, allocates and initializes the following control blocks as part of system initialization:
These functions include processing the system macros that request I/O services, initiating I/O operations, and intercepting the I/O interrupts and delivering them to the TPF device interrupt handlers.
The system macros used to request I/O services include the following:
A system macro, CIOSC, allows real-time (E-type) programs to mount, dismount or request status for an SDA.
This mode provides similar functions to the normal CIO activity. I/O operations are initiated, interrupts are intercepted, and an interface to PIO device interrupt handlers is supported.
The following PIO macros are supported:
Additional information regarding the macros can be found in TPF System Macros and TPF General Macros.