8.78 IODELAY (Display or set I/O delay value)
8.78.1 Function
The IODELAY command displays the current setting or sets the amount of time in microseconds to wait
after an I/O interrupt is ready to be set pending. The purpose of this parameter is to bypass a bug in the
Linux/390 and z/Linux ‘dasd.c’ device driver. The problem is more apt to happen under Hercules than on
a real machine, as Hercules may present an I/O interrupt sooner than a real machine.
NOTE: OSTAILOR L
INUX no longer sets IODELAY to 800 since the problem described above is no
longer present in recent versions of the Linux kernel.
8.78.2 Syntax
Descriptive
usecs
Diagram
¬¬¬¬ ¬¬¬¬¬¬¬¬¬¬ÊÍ
usecs ¬¬¬§¬¬¬¬¬¬¬¬¬¬¬¬¬¬«
8.78.3 Parameter
usecs
Amount of time in microseconds to wait after an I/O interrupt is ready to be set pen-
ding.
NOWARN
If the IODELAY value is non-zero a warning message will be issued unless NOWARN
is specified.
8.78.4 Examples
Example 1:
Display the current IODELAY value.
HHC00013I Herc command: 'iodelay'
HHC02203I iodelay : 0
Figure 160: IODELAY command (display value)
