ACL 4/52 Software Interface Guide
Document 6211225-03
Version 3.0
2-6
Events
Events
Events are system conditions created by failures or operator actions
such as opening the door or pressing the STOP switch.
Some of these events appear as states on the control panel. For a list of
event states, see Appendix B. (The control panel does not queue these
states.)
Events are recorded in sense data. Depending on the interface, the host
can obtain the sense data either in response to a Request Sense
Command or as an Unsolicited Message.
Figure 1: Control Panel
The library does not support asynchronous event notification. This
simplifies the host/library interface and is acceptable since the events
happen infrequently and do not require an immediate host response.
The SCSI host can check for library events by issuing the Request
Sense command to the library. The event sense data is transmitted in
response to a Request Sense command. The library queues event
conditions for the library. The host can repeatedly issue the Request
Sense command to obtain each queued condition.
The most significant events are described in the sections that follow.
STOP
OPEN
CLOSE
STANDBY
FAULT
SELECT
TA00003b/15b
Control Panel
Status Display Area
(16 Characters/2 Lines)
Scrolling Buttons
(Up {
↑
}
and Down
{
↓
})