IBM System/360 Field Engineering Manual

CHANNEL SERVICE AIDS
INTERRUPT CONDITIONS
I. Channel Working (SIO started and now working)
II.
Exec. Inst. cc CSW Stored? Comments
SIO any CU No
No I/O opn starts
TIO any CU No
No status transfers
HIO any CU No
Irpts after halting
current operation.
TCH No Status per CC (burst}
Channel End Pending
*Channel Masked Off
*SIO any CU No
Ctlan won't start I/O
opn and will not clear
the Irpt
TIO (to unit Yes Clear Irpt store entire
pending) csw
*TIO (other CU) No Chan untouched
HIO (any CU) No
Chan stopped already
TCH No
CC says Irpt pending
*Note: Dev End can be stacked back to device level on SIO,
TIO (to other) so operation can start, CC = 0
III. Channel Clear Device End In Device
SIO (to unit 1
pending)
SIO (to other unit O
or dev)
TIO {to unit
pending}
TIO (other unit
or CU)
HIO (any CU)
TCH
Yes
(busy bit)
No
Yes
No
Yes
No
IV. Channel Clear but Irpt Pending in CU
(Dev End with other cond (unit check, etc)
SIO {unit
pending)
SIO (to other dev 1
same CU}
SIO (other CU)
TIO (Device
pending)
TIO {other dev
same CU)
TIO (other CU)
Yes
(busy bit)
Yes
No
Yes
Yes
(busy bit)
No
No I/O opn starts; Irpt
iS cleared
1/0 opn starts
Irpt cleared
All Zero status
Under these conditions
normally Device Poll Irpt
No I/O opn starts, but
clears Irpt
Status says CU busy
I/0 opn starts
Clear Irpt
Status says CU busy
V. Polling Interrupt In Channel (No lrpt Response from CPU yet)
SIO} Any of these starting cause polled in status to be stacked
TIO back into the CU. (Command Out response to the Status
mo In)
110 S/360
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IBM System/360 Specifications

General

Brand	IBM
Model	System/360
Category	Desktop
Language	English