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OPERATION AND APPLICATION
2.9.4
Taking Secondary Devices Off-line
The DISCONNECT SECONDARIES command performs the opposite function
of the CONNECT SECONDARIES command. The secondary devices listed
after the command code are logically disconnected and their addresses removed
from the secondary log. Again, the special address code FF, instructs the
UNILINK Host Adapter to attempt to disconnect all logically connected
secondaries. You must be careful when disconnecting more than one secondary
device. The command may be aborted if all secondaries are not disconnected
before the host command timeout expires and the ERROR RESPONSE will be
returned. The normal response returned will be the command code and a list of
secondaries that disconnected properly. If none of the addresses in the list were
connected, the response will be the command code and a 00 address value.
The HIU function must have permission to issue a disconnect to a secondary
before the secondary is actually taken offline. If the permission is not granted,
the secondary device will be removed from the secondary log, but will remain
online. Option–09 of the CONFIGURE NETWORK MANAGER command
defines the default for granting this permission by the background monitor. In
addition, the ALLOCATE NETWORK MANAGER BUFFERS command can
specify the permission.
2.9.5
Retrieving Adapter Statistics
The READ ADAPTER DIAGNOSTICS command, code 08, is another aid to
identifying processing problems. This command retrieves a list of counters
indicating the number of times that each Base HIU command has been
processed. This will help build a profile of which commands are processed most
often and will indicate possible bottlenecks. Like the counters for the secondary
statistics, these counters are not automatically reset when the maximum limit
of is reached.
2–29
UNILINK HOST ADAPTER
USER MANUAL
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