IOSB heading information

Common name: IOS (I/O Supervisor) Block
Macro ID: IECDIOSB
DSECT name: IOSB
Owning component: I/O Supervisor (SC1C3)
Eye-catcher ID: IOSB, if IOSB extension exists
Offset:  06C
Length:  4 Bytes
Storage attributes: Subpool:   Any subpool that satisfies fixed
global storage attributes. Subpool
245 or 226 when obtained from the
IOS storage manager.
Key:       0
Residency: Below the 16M line when obtained .
from the IOS storage manager.
Other IOS drivers could obtain
the IOSB from either below
or above the 16M line.
Size: 108 bytes for basic IOSB.
44 bytes for an in-line extension (optional).
Created by: User of the STARTIO service
Pointed to by: IOQIOSB of IECDIOQ
SRBPARM of IHASRB
RQESRB field of the RQE data area
Serialization: None
Function: The IOSB contains all the information needed
to process an I/O request through the I/O initiation and
completion. It is used to communicate between the I/O
supervisor and the requestor of an I/O service, between
the I/O supervisor and and error-recovery procedure,
between an ERP and write-to- operator and
statistics-update modules, and among the components of
the I/O supervisor. It is also used to control successive
entries from the I/O supervisor to an ERP.